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Rizzato A, Marcolin G, Paoli A. Non-exercise activity thermogenesis in the workplace: The office is on fire. Front Public Health 2022; 10:1024856. [PMID: 36388282 PMCID: PMC9650196 DOI: 10.3389/fpubh.2022.1024856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/05/2022] [Indexed: 01/28/2023] Open
Abstract
From the second half of the previous century, there has been a shift toward occupations largely composed of desk-based behaviors. This, inevitably, has led to a workload reduction and a consequent lower energy expenditure. On this point, small increments of the non-exercise activity thermogenesis (NEAT) could be the rationale to reach health benefits over a prolonged period. Different published researches suggest solutions to reverse sitting time and new alternative workstations have been thought to increase total physical activity. Therefore, the purpose of this narrative review is to summarize the current state of the research regarding the "NEAT approach" to weight-gain prevention in work environments. This review analyzes the main evidence regarding new alternative workstations such as standing, walking workstations, seated pedal, and gymnastic balls to replace a standard office chair.
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The active grandparent hypothesis: Physical activity and the evolution of extended human healthspans and lifespans. Proc Natl Acad Sci U S A 2021; 118:2107621118. [PMID: 34810239 DOI: 10.1073/pnas.2107621118] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The proximate mechanisms by which physical activity (PA) slows senescence and decreases morbidity and mortality have been extensively documented. However, we lack an ultimate, evolutionary explanation for why lifelong PA, particularly during middle and older age, promotes health. As the growing worldwide epidemic of physical inactivity accelerates the prevalence of noncommunicable diseases among aging populations, integrating evolutionary and biomedical perspectives can foster new insights into how and why lifelong PA helps preserve health and extend lifespans. Building on previous life-history research, we assess the evidence that humans were selected not just to live several decades after they cease reproducing but also to be moderately physically active during those postreproductive years. We next review the longstanding hypothesis that PA promotes health by allocating energy away from potentially harmful overinvestments in fat storage and reproductive tissues and propose the novel hypothesis that PA also stimulates energy allocation toward repair and maintenance processes. We hypothesize that selection in humans for lifelong PA, including during postreproductive years to provision offspring, promoted selection for both energy allocation pathways which synergistically slow senescence and reduce vulnerability to many forms of chronic diseases. As a result, extended human healthspans and lifespans are both a cause and an effect of habitual PA, helping explain why lack of lifelong PA in humans can increase disease risk and reduce longevity.
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Roemers P, Hulst Y, van Heijningen S, van Dijk G, van Heuvelen MJG, De Deyn PP, van der Zee EA. Inducing Physical Inactivity in Mice: Preventing Climbing and Reducing Cage Size Negatively Affect Physical Fitness and Body Composition. Front Behav Neurosci 2019; 13:221. [PMID: 31680890 PMCID: PMC6797814 DOI: 10.3389/fnbeh.2019.00221] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 09/06/2019] [Indexed: 01/01/2023] Open
Abstract
Physical inactivity has emerged as an important and risk factor for cardiovascular and metabolic diseases, independent of levels of exercise engagement. Moreover, inactivity is associated with poor brain functioning. However, little data on the effects of physical inactivity on the brain is available and few methods are suitable to investigate this matter. We tested whether preventing lid climbing and reducing cage size could be used to model physical inactivity in mice. Sixty young adult C57Bl6 mice (10 weeks old) were divided over six groups with different housing conditions: in cages of three different sizes with lids that either allowed or prevented lid climbing. Housing under these conditions was maintained for a period of 19 weeks before the mice were killed for body composition analysis. Physical fitness tests performed around 5 and 10 weeks into the intervention revealed that motor coordination in the balance beam test was reduced by 30.65%, grip strength by 8.91% and muscle stamina in the inverted screen test by 70.37% in non-climbing mice as compared to climbing controls. Preventing climbing increased visceral fat mass by 17.31%, but did not reduce muscle mass. Neither preventing climbing nor reducing cage size affected anxiety assessed in the Open Field test and the Elevated Plus Maze. We did not find any negative effect of inactivity on spatial learning and memory in the novel object location test or working memory measured with the Y-maze Alternation test. The reduced physical fitness and increase in visceral fat mass show that our inactivity method models most effects of physical inactivity that are observed in experimental and observational studies in humans. Whereas established methods such as hindlimb unloading mimic many of the effects of bed rest, our novel method can be applied to study the effects of less extreme forms of physical inactivity (i.e., sedentary behavior) in various disease models including rodent models for brain diseases (i.e., stroke, Alzheimer’s disease).
