516 posts · 447,425 views

I am a physician interested in clinical neuroscience research. I will use this blog to post more detailed analysis of recent studies in addition to my @WRY999 Twitter scientific reading log. I will also post some of my wildlife/sports photography. Aim to educate and amuse. Not selling anything.

William Yates, M.D.
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March 19, 2014
12:01 PM
491 views

Naptime Stories Boost Word Learning in Children

by William Yates, M.D. in Brain Posts

Sleep is known to have a beneficial effect on the consolidation of memory.There have been few studies to demonstrate how this effect my be utilized.Williams and Horst recently tested the effect of storybook reading, sleep and word learning in group of 3 year old children.Their study recently published in the journal Frontiers in Psychology randomized 48 three year old children into four groups:Group one: children were read the same story before a napsGroup two: children were read different stories before napsGroup three: children were read the same story without a following napGroup four: children were read different stories without a following napAll children were tested on a immediate word memory task, followed by subsequent testing at 2.5 hours, 24 hours and 7 days.The key results of the study included:Word learning was highest in the children read the same stories before a napNapping improved word learning in children read different stories compared to the non-nap groupChildren read different stories without naps never caught up to other groups word learning memoryChildren read the same stories rated their shared reading time higher than those read different booksThe authors note their findings have implications for preschool children. They note that napping should be encouraged in this age group. Additionally, preschool teachers and parents should use the time before naps to expose children to word learning and other key cognitive development tasks.This research is an important trial to take advantage of a growing knowledge base on sleep and learning.Readers with more interest in this topic can access the free full-text manuscript by clicking on the citation link below.Photo of osprey with fish over gull is from the author's files.Follow the author on Twitter at WRY999Williams SE, & Horst JS (2014). Goodnight book: sleep consolidation improves word learning via storybooks. Frontiers in psychology, 5 PMID: 24624111... Read more »

Williams SE, & Horst JS. (2014) Goodnight book: sleep consolidation improves word learning via storybooks. Frontiers in psychology, 184. PMID: 24624111

March 18, 2014
11:46 AM
500 views

Short Sleep Duration in Children with Autism

by William Yates, M.D. in Brain Posts

Parents of children with autism and autism spectrum disorder commonly report sleep problems in their child.However, there have been few prospective systematic studies of sleep in this disorder.Joanna Humphreys from Canada and colleagues from England recently published an important manuscript addressing this topic.They used data from the Avon Longitudinal Study of Parents and Children. This data set includes prospective data collected from a cohort of over 14,000 children born between April 1991 and December of 1992.Parents in this study completed a detailed sleep questionnaire on their child eight times between 6 months to 12 years of age.Eighty six children in the cohort were identified as having a clinical diagnosis of autism or autism spectrum disorder based on medical record and school special education review.The parental sleep reports of the autism/autism spectrum cohort were compared to the reports from age-matched children without autism. The key findings from the study were:During infancy (six month sleep report) there was no difference in sleep duration between those with autism and controlsBy 30 months of age, children who would go on to develop autism showed a reduction in total sleep time of between 17 and 43 minutes per nightThis shorter sleep duration persisted from 6 months of age to 11 months of ageFrequent night time awakening (3 or more times per night) was present in 6 to 11% of the children with autism between 5 and 10 years of age compared to less than 1% of the control childrenThe authors note their results are consistent with a growing body of research linking autism with disturbance of the biological clock or circadian rhythm. This research includes evidence of reduced blood melatonin in autism. Additionally, several clinical trials have found bedtime oral melatonin effective in reducing sleep latency and increasing sleep duration in this population.The current study is limited by use of parental report measures. Direct sleep data from actigraphy or polysomnography (sleep study) was not available.Nevertheless, this is an important study. Readers with more interest in this research can access the free full text manuscript by clicking on the link below.Photo of skimmer birds in flight from the author's files.Humphreys JS, Gringras P, Blair PS, Scott N, Henderson J, Fleming PJ, & Emond AM (2014). Sleep patterns in children with autistic spectrum disorders: a prospective cohort study. Archives of disease in childhood, 99 (2), 114-8 PMID: 24061777... Read more »

Humphreys JS, Gringras P, Blair PS, Scott N, Henderson J, Fleming PJ, & Emond AM. (2014) Sleep patterns in children with autistic spectrum disorders: a prospective cohort study. Archives of disease in childhood, 99(2), 114-8. PMID: 24061777

March 17, 2014
11:10 AM
417 views

Brain Gray Matter Volumes in Primary Insomnia

by William Yates, M.D. in Brain Posts

Chronic primary insomnia is a sleep disorder characterized by delayed sleep onset, reduced total sleep duration and fatigue on morning awakening.In addition, by definition chronic primary insomnia cannot be due to a primary medical or psychiatric disorder. Some patients with chronic primary insomnia also demonstrate subjective and objective impairment in concentration and memory.Eun Yeon Joo and colleagues from South Korea recently published an analysis of brain structural features in 27 subjects with chronic primary insomnia compared to 27 control subjects without a sleep disorder.All case subjects in the study underwent a sleep study using polysomnography. The case subjects were 90% female and showed significant differences in multiple sleep parameters compared to an age and gender matched control group:Pittsburgh Sleep Quality Index Scores: 19.1 vs 3.2Total sleep time: 349 minutes vs 391 minutesSleep latency (Time to fall asleep): 26 minutes vs 9 minutesREM latency (Time to first REM period) 141 minutes vs 85 minutesSleep efficiency (Total sleep time/time in bed) 81% vs 89%Cases and controls completed magnetic resonance imaging using a 1.5 Tesla scanner. Subjects with chronic primary insomnia showed widespread deficits in gray matter concentration and volumes compared to controls.These deficits involved diverse brain regions including multiple areas of the frontal cortex, precentral cortex, superior temporal cortex and the cerebellum.Using multiple regression analysis, deficits in specific regions correlated with specific insomnia markers:Insomnia Severity Index: middle frontal gyrusSleep latency and REM sleep latency: precentral gyrusWake time after sleep onset: middle frontal gyrus, precentral gyrus and inferior frontal gyrusThe authors note deficits in gray matter volume in both the left and right temporal cortex might contribute to insomnia. Gray matter deficits in these auditory regions may contribute to an auditory hyperarousal increasing awakening with nocturnal noise stimuli.The authors note they findings cannot determine whether gray matter deficits precede or are a consequence of chronic primary insomnia.Subjects had suffered from chronic primary insomnia for an average of 7.6 years. Additionally, as a group they demonstrated reduction in performance on several neuropsychological measures of attention, memory, language and executive function.The take home clinical message from this study is that primary chronic insomnia is an important sleep disorder. Early detection and intervention may reduce gray matter reductions and reduce cognitive decline. Prospective longitudinal studies are needed to better understand brain structural and function correlates of this sleep disorder.Readers with more interest in this research can access the free full-text manuscript by clicking on the link in the citation below.Follow the author on Twitter WRY999 Photo of willet on the seashore from the author's files.Joo EY, Noh HJ, Kim JS, Koo DL, Kim D, Hwang KJ, Kim JY, Kim ST, Kim MR, & Hong SB (2013). Brain Gray Matter Deficits in Patients with Chronic Primary Insomnia. Sleep, 36 (7), 999-1007 PMID: 23814336... Read more »

Joo EY, Noh HJ, Kim JS, Koo DL, Kim D, Hwang KJ, Kim JY, Kim ST, Kim MR, & Hong SB. (2013) Brain Gray Matter Deficits in Patients with Chronic Primary Insomnia. Sleep, 36(7), 999-1007. PMID: 23814336

March 13, 2014
12:11 PM
508 views

Outcome in REM Sleep Behavior Disorder

by William Yates, M.D. in Brain Posts

This is the second in series of posts examining recent research in sleep and the brain.Rapid eye movement (REM) sleep behavior disorder is a complex sleep problem seen primarily in older adults.REM, or dream sleep, typically occurs with atonia. Atonia is the temporary state of muscle paralysis. This prohibits muscular activity or acting out during dream states.With REM sleep behavior disorder, atonia is not present with REM sleep resulting in motor restlessness, agitation and occasionally violent behavior towards bed partners.REM sleep behavior disorder is known to be a potential marker for risk of neurodegenerative disorders including Lewy body dementia and Parkinson's disease. Few studies systematically examine the rates of neurodegenerative disorders following the diagnosis of REM sleep behavior disorder. Iranzo and colleagues recently published the results of a study of 174 subjects with REM sleep behavior disorder followed for up to 14 years after the diagnosis. Subjects at baseline diagnosis had dream-enacting behavior and a sleep lab assessment of increased muscular activity during REM sleep. No neurodegenerative disorders were present at baseline. Mean age of the subjects at baseline was 69 years.Rates of emergence of a neurodegenerative disorder were high and increased during follow-up:Five years: 33% had a neurodegenerative disorderTen years: 76% had a neurodegenerative disorderFourteen years: 91% had a neurodegenerative disorderThe most common neurodegenerative disorders in the cohort included dementia with Lewy bodies (37%), Parkinson's disease (28%) and mild cognitive impairment (15%).The authors note their study is the largest study of outcome for REM sleep behavior disorder published to date.Dementia with Lewy bodies and Parkinson's disease share pathological features involving the alpha-synuclein protein. The current study supports REM sleep behavior disorder as a potential biomarker for alpha-synuclein protein brain disorders. This biomarker may aid in early diagnosis of Lewy body dementia and Parkinson's disease providing a pathway to early interventions. Readers with more interest in this research manuscript can access a free full-text article by clicking on the citation link below.Follow the author on Twitter at WRY999.Photo of red-shouldered hawk in flight is from the author's files.Iranzo A, Fernández-Arcos A, Tolosa E, Serradell M, Molinuevo JL, Valldeoriola F, Gelpi E, Vilaseca I, Sánchez-Valle R, Lladó A, Gaig C, & Santamaría J (2014). Neurodegenerative Disorder Risk in Idiopathic REM Sleep Behavior Disorder: Study in 174 Patients. PloS one, 9 (2) PMID: 24587002... Read more »

Iranzo A, Fernández-Arcos A, Tolosa E, Serradell M, Molinuevo JL, Valldeoriola F, Gelpi E, Vilaseca I, Sánchez-Valle R, Lladó A.... (2014) Neurodegenerative Disorder Risk in Idiopathic REM Sleep Behavior Disorder: Study in 174 Patients. PloS one, 9(2). PMID: 24587002

March 11, 2014
11:09 AM
496 views

Depression-related Sleep Abnormalities Vary By Age

by William Yates, M.D. in Brain Posts

This month I will be focusing on sleep and the brain. The importance of sleep to normal and abnormal brain functioning is receiving increased research attention.A variety of sleep abnormalities have been described in major depression and bipolar affective disorder. Depression has been linked to delayed sleep onset, reduced time to first rapid eye movement (REM) period, reduced sleep efficiency and disruption of the circadian rhythm of sleep.Sleep physiology also varies throughout the lifespan. Puberty produces a delay in the sleep-wake cycle while older age is associated with a earlier sleep-wake cycle and reduced total sleep time.Robillard and colleagues recently published a study designed to tease out the effects of depression on sleep across the life cycle. The key elements of the design of their study included the following components:Subjects: 238 treatment-seeking individuals with a lifetime history of mood disorder ranging in age from 12 to 90 years of ageProcedures: Subjects wore an activity watch (actigraphy) for up to 22 days and completed sleep diaries. Additionally, subjects completed the Hamilton Depression Rating Scale a measure of current severity of depression symptomsOutcome variables: sleep onset time, sleep offset time, total time in bed, total sleep time, time awake after sleep onset and sleep efficiency (time asleep divided by time in bed). Additionally, five circadian rhythm parameters were estimated from the dataData analysis: Outcome variables were examined using two-way ANOVA with depression severity and age category as covariatesThe study found significant differences in the depression-related sleep parameters by age and depression severity:Younger age effects: Depression severity in younger adolescents and younger adults was associated with later sleep onset and offset, longer time in bed, longer time awake after sleep onset and lower sleep efficiencyOlder age effects: Depression severity in older adults was associated with reduced circadian rhythm strengthEffects found in all age groups: Depression severity was associated with disruption of sleep consolidationThe authors note in their discussion that sleep offset (later morning awakening) is associated with age and depression severity and "may be especially sensitive to the additive effects of age and depression". This study is limited to use of actigraphy data and did not include more accurate polysomnography (sleep studies). Additionally, the study did not include a non-depressed control sample. Finally, there is limited description of psychotropic drug use in the sample a potentially confounding factor. Nevertheless, this is an important study that helps tease out the effects of depression compared to the effects of age on sleep. Depression appears to adversely effect sleep function across the life cycle. Sleep function can be a valuable tool for assessment and monitoring treatment in mood disorders.Readers with more interest in this research can access the free full-text article by clicking on the link citation link below.Photo of a red shouldered hawk is from the author's files.Follow the author on Twitter @WRY999Robillard, R., Naismith, S., Smith, K., Rogers, N., White, D., Terpening, Z., Ip, T., Hermens, D., Whitwell, B., Scott, E., & Hickie, I. (2014). Sleep-Wake Cycle in Young and Older Persons with a Lifetime History of Mood Disorders PLoS ONE, 9 (2) DOI: 10.1371/journal.pone.0087763... Read more »

Robillard, R., Naismith, S., Smith, K., Rogers, N., White, D., Terpening, Z., Ip, T., Hermens, D., Whitwell, B., Scott, E.... (2014) Sleep-Wake Cycle in Young and Older Persons with a Lifetime History of Mood Disorders. PLoS ONE, 9(2). DOI: 10.1371/journal.pone.0087763