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Affiliation(s)
- Peter Roemers
- Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, Netherlands
| | - Yasmin Hulst
- Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, Netherlands
| | - Steffen van Heijningen
- Behavioral Neuroscience, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, Netherlands
| | - Gertjan van Dijk
- Behavioral Neuroscience, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, Netherlands
| | - Marieke J G van Heuvelen
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Peter P De Deyn
- Department of Neurology and Alzheimer Research Center, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Eddy A van der Zee
- Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, Netherlands
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Ulijaszek S. Physical activity and the human body in the (increasingly smart) built environment. Obes Rev 2018; 19 Suppl 1:84-93. [PMID: 30511510 DOI: 10.1111/obr.12790] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/13/2018] [Accepted: 09/13/2018] [Indexed: 11/29/2022]
Abstract
Physical activity in the built environment of high income countries may be changing faster than at any time prior to the 2000s, with the engagement of social media, smart devices and increasing urban smartness that has come with the Internet of Things. This article describes the most salient features of built environments that have facilitated physical activity between the 1980s and 2000s (most importantly walkability and active transport with bicycles). It goes on to use the anthropological three bodies framework in association with that of forms of capital, to explore how the use of smart devices and increasing incorporation of smartness and performativity into architecture and urban planning since the 2000s might influence physical activity. Smartness and use of smart devices in the built environment should favour increased physical activity through new types of sociality that they facilitate. In turn, engagement with such technologies offers an important opportunity for the empowerment of the individual body-self and the social body towards increased physical activity.
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Affiliation(s)
- S Ulijaszek
- Unit for Biocultural Variation and Obesity, School of Anthropology, University of Oxford, Oxford, UK
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Tapia P, Fernández-Galilea M, Robledo F, Mardones P, Galgani JE, Cortés VA. Biology and pathological implications of brown adipose tissue: promises and caveats for the control of obesity and its associated complications. Biol Rev Camb Philos Soc 2017; 93:1145-1164. [DOI: 10.1111/brv.12389] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 11/10/2017] [Accepted: 11/14/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Pablo Tapia
- Department of Nutrition, Diabetes and Metabolism, School of Medicine; Pontificia Universidad Católica de Chile, Marcoleta 367; Santiago, 8330024 Chile
| | - Marta Fernández-Galilea
- Department of Nutrition, Diabetes and Metabolism, School of Medicine; Pontificia Universidad Católica de Chile, Marcoleta 367; Santiago, 8330024 Chile
| | - Fermín Robledo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine; Pontificia Universidad Católica de Chile, Marcoleta 367; Santiago, 8330024 Chile
| | - Pablo Mardones
- Research and Innovation Office, School of Engineering; Pontificia Universidad Católica de Chile, Marcoleta 367; Santiago, 8330024 Chile
| | - José E. Galgani
- Department of Nutrition, Diabetes and Metabolism, School of Medicine; Pontificia Universidad Católica de Chile, Marcoleta 367; Santiago, 8330024 Chile
- Departamento Ciencias de la Salud; Carrera de Nutrición y Dietética, Pontificia Universidad Católica de Chile, Marcoleta 367; Santiago, 8330024 Chile
| | - Víctor A. Cortés
- Department of Nutrition, Diabetes and Metabolism, School of Medicine; Pontificia Universidad Católica de Chile, Marcoleta 367; Santiago, 8330024 Chile
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6
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Gross and relative energy cost of domestic household activities in Asian men. Eur J Clin Nutr 2016; 70:1414-1419. [PMID: 27460267 DOI: 10.1038/ejcn.2016.134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/18/2016] [Accepted: 06/24/2016] [Indexed: 02/02/2023]
Abstract