March 3, 2014
09:14 AM
421 views

Behavioral Weight-Loss in Serious Mental Illness

by William Yates, M.D. in Brain Posts

Individuals with schizophrenia or bipolar disorder are at higher risk for obesity.This risk may be related to physical inactivity, diet or the weight gain commonly associated with psychotropic drug use.Few clinical trials for weight loss have targeted individuals with serious mental illness (SMI). This population may pose specific challenges in recruitment, adherence and outcome.Gail Daumit and colleagues recently published a randomized clinical trial of behavioral weight loss in a cohort with SMI.This study was published in the journal New England Journal of Medicine.A total of 291 overweight or obese subjects with SMI were recruited for a randomized controlled trail of behavioral intervention for weight loss. The components of the behavioral intervention included the following elements:A conceptual framework built on social cognitive and behavioral management theoriesGroup weight loss sessionIndividual weight loss sessionsGroup exercise sessionsDiet instruction targeted to reduce added sugar, increase fruit and vegetable consumptionThe behavioral intervention demonstrated a modest but progressive loss of weight over the 18 months of the study. The mean weight loss in the intervention group was about 7 pounds compared to no weight loss in the control group.After 18 months, 38 % of the intervention group lost 5% of body weight or more compared to 23% of the control group. At the same time point 19% of the intervention group lost 10% of body weight or more compared to only 7% of the control group.Retention rates were high in the study and may relate to the fact that subjects were recruited from community mental health centers. Subjects in the study were already involved in a psychiatric rehabilitation program and the behavioral weight loss intervention was an add-on component.Eighty percent of the subjects in this trial had a primary diagnosis of schizophrenia, schizoaffective disorder or bipolar disorder. On average, the were taking 3 psychotropic drugs during the study and 90% were receiving antipsychotic drugs.This study supports the use of behavioral weight loss intervention in obese SMI populations. Such programs may be most effective when integrated with an existing psychiatric rehabilitation program.Readers with more interest in this research can access the free full text manuscript by clicking on the PMID link below.Photo of flamingo from the San Antonio zoo is from the author's files.Follow the author on Twitter WRY999.Daumit GL, Dickerson FB, Wang NY, Dalcin A, Jerome GJ, Anderson CA, Young DR, Frick KD, Yu A, Gennusa JV 3rd, Oefinger M, Crum RM, Charleston J, Casagrande SS, Guallar E, Goldberg RW, Campbell LM, & Appel LJ (2013). A behavioral weight-loss intervention in persons with serious mental illness. The New England journal of medicine, 368 (17), 1594-602 PMID: 23517118... Read more »

Daumit GL, Dickerson FB, Wang NY, Dalcin A, Jerome GJ, Anderson CA, Young DR, Frick KD, Yu A, Gennusa JV 3rd.... (2013) A behavioral weight-loss intervention in persons with serious mental illness. The New England journal of medicine, 368(17), 1594-602. PMID: 23517118

February 24, 2014
08:17 AM
535 views

Fish Consumption and Brain Health

by William Yates, M.D. in Brain Posts

I have previously examined outcomes for MRI changes known as brain white matter hyperintensities (WMHI).WMHIs are noted in a minority of adults and are not completely understood. The changes are considered subclinical in nature, meaning they do not reach a threshold for medical significance.However, these subclinical WMHI are linked to higher rates of premature cognitive decline. Absence of WMHI is seen by some as one marker of brain health.Jyrki Virtanen and colleagues from Finland recently examined the relationship between WMHI and other subclinical brain abnormalities in 3660 adults 65 years of age and older. A subset of subjects had a repeat MRI 5 years later.MRI scans for this cohort were examined for several subclinical brain abnormalites including white matter grade, brain atrophy, ventricular size and sulcal size.Subjects also completed blood levels of omega-3 polyunsaturated fatty acids (PUFA). Omega-3 PUFAs are markers of dietary intake for fish and fish oils and higher levels have been linked to improved brain health.Subjects were grouped into quartiles of omega-3 level from highest to lowest.The main findings from the study included:High quartile omega-3 subjects had lower rates of subclinical brain infarct (odds ratio 0.60)Higher levels of long-chain omega-3 PUFAs were associated with high brain white matter gradeOmega-3 PUFA levels were not associated with other subclinical brain abnormalities (sulcal size, ventricular size or brain atrophy grades)The authors concluded "among older men and women, plasma phospholipid long-chain omega-3 PUFAs, and in particular DHA, were associated with specific findings consistent with better brain health, including lower risk of prevalent subclinical (lacunar) infarcts, better white matter grade, and lower risk of worsening white matter".The authors note that dietary omega-3 PUFA is found in tuna and other fatty fishes but not in fried fish sources such as fish sticks.They also note that the omega-3 PUFA docosahexanoic acid or DHA may "be most relevant for brain health". Correlational studies always need to be interpreted carefully as correlation does not equal causation.Nevertheless, this study adds to growing evidence of the value of regular tuna, sardines and salmon in a healthy diet.Readers with more interest in this study can access the free full-text manuscript by clicking on the PMID link below.Photo of great blue heron with fish is from the author's files.Follow the author on Twitter WRY999.Virtanen JK, Siscovick DS, Lemaitre RN, Longstreth WT, Spiegelman D, Rimm EB, King IB, & Mozaffarian D (2013). Circulating omega-3 polyunsaturated fatty acids and subclinical brain abnormalities on MRI in older adults: the Cardiovascular Health Study. Journal of the American Heart Association, 2 (5) PMID: 24113325... Read more »

Virtanen JK, Siscovick DS, Lemaitre RN, Longstreth WT, Spiegelman D, Rimm EB, King IB, & Mozaffarian D. (2013) Circulating omega-3 polyunsaturated fatty acids and subclinical brain abnormalities on MRI in older adults: the Cardiovascular Health Study. Journal of the American Heart Association, 2(5). PMID: 24113325

February 20, 2014
09:16 AM
524 views

Exercise as a Treatment Following Stroke

by William Yates, M.D. in Brain Posts

Exercise appears to be therapeutic in treatment of a variety of medical conditions.However, the relative magnitude of the effect of exercise is less well documented. Comparing the magnitude of the therapeutic effect of exercise with that of common drug interventions can be quite informative.Such comparisons provide insight into the relative value of exercise and the role of exercise in comprehensive treatment planning.Huseyin Naci and John Ioannidis recently published a study of the comparative effectiveness of exercise in the British Medical Journal.In this study, a meta-analysis was completed of randomized controlled trials with a primary outcome of mortality risk. Four exercise trials and twelve drug trials were examined and compared across four common diseases (drug treatment reference):Coronary heart disease (statins, beta blockers, ACE inhibitors, antiplatelet therapy)Stroke (anticoagulants, antiplatelets)Heart failure (ACE inhibitors, diuretics, beta blockers, angiotensin receptor blockers)Diabetes prevention (alpha glucosidase inhibitors, thiazolidinedones, biguanides, ACE inhibitors, glinides)The findings from this analysis are quite informative. Exercise post-stroke had the biggest comparative effectiveness compared to both anticoagulant or antiplatelet therapy. The exercise risk reduction estimate for post-stroke mortality was 91% (95% confidence interval 38% to 99%). Anticoagulants and antiplatelet therapy failed to demonstrate a statistically significant mortality reduction.Mortality risk reduction for coronary heart disease and prediabetes were modest and failed to reach statistical significance. Exercise was estimated to reduce mortality risk during follow up for heart failure by about 20%, but this effect was much less than the most effective drug treatment of diuretics (80% risk reduction).The study highlights the relative importance of exercise rehabilitation following stroke. Other current interventions have limited effects and exercise rehabilitation may currently be the most effective treatment available.Readers with more interest in this study can access the free full-text manuscript by clicking on the PMID link below.Photo of roseatted spoonbills at sunset is from the author's files.Follow the author on Twitter WRY999.Naci H, & Ioannidis JP (2013). Comparative effectiveness of exercise and drug interventions on mortality outcomes: metaepidemiological study. BMJ (Clinical research ed.), 347 PMID: 24473061... Read more »

Naci H, & Ioannidis JP. (2013) Comparative effectiveness of exercise and drug interventions on mortality outcomes: metaepidemiological study. BMJ (Clinical research ed.). PMID: 24473061

February 17, 2014
08:02 AM
539 views

Acute Brain Response to Exercise in Healthy Young Adults

by William Yates, M.D. in Brain Posts

This month I have been reviewing recent research on the effects of exercise on the brain.Exercise appears to have both acute and chronic effects on brain physiology and function. Newer imaging techniques provide sensitive tools to study exercise and the brain.Bradley Macintosh and colleagues recently paired an aerobic exercise task with measurements of cerebral blood flow and blood oxygen utilization.The key elements of the design of their experiment included the following elements:Subjects: Sixteen healthy adults (ten women and six men) between the ages of 20 and 35 years of ageExercise task: 25 minutes of exercise on a recumbent bike with 20 minutes at 70% of estimated maximum heart rateImaging protocol: Subjects had brain imaging studies before exercise and 10 and 40 minutes following exercise using cerebral blood flow and functional magnetic resonance imaging using a sustained attention task.Statistical analysis: Paired t-tests on behavioral and imaging data were use to compare baseline and post-exercise performanceThe analysis found specific region variations in the brain following exercise. The main findings from the study included:Cerebral blood flow: Gray matter cerebral blood flow decreased at 10 minutes after exercise while white matter cerebral blood flow increased at 40 minutes compared to baseline. The brain hippocampus and insula showed significant reduction in perfusion post-exercise. The left medial postcentral gyrus brain region demonstrated a reverse trend with increased perfusion post-exercise.BOLD MRI: Most brain regions showed no BOLD response changes with exercise. However, a region of the left parietal lobe known as the operculum had reduced BOLD activation following exercise.Cognitive Testing: Subjects showed no differences in measures of attention including error rates and reaction time.The authors concluded that there are acute cerebral blood flow effects on the brain with exercise without significant brain activation changes. They note these cerebral blood flow changes may contribute to a neuroplasticity effect for exercise.They also noted the increased white matter perfusion with exercise may contribute to improvements in white matter integrity. Previous studies of chronic exercise have noted improved white matter connectivity.This is an important study documenting the acute brain response to exercise. Aerobic exercise seems to provide for a brain work out as well as a cardiovascular and musculoskeletal work out.Readers with more interest in this study can access the free full-text manuscript by clicking on the PMID link in the citation below.Photo of a bottlenose dolphin off Fulton, TX is from the author's files.Follow the author on Twitter at WRY999.Macintosh BJ, Crane DE, Sage MD, Rajab AS, Donahue MJ, McIlroy WE, & Middleton LE (2014). Impact of a single bout of aerobic exercise on regional brain perfusion and activation responses in healthy young adults. PloS one, 9 (1) PMID: 24416356... Read more »

Macintosh BJ, Crane DE, Sage MD, Rajab AS, Donahue MJ, McIlroy WE, & Middleton LE. (2014) Impact of a single bout of aerobic exercise on regional brain perfusion and activation responses in healthy young adults. PloS one, 9(1). PMID: 24416356

February 13, 2014
07:47 AM
522 views

Weight Training for Type 2 Diabetes Prevention in Women

by William Yates, M.D. in Brain Posts

This is the fifth in a series of articles examining research findings on exercise and the brain.Type 2 diabetes and obesity can contribute to risk for early cognitive decline and dementia.Strategies that reduce risk of Type 2 diabetes may indirectly contribute to brain health.Aerobic exercise and weight loss are known to reduce Type 2 diabetes risk.However, the role of weight training on diabetes risk is less clear.A recent study has shed some light on the potential role for weight training as an independent prevention strategy.Grontved and colleagues examined self-reported exercise habits and risk of developing type 2 diabetes in the Nurses' Health Study cohort. In this cohort nearly 100,000 nurses in the U.S. complete behavior and health information in a prospective design.Subjects reported their average weekly time spent in three types of exercise categories:Resistance exercise (weight training)Low intensity exercise activitives (stretching, yoga)Aerobic physical activities (brisk walking, jogging, running etc)At baseline subjects in this study were free of a diagnosis of diabetes. During four years of follow up, 3491 women developed type 2 diabetes. These new-onset type 2 diabetes cases were compared to control women who did not develop diabetes.The primary finding from this study is that weight training was independently correlated with lower risk of developing type 2 diabetes. Subjects participating in weight training at least 60 minutes or more per week had a 25% to 40% reduction in type 2 diabetes rates.Subjects who paired 150 minutes per week of aerobic exercise with 60 minutes per week of resistance training had a 67% reduction in risk for a new diabetes diagnosis over the follow up period.An additional finding was a reduced risk for type 2 diabetes for the low intensity exercise activity.These effect sizes for exercise and type 2 diabetes risk are pretty impressive. The authors point out there are several mechanisms potentially explaining a reduction of type 2 diabetes risk with weight training. Maintaining muscle mass promotes muscle glucose utilization, glycogen lysis and regulation of insulin signaling proteins. The authors conclude combining aerobic activity with resistance training is a promising combination for reducing type 2 diabetes risk in women. The effect of this combination appears more beneficial for overweight and obese women.Readers with more interest in this research can access the free full-text manuscript by clicking on the PMID link below.Photo of tricolor heron is from the author's files.Follow the author on Twitter WRY999.Grøntved A, Pan A, Mekary RA, Stampfer M, Willett WC, Manson JE, & Hu FB (2014). Muscle-Strengthening and Conditioning Activities and Risk of Type 2 Diabetes: A Prospective Study in Two Cohorts of US Women. PLoS medicine, 11 (1) PMID: 24453948... Read more »