BACKGROUND/OBJECTIVES Obesity is on the rise and participation in exercise has declined. Domestic household activities may help meet the recommended daily physical activity levels. This study aimed to measure the energy costs of household activities among Asian males. SUBJECTS/METHODS This was a randomised cross-over study conducted in a whole-body calorimeter. The energy costs of 14 domestic household activities, divided into two studies, were measured in 10 healthy Asian males. Participants' weight, height, body composition and basal metabolic rate were measured on the first test visit. A standard breakfast was served and participants rested for an hour before the measurement of energy costs of domestic household activities. During the measurements, each activity was performed for 20 min, and participants rested for 30 min between activities. RESULTS The mean energy costs of domestic household activities ranged from 5.92 to 11.97 kJ/min, which were significantly different between activities (repeated measures analysis of variance, P<0.001). When expressed as metabolic equivalents (METS), all domestic household activities were classified as low-intensity physical activities. Actual METS (METSactual) were significantly different to standard METS of eight activities, which may be partly explained by the universal assumption of 3.5 ml O2/kg/min made during the calculation of METS in the Asian population. CONCLUSIONS The energy costs of a range of domestic household activities reported in this study may assist in the planning of physical activities among Asians to meet national physical activity guidelines.
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Abstract
Natural rewards, including food, water, sleep and social interactions, are required to sustain life. The neural substrates that regulate the reinforcing effects of these behaviors are also the same neurobiological mechanisms mediating mood, motivation and the rewarding effects of pharmacological stimuli. That the neuropeptide glucagon-like peptide-1 (GLP-1) is under investigation for both the homeostatic and hedonic controls of feeding is not surprising or novel. However, if the neural substrates that underline food reward are shared with other reward-related behaviors generally, then future research should investigate and embrace the likelihood that endogenous and exogenous GLP-1 receptor activation may influence multiple reward-related behaviors. Indeed, studies of the neurobiological mechanisms underlying motivated feeding behavior have informed much of the basic research investigating neural substrates of drug addiction. An emerging literature demonstrates a role for the GLP-1 system in modulating maladaptive reward behaviors, including drug and alcohol consumption. Thus, if GLP-1-based pharmacotherapies are to be used to treat drug addiction and other diseases associated with maladaptive reward behaviors (e.g. obesity and eating disorders), the neuroscience field must conduct systematic, mechanistic neuropharmacological and behavioral studies of each GLP-1 receptor-expressing nucleus within the brain. It is possible that behavioral selectivity may result from these studies, which could inform future approaches to targeting GLP-1R signaling in discrete brain nuclei to treat motivated behaviors. Equally as likely, non-selective effects on natural reward and maladaptive reward behaviors may be observed for GLP-1-based pharmacotherapies. In this case, a better understanding of the effects of increased central GLP-1R activation on motivated behaviors will aid in clinical approaches toward treating aberrant feeding behaviors and/or drug dependence.
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Affiliation(s)
- Matthew R Hayes
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine
| | - Heath D Schmidt
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania
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Scaling of free-ranging primate energetics with body mass predicts low energy expenditure in humans. Physiol Behav 2015; 138:193-9. [DOI: 10.1016/j.physbeh.2014.10.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 10/02/2014] [Accepted: 10/22/2014] [Indexed: 11/20/2022]
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Abstract
Humans and other primates are distinct among placental mammals in having exceptionally slow rates of growth, reproduction, and aging. Primates' slow life history schedules are generally thought to reflect an evolved strategy of allocating energy away from growth and reproduction and toward somatic investment, particularly to the development and maintenance of large brains. Here we examine an alternative explanation: that primates' slow life histories reflect low total energy expenditure (TEE) (kilocalories per day) relative to other placental mammals. We compared doubly labeled water measurements of TEE among 17 primate species with similar measures for other placental mammals. We found that primates use remarkably little energy each day, expending on average only 50% of the energy expected for a placental mammal of similar mass. Such large differences in TEE are not easily explained by differences in physical activity, and instead appear to reflect systemic metabolic adaptation for low energy expenditures in primates. Indeed, comparisons of wild and captive primate populations indicate similar levels of energy expenditure. Broad interspecific comparisons of growth, reproduction, and maximum life span indicate that primates' slow metabolic rates contribute to their characteristically slow life histories.