Grøntved A, Pan A, Mekary RA, Stampfer M, Willett WC, Manson JE, & Hu FB. (2014) Muscle-Strengthening and Conditioning Activities and Risk of Type 2 Diabetes: A Prospective Study in Two Cohorts of US Women. PLoS medicine, 11(1). PMID: 24453948

February 11, 2014
08:33 AM
460 views

Exercise and a Healthy Hippocampus in Middle Age

by William Yates, M.D. in Brain Posts

The beneficial effects of exercise on the brain has received significant research attention in children and older adults.Fewer research studies target young and middle aged adults.William Killgore and colleagues recently addressed this population in a study published in Scientific Reports.They preformed a cross-sectional correlation study of brain structure and self-reported exercise habits.Sixty one men and women between the ages of 18 and 45 years of age were recruited for the study.Subjects were recruited from the Boston metropolitan area and were excluded if they had a significant medical, neurological or psychiatric problem. Additional exclusion criteria included history of severe head injury or current use of psychotropic drugs.Subjects were questioned about the level of physical activity. Seventy five percent of the subjects endorsed regular physical activity with an average of 2.3 sessions per week lasting an average of 45 minutes.Brain structural volumes were measured via structural magnetic resonance imaging using a 3.0 Tesla scanner. The key finding from their study was a significant positive correlation between minutes of weekly exercise and size of the regions of the right hippocampus.The hippocampus was a specific region of interest expressed before the analysis as this region has previously been associated with exercise effects. The hippocampus plays a key role in memory function.Extending their analysis outside of the original hippocampal regions, the authors noted a additional positive correlation between minutes of exercise per week and greater gray matter volume in the left posterior insula region.The authors note the insular cortex is linked to central control of cardiovascular function. Additionally, the insula is involved in modulation of emotions, appetite and motivation. This region may play a role in the beneficial effects of exercise on mood and weight regulation.This is an important research study. However, it is limited to a cross-sectional correlation design. Correlation does not equal causation. Additionally, self-report exercise levels may differ significantly from actual exercise levels producing a potential bias.Nevertheless, this study adds to what we know about exercise and the brain. The results support an important role for exercise in brain hippocampal health throughout the lifespan including middle age.Readers with more interest in the study can access the free full-text article by clicking on the PMID link in the citation below.Photo of a snowy egret near Port Aransas, TX is from the author's files.Follow the author on Twitter at WRY999.Killgore WD, Olson EA, & Weber M (2013). Physical exercise habits correlate with gray matter volume of the hippocampus in healthy adult humans. Scientific reports, 3 PMID: 24336512... Read more »

Killgore WD, Olson EA, & Weber M. (2013) Physical exercise habits correlate with gray matter volume of the hippocampus in healthy adult humans. Scientific reports, 3457. PMID: 24336512

February 5, 2014
10:18 AM
533 views

Exercise Trial for Cognitive Impairment in Older Adults

by William Yates, M.D. in Brain Posts

Current drug treatments for cognitive impairment and dementia show limited effectiveness.Alternative adjunctive treatments in those with early cognitive impairment are needed.In a previous post, I outlined a review of what we know about exercise and cognition in elderly populations.An additional study is relevant to this topic and important.Takao Suzuki and colleagues in Japan conducted a randomized controlled trial of multicomponent exercise in older adults with evidence of mild cognitive impairment.The key elements in the design of this study included:Subjects: Community dwelling adults with a Clinical Dementia Rating of 0.5 diagnosed with mild cognitive impairment confirmed with neuropsychological assessmentIntervention: biweekly sessions lasting 90 minutes for 6 months with aerobic exercise, strength training, balance and dual-task exercises versus control intervention of attendance at two educational classesOutcome measures: Alzheimer's Disease Assessment Scale-Cognitive, Minimental State scores, logical memory scores and brain volume measures on magnetic resonance imagingThe Japanese research team found a significant benefit for the exercise group over the control group at 6 months that was limited to subjects with amnestic minimal cognitive impairment including:Less progression of cognitive impairment on the Minimental State examBetter performance on the logical memory testReduction in the level of whole brain cortical atrophy during the intervention periodThere did not appear to be a benefit for exercise in subjects with non-amnestic types of mild cognitive impairment.Of note, the study team found two predictors of exercise response: lower baseline cholesterol level and higher baseline level of the hormone brain derived neurotrophic factor (BDNF).The authors note high total cholesterol levels and other dyslipidemias may limit the beneficial effect of exercise. It is unknown if pairing cholesterol lowering drugs with exercise might reduce this limitation.BDNF is known to be important in neuroplasticity. The author's finding suggests a potential interaction between BDNF and the beneficial effect of exercise on cognition in the elderly.Readers with more interest in this subject can access the free full-text article by clicking on the PMID link below.Photo is from the author's files.Follow the author on Twitter WRY999Suzuki T, Shimada H, Makizako H, Doi T, Yoshida D, Ito K, Shimokata H, Washimi Y, Endo H, & Kato T (2013). A randomized controlled trial of multicomponent exercise in older adults with mild cognitive impairment. PloS one, 8 (4) PMID: 23585901... Read more »

Suzuki T, Shimada H, Makizako H, Doi T, Yoshida D, Ito K, Shimokata H, Washimi Y, Endo H, & Kato T. (2013) A randomized controlled trial of multicomponent exercise in older adults with mild cognitive impairment. PloS one, 8(4). PMID: 23585901

February 3, 2014
10:12 AM
607 views

Aging, Exercise and Brain Plasticity

by William Yates, M.D. in Brain Posts

Over the next month, I will be focusing on the effects of exercise on the brain.This topic is important for several reasons. Exercise appears to play a preventive role in the effects of brain aging in normal adults.Exercise may aid in the slowing of progression of brain disorders such as Alzheimer's disease and Parkinson's disease.Exercise is a promising adjunct to treatment of a variety of other brain disorders including depression and anxiety disorder.For this post, I want to highlight what is currently known about this topic. Kirk Erickson and colleagues at the University of Pittsburgh recently published a relevant review in the journal Dialogues in Clinical Neuroscience.Here are my notes on some of the key points in their review:Animal model studies: Active rats using a running wheel outperform sedentary rats on learning and memory tasks. This enhanced performance appears related to increased size and function of the hippocampus with exercise. The biological mechanism for this effect is unclear. However, animal models have show exercise influences gene expression, increases brain vasularization and stimulates neuron development. Exercise also promotes brain plasticity possibly through positive effects on hormones and neurotransmitters (i.e. brain-derived neurotrophic factor and serotonin)Physical activity and human cognition: Cross-sectional studies show that midlife and late life physical activity is linked to better cognitive function at older ages. Prospective randomized trials of moderate exercise intervention confirm improved executive function in older adults. Brain regions influenced by physical activity: Rodent studies show enhanced structure and function of brain frontal/prefrontal cortex, hippocampus and basal ganglia with aerobic exercise. Fit individuals show reduced rates of age-related brain atrophy in the hippocampus. Structural brain changes with exercise are accompanied by functional performance. Functional brain imaging studies show increased exercise increases brain activation in the dorsolateral prefrontal cortex (see figure), the parietal cortex and parietal regions. Beneficial effects of exercise on the brain extend to enhanced connectivity including preservation of the default mode network.Exercise effects on depression in older adults: Elderly subjects with depression appear to benefit when exercise is added to antidepressant drug treatment. In one study, 55% of depressed elderly subjects had a clinical depression response to moderate exercise (walking program) plus antidepressant treatment compared to a response rate of only 33% in those treated with antidepressants alone. There is some emerging evidence that weight training (progressive resistance training) improves depression in adults 60 and older. Exercise paired with social interaction may be a promising non-drug approach to depression treatment.The authors note there are many questions about exercise effects on cognition. The exact dose-response relationship is unclear. Elderly subjects may have significant barriers to increase physical activity including degenerative arthritis, balance problems and vulnerability to exercise-related injuries.Future research will answer some of these questions.In the next few posts, I will spend more time on some key individual studies of exercise and the brain.Individuals with more interest in this topic can access the free full-text article by clicking on the PMID link on the citation below.Figure is an iPad screen shot of the prefrontal cortex from the app 3D Brain.Follow the author on Twitter at WRY999Erickson KI, Gildengers AG, & Butters MA (2013). Physical activity and brain plasticity in late adulthood. Dialogues in clinical neuroscience, 15 (1), 99-108 PMID: 23576893... Read more »

Erickson KI, Gildengers AG, & Butters MA. (2013) Physical activity and brain plasticity in late adulthood. Dialogues in clinical neuroscience, 15(1), 99-108. PMID: 23576893

January 27, 2014
08:09 AM
507 views

Vagal Nerve Blockade in Type 2 Diabetes Clinical Trial

by William Yates, M.D. in Brain Posts

One of the potential advances in diabetes management is modulation of the vagus nerve.The vagus nerve appears to influence a variety of physiological factors related to calorie intake, metabolism and blood glucose control.Severing the vagus nerve (vagotomy) results in weight loss and increased satiety but can cause gastric retention.An implantable device that can intermittently block vagal nerves may provide favorable metabolic modulation without the adverse effects of vagotomy.An initial study of vagal blockade in morbid obesity was published in 2012.This study was conducted in the U.S. and Australia with 503 morbid obese subjects with a mean BMI of 41.All subjects had a vagal blockade device implanted but only 2/3 of them had active vagal blockade provided during the 12 month study.Active vagal blockade subjects showed a 17% reduction in weight over the study but this was not statistically different than the control group that had a 16% reduction in body weight.A second trial published in 2013 looked at the response of 28 obese subjects with type 2 diabetes to vagal blockade.This smaller study did not include a control group. This limits the generalizability of the study. Here are the key findings in the type 2 diabetes trial:Weight loss: 25% body weight loss over 12 monthsHemaglobin A1C: declined by 1.0Blood pressue: subjects with hypertension showed an 8 mmHg mean arterial pressure at 12 monthsIt is clear there is more need for clinical research to determine the potential clinical utility of implanting a vagal nerve device in obese and diabetic individuals.Any intervention that promotes weight loss is beneficial to metabolic and blood pressure measures.Implanting a vagal nerve device may have significant placebo effects. It is dramatic intervention and in the second study was accompanied by significant counseling and clinical monitoring. Separating the effect of the device from the effect of the other components of the trial is difficult.Vagal blockade is relatively straightforward, but it is not without risk. Similar to implanting a pacemaker, the surgery has a relative low rate of serious complication.Given the mixed findings to date, this approach can not be currently endorsed as a standard treatment approach. Future trials may provide evidence of merit in specific clinical populations.Readers with more interest in the diabetes trial can access the free full-text article by clicking on the PMID link below.Disclosure: Brain Posts does not recommend specific medication, diets or surgical treatment options. Personal decisions about medical interventions need to be made in consultation with a personal physician.Photo of downy woodpecker is from the author's files.Follow the author on Twitter WRY999.Shikora S, Toouli J, Herrera MF, Kulseng B, Zulewski H, Brancatisano R, Kow L, Pantoja JP, Johnsen G, Brancatisano A, Tweden KS, Knudson MB, & Billington CJ (2013). Vagal blocking improves glycemic control and elevated blood pressure in obese subjects with type 2 diabetes mellitus. Journal of obesity, 2013 PMID: 23984050Sarr MG, Billington CJ, Brancatisano R, Brancatisano A, Toouli J, Kow L, Nguyen NT, Blackstone R, Maher JW, Shikora S, Reeds DN, Eagon JC, Wolfe BM, O'Rourke RW, Fujioka K, Takata M, Swain JM, Morton JM, Ikramuddin S, Schweitzer M, Chand B, Rosenthal R, & EMPOWER Study Group (2012). The EMPOWER study: randomized, prospective, double-blind, multicenter trial of vagal blockade to induce weight loss in morbid obesity. Obesity s... Read more »

Shikora S, Toouli J, Herrera MF, Kulseng B, Zulewski H, Brancatisano R, Kow L, Pantoja JP, Johnsen G, Brancatisano A.... (2013) Vagal blocking improves glycemic control and elevated blood pressure in obese subjects with type 2 diabetes mellitus. Journal of obesity, 245683. PMID: 23984050

Sarr MG, Billington CJ, Brancatisano R, Brancatisano A, Toouli J, Kow L, Nguyen NT, Blackstone R, Maher JW, Shikora S.... (2012) The EMPOWER study: randomized, prospective, double-blind, multicenter trial of vagal blockade to induce weight loss in morbid obesity. Obesity surgery, 22(11), 1771-82. PMID: 22956251