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Booth FW, Roberts CK, Laye MJ. Lack of exercise is a major cause of chronic diseases. Compr Physiol 2013; 2:1143-211. [PMID: 23798298 DOI: 10.1002/cphy.c110025] [Citation(s) in RCA: 1265] [Impact Index Per Article: 115.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chronic diseases are major killers in the modern era. Physical inactivity is a primary cause of most chronic diseases. The initial third of the article considers: activity and prevention definitions; historical evidence showing physical inactivity is detrimental to health and normal organ functional capacities; cause versus treatment; physical activity and inactivity mechanisms differ; gene-environment interaction (including aerobic training adaptations, personalized medicine, and co-twin physical activity); and specificity of adaptations to type of training. Next, physical activity/exercise is examined as primary prevention against 35 chronic conditions [accelerated biological aging/premature death, low cardiorespiratory fitness (VO2max), sarcopenia, metabolic syndrome, obesity, insulin resistance, prediabetes, type 2 diabetes, nonalcoholic fatty liver disease, coronary heart disease, peripheral artery disease, hypertension, stroke, congestive heart failure, endothelial dysfunction, arterial dyslipidemia, hemostasis, deep vein thrombosis, cognitive dysfunction, depression and anxiety, osteoporosis, osteoarthritis, balance, bone fracture/falls, rheumatoid arthritis, colon cancer, breast cancer, endometrial cancer, gestational diabetes, pre-eclampsia, polycystic ovary syndrome, erectile dysfunction, pain, diverticulitis, constipation, and gallbladder diseases]. The article ends with consideration of deterioration of risk factors in longer-term sedentary groups; clinical consequences of inactive childhood/adolescence; and public policy. In summary, the body rapidly maladapts to insufficient physical activity, and if continued, results in substantial decreases in both total and quality years of life. Taken together, conclusive evidence exists that physical inactivity is one important cause of most chronic diseases. In addition, physical activity primarily prevents, or delays, chronic diseases, implying that chronic disease need not be an inevitable outcome during life.
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Affiliation(s)
- Frank W Booth
- Departments of Biomedical Sciences, Medical Pharmacology and Physiology, and Nutrition and Exercise Physiology, Dalton Cardiovascular Institute, University of Missouri, Columbia, Missouri, USA.
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11
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Gurven M, Jaeggi AV, Kaplan H, Cummings D. Physical activity and modernization among Bolivian Amerindians. PLoS One 2013; 8:e55679. [PMID: 23383262 PMCID: PMC3561330 DOI: 10.1371/journal.pone.0055679] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/03/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Physical inactivity is a growing public health problem, and the fourth leading risk factor for global mortality. Conversely, indigenous populations living traditional lifestyles reportedly engage in vigorous daily activity that is protective against non-communicable diseases. Here we analyze physical activity patterns among the Tsimane, forager-horticulturalists of Amazonian Bolivia with minimal heart disease and diabetes. We assess age patterns of adult activity among men and women, test whether modernization affects activity levels, and examine whether nascent obesity is associated with reduced activity. METHODS AND FINDINGS A factorial method based on a large sample of behavioral observations was employed to estimate effects of age, sex, body mass index, and modernization variables on physical activity ratio (PAR), the ratio of total energy expenditure to basal metabolic rate. Accelerometry combined with heart rate monitoring was compared to the factorial method and used for nighttime sampling. Tsimane men and women display 24 hr physical activity level (PAL) of 2.02-2.15 and 1.73-1.85, respectively. Little time was spent "sedentary", whereas most activity was light to moderate, rather than vigorous. Activity peaks by the late twenties in men, and declines thereafter, but remains constant among women after the early teens. Neither BMI, fat free mass or body fat percentage are associated with PAR. There was no negative effect of modernization on physical activity. CONCLUSIONS Tsimane display relatively high PALs typical of other subsistence populations, but of moderate intensity, and not outside the range of developed populations. Despite rapidly increasing socioeconomic change, there is little evidence that total activity has yet been affected. Overweight and obesity are more prevalent among women than men, and Spanish fluency is associated with greater obesity in women. The lack of cardiovascular disease among Tsimane is unlikely caused by activity alone; further study of diet, food intake and infectious disease is needed.