January 20, 2014
07:51 AM
533 views

Alternate Day Fasting for Weight Loss and Cardioprotection

by William Yates, M.D. in Brain Posts

I have previously commented on the alternate day fasting diet for weight loss. Studies have generally supported this strategy. Alternate day fasting restricts caloric intake to an evening meal of 25% of caloric needs every other day.On non-fasting days, dieters are encouraged to eat a typical diet without restriction.A recent randomized controlled trial of alternate day fasting has been published in Nutrition Journal.Krista Varady and colleagues from the University of Illinois designed a study of alternate day fasting the included the following key elements:Subjects: 32 adults with BMI between 20-29.9 randomized to 12 weeks of alternate day fasting versus controls who continued usual dietDiet Protocol: Alternate day fasting groups were provided a 400 to 600 calories meals that consisted of 55% calories from carbohydrate, 15% calories from protein and 30% calories from fatOutcome measures: Body weight, body fat mass, serum lipids, inflammatory marker CRP levels, adiponectin and leptin levels and measures of hunger and fullnessThis design is interesting for including normal weight individuals who might be interested in alternate day fasting for lipid control or reduction of inflammatory markers.The study had the following main findings:Weight loss: Alternate day fast weight loss exceeded controls (5.2 kg vs 0.5 kg)Fat mass loss: Alternate day fast fat mass exceeded controls (3.5% v 0.3%)Lipid changes: Total cholesterol in the fasting group dropped from a mean of 201 to 175 at week 12 but this was not statistically different than controls. Similarly, serum triglycerides droped from 109 to 87 mg/dl but this was not statistically different from controls.Inflammation: CRP levels decreased in fasting group but not controlsMetabolic markers: Adiponectin levels increased and leptin levels dropped in fasting group but not controls.The authors note their study suggests normal weight and overweight individuals appear to lose about one pound per week using alternate day fasting. Subjects fasting reported lower rates of fullness and satisfaction than controls early in this clinical trial. By the end of 12 weeks these ratings improved suggesting an adaptation to the diet.The authors note a weakness of this study is a small sample size with limited power to find differences between groups.The authors also note normal weight and overweight individuals (BMI 25 to 30) with hypelipidemia may benefit from a trial of alternate day fasting.Disclosure: Brain Posts does not recommend specific diets but only reviews and provides commentary on interesting research related to the brain. Any dietary change decisions need to be made on a personal basis with consultation from a physician.Readers with more interest in the study can access the free full text article by clicking on the PMID link below.Follow the author on Twitter WRY999.Photo of back yard squirrel is from the author's files.Varady KA, Bhutani S, Klempel MC, Kroeger CM, Trepanowski JF, Haus JM, Hoddy KK, & Calvo Y (2013). Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. Nutrition journal, 12 (1) PMID: 24215592... Read more »

Varady KA, Bhutani S, Klempel MC, Kroeger CM, Trepanowski JF, Haus JM, Hoddy KK, & Calvo Y. (2013) Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. Nutrition journal, 12(1), 146. PMID: 24215592

January 14, 2014
09:20 AM
388 views

Weight Loss Drug Combo Improves Sleep Apnea

by William Yates, M.D. in Brain Posts

Obesity is a risk factor for obstructive sleep apnea. Use of a positive airway pressure (PAP) device is the standard treatment for sleep apnea.However, PAP commonly is only moderately effective in reducing sleep disruption and day time fatigue. A significant number of individuals fail to use their PAP devices due to inconvenience or mask problems.Weight loss alone can improve sleep in those developing sleep apnea. Winslow and colleagues at the Kentucky Research conducted a randomized clinical trial of a recently FDA-approved weight loss drug combination in sleep apnea subjects. This combination drug includes phentermine 15 mg plus topiramate 92 mg and is taken once a day. Vivus, Inc is the pharmaceutical company marketing this combination drug in the U.S. under the brand name Qsymia.The key elements of the design of this study included:Subjects: 45 subjects with a diagnosis of moderate to severe obstructive sleep apnea with a BMI between 30 and 40.Intervention: 28 weeks of active drug combo or placebo with both groups receiving lifestyle modification counselingPrimary outcome measure: Apnea-hypopnea index (AHI). The AHI combines number of apneic episode with the degree of reduction of blood oxygen. Scores in the mild range are 5 to 15/hour, moderate 15 to 30/hour and severe over 30/hourSubjects receiving the active weight loss combination lost 11 kg (24 pounds) over the course of 28 week study statistically greater than the placebo group that lost 4.5 kg (10 pounds).At baseline, both drug and placebo group had a mean AHI in the severe range (44 to 45). Both groups had improvement in AHI scores at 8 weeks and 28 weeks. However, the active drug group had statistically lower AHI scores compared to placebo at 28 weeks (14.0 vs 27.)Two active drug subjects dropped out of the study. One had a recurrence of kidney stones with flank pain. Kidney stones are a known adverse effect associated with topiramate. A second active drug study subject dropped out due to irritability.One placebo subject experienced a stroke during the study and was withdrawn from the protocol. The authors note many studies using a dietary restriction intervention in sleep apnea show the benefits of weight loss in the disorder.The current study suggests use of phentermine 15 mg and topiramate 92 is an overall effective and relatively safe option in the treatment of sleep apnea associated with obesity.Decisions about selecting treatments for sleep apnea need to be done in consultation with a personal physician. This post is not an endorsement or recommendation for the use of weight loss drugs.Readers with more interest in this research can access the free full-text manuscript by clicking on the PMID link in the citation below.Photo of grey-crowned crane is from the authors files.Follow the author on Twitter at WRY999Winslow DH, Bowden CH, DiDonato KP, & McCullough PA (2012). A randomized, double-blind, placebo-controlled study of an oral, extended-release formulation of phentermine/topiramate for the treatment of obstructive sleep apnea in obese adults. Sleep, 35 (11), 1529-39 PMID: 23115402... Read more »

Winslow DH, Bowden CH, DiDonato KP, & McCullough PA. (2012) A randomized, double-blind, placebo-controlled study of an oral, extended-release formulation of phentermine/topiramate for the treatment of obstructive sleep apnea in obese adults. Sleep, 35(11), 1529-39. PMID: 23115402

January 13, 2014
09:48 AM
477 views

Low Carb-Mediterranean Diet Combo Sheds Fat in Trial

by William Yates, M.D. in Brain Posts

In keeping with this month's theme of obesity, the brain and weight loss I want to look at some clinical trial research.Brain Posts does not endorse any type of diet or weight loss pills or substances. Personal dietary and obesity medication use choices need to be made with a qualified health professional.However, I do post some dietary research that I find interesting. I have previously posted summaries of research related to the Mediterranean diet and beneficial cognitive and cardiovascular effects.I ran across a clinical obesity trial that combined a brief two-phase low carbohydrate diet on top of a Mediterranean diet maintenance.Antonio Paoli and colleagues from Italy and Greece conducted a clinical trial in obese subjects that included the following key components:Subjects: 68 subjects with mean BMI >30 between 25 and 65 years of age without diabetes or other severe chronic illnessDiet intervention: One clinical trial with two cycles of 20 days of a very low carbohydrate diet (30 grams carbohydrate per day), 20 days of low carbohydrate diet (90 grams carbohydrate per day) separated by 4 and 6 month Mediterranean diet maintenance phases (260 grams carbohydrate per day). During carbohydrate restriction cycles, subjects received vitamin, mineral and herbal supplementation.Measurements: Body weight, body fat, lipids, blood glucose, liver and kidney function and blood pressureThe results of clinical trial were pretty impressive. The average weight loss over 12 months was 16 kilograms or 35 pounds. That is an average 15% loss of body weight. Mean BMI dropped from 35.4 to 30.3. Mean percent body fat decreased from 43% to 34%.Metabolic parameters improved with weight loss over the trial with mean total cholesterol dropping from 193 to 180, fasting glucose from 102 to 95. Mean blood pressure dropped from 125 to 118 systolic.The authors note there is significant skepticism by medical professionals about very low carbohydrate diets. There is limited long-term efficacy and safety data. There were no serious adverse effects or deaths noted in the study from participation in the study. The completion rate was high suggesting subjects tolerated the trial.I researching this topic I found the blog and books by Dr. Steven Parker helpful. He is an internal medicine physician with quite a bit of interest in diabetes. He has written about very low carbohydrate diet trials in diabetes. You can find a link to his blog here.Again, this post is not an endorsement of the low carbohydrate or the Mediterranean. I am just pointing to some interesting research. Before making a decision to modify your diet, you should consult your physician before making any changes. Readers with more interest in the study in this blog can access the free full text manuscript by clicking on the citation PMID link below.Photo of foods in the Mediterannean Diet is from the author's files.Follow the author on Twitter at WRY999Paoli A, Bianco A, Grimaldi KA, Lodi A, & Bosco G (2013). Long term successful weight loss with a combination biphasic ketogenic mediterranean diet and mediterranean diet maintenance protocol. Nutrients, 5 (12), 5205-17 PMID: 24352095... Read more »