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Affiliation(s)
- Michael Gurven
- Integrative Anthropological Sciences Unit, Department of Anthropology, University of California Santa Barbara, Santa Barbara, California, United States of America.
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Pontzer H, Raichlen DA, Wood BM, Mabulla AZP, Racette SB, Marlowe FW. Hunter-gatherer energetics and human obesity. PLoS One 2012; 7:e40503. [PMID: 22848382 PMCID: PMC3405064 DOI: 10.1371/journal.pone.0040503] [Citation(s) in RCA: 205] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 06/12/2012] [Indexed: 11/24/2022] Open
Abstract
Western lifestyles differ markedly from those of our hunter-gatherer ancestors, and these differences in diet and activity level are often implicated in the global obesity pandemic. However, few physiological data for hunter-gatherer populations are available to test these models of obesity. In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size. The metabolic cost of walking (kcal kg(-1) m(-1)) and resting (kcal kg(-1) s(-1)) were also similar among Hadza and Western groups. The similarity in metabolic rates across a broad range of cultures challenges current models of obesity suggesting that Western lifestyles lead to decreased energy expenditure. We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences.
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Affiliation(s)
- Herman Pontzer
- Department of Anthropology, Hunter College, New York, New York, United States of America.
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Abstract
The overall life expectancy of African American men significantly lags behind that of other major demographic groups in the United States. African American men as a group suffer extremely high rates of cancer, heart disease and many other conditions that cause substantial morbidity as well as premature and unnecessary loss of life. However, it is now widely accepted that lifestyle and environmental factors play a major role in shaping mortality and morbidity outcomes in the United States. As a result, substantial opportunities exist for improved health outcomes among African American men through intervention involving disease prevention education and lifestyle modifications aimed at promoting as well as maintaining health promoting behavioral change. This commentary examines key contributory factors to preventable morbidity and mortality among African American men as well as promising interventions for reducing existing health disparities. Such adverse factors include limited heath care access, relative underutilization of the healthcare system compared with other demographic groups, suboptimal overall levels of physical activity, poor dietary habits leading to excessive caloric intake, tobacco and alcohol use, substance use disorders (often with co-morbid infectious diseases), sexual risk behaviors, unrecognized mental health disorders driving high homicide and suicide rates, and greatly disproportionate rates of incarceration. Several intervention methodologies with potential for widespread replication are discussed. In addition, African American men’s health is presented as an integral but commonly overlooked aspect of African American community health, with wide ranging impact on African American women and children in terms of economics, relationships and overall health status.