Paoli A, Bianco A, Grimaldi KA, Lodi A, & Bosco G. (2013) Long term successful weight loss with a combination biphasic ketogenic mediterranean diet and mediterranean diet maintenance protocol. Nutrients, 5(12), 5205-17. PMID: 24352095

January 9, 2014
10:58 AM
713 views

How the Body Blocks Effect of Exercise After Weight-Loss

by William Yates, M.D. in Brain Posts

Weight loss with aerobic physical activity does not correspond to a one-to-one relationship.For example if you started to burn 500 calories per day on a seven day per week basis, you might expect to lose one pound per week (3500 calories = one pound).But this is not the case. In a previous post, weight loss does occur with starting a physical exercise program but may be only 10-20% efficient over time.One way the body blocks exercise-induced weight loss is via adjustment in what is known as the activity energy expenditure or AEE.The AEE is the fraction of daily energy expenditure mainly due to the amount of daily physical activity.Bonomi and colleagues from the Netherlands recently conducted a nice study on this effect published in the manuscript PLOS One.The key elements of the design of their study included:Subjects: Seventy healthy subjects with a BMI >27 (mean BMI 38.3 at baseline)Protocol: Two weeks of weight maintenance, 12 weeks of 33% calorie restriction, two weeks of weight maintenanceMeasurements: Physical activity measure with accelerometer, AEE measurement using doubly-labelled water validated assay The key findings from the study:Subjects lost an average of 14 kilograms (31 pounds) over the 12 week diet restriction periodBoth resting metabolic rate and the AEE dropped by about 15% along with the weight lossTo offset these effects, subjects would need to reduce daily sedentary times by two hours The authors note their finding shows how the body adapts after weight loss blocks successful weight maintenance. Part of this effect is the reduction in energy required to move a leaner body.For example, if you walk a mile when you weight 200 pounds it takes a certain amount of energy. If you drop your weight to 150 pounds you burn fewer calories when walking a mile.Part of the adaptation is a dialing back of the bodies energy expenditure with weigh loss.The implications of their findings are that after successful weight loss, it may be necessary to increase exercise time or intensity. Alternately this study suggests two fewer hours per day on the couch in general activity may be needed.This effect is an somewhat cruel burden for the obese. Obese subjects burn about the same amount of calories daily and never-obese lean subjects.But once obese individuals lose weight, they are burning fewer calories than same-weight never-obese subjects.If you take the diet restriction effort to lose weight, this study suggest for successful weight maintenance you need to increase exercise and activity levels.Readers with more interest in this research can access the free full-text manuscript at the PMID link in the citation below.Photo of backyard cardinal is from the author's files.Follow the author on Twitter WRY999Bonomi AG, Soenen S, Goris AH, & Westerterp KR (2013). Weight-loss induced changes in physical activity and activity energy expenditure in overweight and obese subjects before and after energy restriction. PloS one, 8 (3) PMID: 23555733... Read more »

Bonomi AG, Soenen S, Goris AH, & Westerterp KR. (2013) Weight-loss induced changes in physical activity and activity energy expenditure in overweight and obese subjects before and after energy restriction. PloS one, 8(3). PMID: 23555733

January 8, 2014
10:48 AM
442 views

Vigorous Exercise and Weight Loss

by William Yates, M.D. in Brain Posts

Exercise alone without dieting appears to have a limited effect on weight loss.However, even small amounts of weight loss can lead to improved health and reduction of risk for diabetes and other obesity-related disorders.A recent study examined the effect of a supervised aerobic exercise activity on weight loss.Joseph Donnelly along with colleagues from the University of Kansas recently published their results on weight with exercise.This trial comes from the study known as the Midwest Exercise Trial-2.Ninety two subjects with a mean BMI of 31.0 (mild obesity) were randomized to one of three conditions and followed over a 10 month period.The three conditions in this controlled trial of exercise were:600 calories burned per day by exercise five times per week400 calories burned per day by exercise five times per weekNo supervised exerciseSubjects were instructed to continue their typical eating behaviors during the course of the study. The exercise was typically walking or jogging on a treadmill. The key findings from the study:Both women and men on supervised exercise lost more weight than the controls over 10 monthsWeight loss averaged 4.3% of body weight for the 400 calorie per day group and 5.7% for the 600 calorie per day groupExercise groups showed significant reductions in fat mass compared to controlMen and women in the exercise groups showed similar patterns of weight reduction and reduction in fat massThis study suggests that if your weight is 200 pounds and you begin daily exercise regimen that burns between 400 and 600 calories, you could expect a weight loss of about 10 pounds.However, results in this study point out the variability of weight loss with exercise. Some subjects lost up to 15% of body weight while other exercise subjects gained weight over the 10 month period.Since a pound of weight represents about 3500 calories this study shows the metabolic adaptation that occurs with exercise. In the 600 calorie per day group (3000 calorie per week) group one might predict more a forty pound weight loss over 10 months.But the body adapts to exercise by lower daily energy expenditure and increasing calorie intake. In the next post, I will review a recent study of the energy expenditure adaption that occurs with exercise.Readers with more interest in the current study can access the free full text manuscript by clicking on the PMID link in the citation below.Photo of a Carolina Wren is from the author's files.Follow the author on Twitter at @WRY999Donnelly JE, Honas JJ, Smith BK, Mayo MS, Gibson CA, Sullivan DK, Lee J, Herrmann SD, Lambourne K, & Washburn RA (2013). Aerobic exercise alone results in clinically significant weight loss for men and women: midwest exercise trial 2. Obesity (Silver Spring, Md.), 21 (3) PMID: 23592678... Read more »

Donnelly JE, Honas JJ, Smith BK, Mayo MS, Gibson CA, Sullivan DK, Lee J, Herrmann SD, Lambourne K, & Washburn RA. (2013) Aerobic exercise alone results in clinically significant weight loss for men and women: midwest exercise trial 2. Obesity (Silver Spring, Md.), 21(3). PMID: 23592678

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