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Affiliation(s)
- Jean J. Bonhomme
- Department of Psychiatry (JJB), Morehouse School of Medicine, East Point, Georgia
- Department of Community Health and Preventive Medicine (ADE), Morehouse School of Medicine, East Point, Georgia
| | - Aba D. Essuon
- Department of Psychiatry (JJB), Morehouse School of Medicine, East Point, Georgia
- Department of Community Health and Preventive Medicine (ADE), Morehouse School of Medicine, East Point, Georgia
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Brown JD, Naples SP, Booth FW. Effects of voluntary running on oxygen consumption, RQ, and energy expenditure during primary prevention of diet-induced obesity in C57BL/6N mice. J Appl Physiol (1985) 2012; 113:473-8. [PMID: 22653990 DOI: 10.1152/japplphysiol.00668.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Diet-induced obesity (DIO) in C57BL/6 mice is the standard model for studying obesity in mice. The few reports of DIO utilizing voluntary running provide contradictory results with respect to prevention of obesity. However, total energy expenditures associated with voluntary running during DIO are unknown. We hypothesized that voluntary running would increase the amount of total energy expended during DIO. Female C57BL/6N mice were randomly assigned to one of three experimental groups [high-fat diet with voluntary running (HFRun); high-fat diet without running (HFSed); and low-fat diet without running (LFSed)] for a 10-wk period. We confirmed production of obesity in HFSed, and more importantly demonstrated primary prevention of obesity by voluntary running in a group of cohorts (HFRun). Indirect calorimetry was performed to determine oxygen consumption (Vo(2)) and respiratory quotient (RQ). The following novel mechanisms were identified in female C57BL/6N mice: 1) HFRun showed ∼2 times greater total energy expenditures during a day compared with HFSed and LFSed; 2) HFRun had increased Vo(2) compared with HFSed and LFSed, lower RQ in the light period than HFSed, and lower RQ in both light and dark periods than LFSed; and 3) in the HFRun group, the magnitude of change in Vo(2) and RQ differed in dark and light periods during voluntary running. Our data combined with existing literature point to a potential threshold of physical activity that would prevent DIO in this mouse model. These data give a mechanistic explanation to resolve contradictory reports on whether voluntary running can prevent obesity in the DIO mouse model. In conclusion, voluntary running rescues high-fat fed, female C57BL/6N mice from obesity in DIO by doubling energy expenditure during the dark period and significantly increasing energy expenditure during the light cycle.
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Affiliation(s)
- Jacob D Brown
- Department of Medical Pharmacology, Univ. of Missouri, Columbia, MO, USA
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Cooper JA, Nguyen DD, Ruby BC, Schoeller DA. Maximal sustained levels of energy expenditure in humans during exercise. Med Sci Sports Exerc 2012; 43:2359-67. [PMID: 21606870 DOI: 10.1249/mss.0b013e31822430ed] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Migrating birds have been able to sustain an energy expenditure (EE) that is five times their basal metabolic rate. Although humans can readily reach these levels, it is not yet clear what levels can be sustained for several days. PURPOSE The study's purposes were 1) to determine the upper limits of human EE and whether or not those levels can be sustained without inducing catabolism of body tissues and 2) to determine whether initial body weight is related to the levels that can be sustained. METHODS We compiled data on documented EE as measured by doubly labeled water during high levels of physical activity (minimum of five consecutive days). We calculated the physical activity level (PAL) of each individual studied (PAL = total EE / basal metabolic rate) from the published data. Correlations were run to examine the relationship between initial body weight and body weight lost with both total EE and PAL. RESULTS The uppermost limit of EE was a peak PAL of 6.94 that was sustained for 10 consecutive days of a 95-d race. Only two studies reported PALs above 5.0; however, significant decreases in body mass were found in each study (0.45-1.39 kg·wk(-1) of weight loss). To test whether initial weight affects the ability to sustain high PALs, we found a significant positive correlation between TEE and initial body weight (r = 0.46, P < 0.05) but no correlation between PAL and body weight (r = 0.27, not statistically significant). CONCLUSIONS Some elite humans are able to sustain PALs above 5.0 for a minimum of 10 d. Although significant decreases in body weight occur at this level, catabolism of body tissue may be preventable in situations with proper energy intake. Further, initial body weight does not seem to affect the sustainability of PALs.
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Affiliation(s)
- Jamie A Cooper
- Department of Nutrition, Hospitality, and Retailing, Texas Tech University, Lubbock, TX 79409, USA.
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Sartor F, Donaldson LF, Markland DA, Loveday H, Jackson MJ, Kubis HP. Taste perception and implicit attitude toward sweet related to body mass index and soft drink supplementation. Appetite 2011; 57:237-46. [PMID: 21600942 DOI: 10.1016/j.appet.2011.05.107] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 03/23/2011] [Accepted: 05/04/2011] [Indexed: 12/16/2022]
Abstract
These studies examined the differences in sweet taste perception and implicit attitude toward sweet between normal-weight and overweight/obese adults; and tested the effects of soft drink consumption on sweet taste, explicit preference and implicit attitude toward sweet in normal-weight subjects. In study 1, normal-weight (n = 22) and overweight/obese (n = 11) adults were assessed for sweet taste intensity and pleasantness. Implicit attitude toward sweet was assessed by implicit association test (IAT). In study 2, normal-weight, lightly active adults (n = 12) underwent one month soft drink supplementation (≈760 ml/day). This increased their daily carbohydrate intake by 2.1 ± 0.2g/kg body weight. Sweet taste perception, explicit preference and implicit attitudes to sweet were assessed. In both studies salty taste was also assessed as a contrasting perception. Overweight/obese subjects perceived sweet and salty tastes as less intense (-23% and -19%, respectively) and reported higher IAT scores for sweet than normal-weight controls (2.1-fold). The supplementation changed sweet intensity/pleasantness ratings and it increased explicit preference (2.3-fold) for sweet in a subgroup of initial sucrose-dislikers. In conclusion, overweight/obese individuals are more implicitly attracted to sweet. One month of soft drink supplementation changed sweet taste perception of normal-weight subjects.
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Affiliation(s)
- Francesco Sartor
- College of Health & Behavioral Sciences, Bangor University, Bangor LL57 2PZ, UK
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Obesity and type 2 diabetes in Northern Canada's remote First Nations communities: the dietary dilemma. Int J Obes (Lond) 2011; 34 Suppl 2:S24-31. [PMID: 21151143 DOI: 10.1038/ijo.2010.236] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
First Nations populations in Northwestern Ontario have undergone profound dietary and lifestyle transformations in less than 50 years, which have contributed to the alarming rise in obesity and obesity-related diseases, in particular type 2 diabetes mellitus. Even though the genetic background of First Nations peoples differs from that of the Caucasians, genetics alone cannot explain such a high prevalence in obesity and type 2 diabetes. Modifications in lifestyle and diet are major contributors for the high prevalence of chronic diseases. What remains constant in the literature is the persistent view that locally harvested and prepared foods are of tremendous value to First Nations peoples providing important health and cultural benefits that are increasingly being undermined by western-based food habits. However, the complexities of maintaining a traditional diet require a multifaceted approach, which acknowledges the relationship between benefits, risks and viability that cannot be achieved using purely conventional medical and biological approaches. This brief review explores the biological predispositions and potential environmental factors that contribute to the development of the high incidence of obesity and obesity-related diseases in First Nations communities in Northern Canada. It also highlights some of the complexities of establishing exact physiological causes and providing effective solutions.
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Katzmarzyk PT. Physical activity, sedentary behavior, and health: paradigm paralysis or paradigm shift? Diabetes 2010; 59:2717-25. [PMID: 20980470 PMCID: PMC2963526 DOI: 10.2337/db10-0822] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 07/19/2010] [Indexed: 01/10/2023]
Affiliation(s)
- Peter T Katzmarzyk
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA.
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19
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'Putting flesh back onto the bones?' Can we predict soft tissue properties from skeletal and fossil remains? J Hum Evol 2010; 59:484-92. [PMID: 20688357 DOI: 10.1016/j.jhevol.2010.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 05/07/2010] [Accepted: 05/05/2010] [Indexed: 11/22/2022]
Abstract
Estimates of muscle and other soft tissue properties derived from hominin skeletal and fossil remains would greatly enhance descriptions of body size and shape, and prior physical and metabolic capabilities. Presently, the utility of this approach is uncertain given the complex nature of the relationship between muscle and bone. To address various principal issues, peripheral quantitative computed tomography (pQCT) imaging was used to quantify these relationships at the midshaft of the arm, forearm, and lower leg of modern human athletes (runners, field hockey players, swimmers, and cricketers) and control subjects. Given the presumed behavior patterns of prehistoric hominins, the inclusion of highly active human participants was required. Soft tissue and muscle area was compared with bone area, diaphyseal shape, and torsional rigidity. Relationships were found between muscle area and bone area in the arm, and muscle area and torsional rigidity in the forearm. However, the high standard error and prediction error that define these relationships indicate that muscle or other soft tissue predictions derived from hominin fossil or skeletal remains would be untenable. In the tibia, the relationship between soft tissue properties and bone properties were primarily explained by covariation with body size. While the strength of the muscle-bone relationships in the arm and forearm vary among athletes and control subgroups, it appears that habitual upper limb loading performed throughout adolescence neither strengthens nor weakens this relationship. Future attempts to estimate soft tissue properties from osseous tissue may be improved through the use of medical CT or MRI to image complete limb segments and isolate individual muscles.
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Abstract
The assigned title for the Lindhard presentation was to examine the future of genes, physical activity and health. The current review is a summary of this presentation. Caution is expressed that technology is improving so rapidly that a future view is limited to a few years as opposed to the 100 years passing since Lindhard's achievements. The near futuristic opportunities and challenges for four major topic topics are reviewed here. Concerns are expressed over current usage of the terms 'control' group and 'non-responders' in exercise research. Our view is that 'control' needs to be differentiated between its usage for treatments of exercise to restore natural functions in individuals with less than healthy levels of physical activity and the inherited genome's expectation for physical activity levels to maintain normal function. For the second discussed topic, it is proposed that the term 'non-responders' should be replaced by the term 'low sensitivity' as there may be no such human who is a non-responder to every exercise adaptation. The third futuristic topic is exercise prescription as envisioned for individualized medicine. However, numerous limitations and challenges exist to truly optimal exercise medicine at the level of one individual. Finally, preventative physical activity medicine is discussed. Physical activity as a therapy now exists to prevent most of the chronic diseases. The future needs to understand the molecular basis for how the body becomes dysfunctional when its level of physical activity does not match the norm of physical activity that selected our inherited genome.
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Affiliation(s)
- F W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA.
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Kozak LP, Newman S, Chao PM, Mendoza T, Koza RA. The early nutritional environment of mice determines the capacity for adipose tissue expansion by modulating genes of caveolae structure. PLoS One 2010; 5:e11015. [PMID: 20574519 PMCID: PMC2888576 DOI: 10.1371/journal.pone.0011015] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 05/14/2010] [Indexed: 01/11/2023] Open
Abstract
While the phenomenon linking the early nutritional environment to disease susceptibility exists in many mammalian species, the underlying mechanisms are unknown. We hypothesized that nutritional programming is a variable quantitative state of gene expression, fixed by the state of energy balance in the neonate, that waxes and wanes in the adult animal in response to changes in energy balance. We tested this hypothesis with an experiment, based upon global gene expression, to identify networks of genes in which expression patterns in inguinal fat of mice have been altered by the nutritional environment during early post-natal development. The effects of over- and under-nutrition on adiposity and gene expression phenotypes were assessed at 5, 10, 21 days of age and in adult C57Bl/6J mice fed chow followed by high fat diet for 8 weeks. Under-nutrition severely suppressed plasma insulin and leptin during lactation and diet-induced obesity in adult mice, whereas over-nourished mice were phenotypically indistinguishable from those on a control diet. Food intake was not affected by under- or over-nutrition. Microarray gene expression data revealed a major class of genes encoding proteins of the caveolae and cytoskeleton, including Cav1, Cav2, Ptrf (Cavin1), Ldlr, Vldlr and Mest, that were highly associated with adipose tissue expansion in 10 day-old mice during the dynamic phase of inguinal fat development and in adult animals exposed to an obesogenic environment. In conclusion gene expression profiles, fat mass and adipocyte size in 10 day old mice predicted similar phenotypes in adult mice with variable diet-induced obesity. These results are supported by phenotypes of KO mice and suggest that when an animal enters a state of positive energy balance adipose tissue expansion is initiated by coordinate changes in mRNA levels for proteins required for modulating the structure of the caveolae to maximize the capacity of the adipocyte for lipid storage.
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Affiliation(s)
- Leslie P Kozak
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA.
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Kozak LP. Brown fat and the myth of diet-induced thermogenesis. Cell Metab 2010; 11:263-7. [PMID: 20374958 PMCID: PMC2867325 DOI: 10.1016/j.cmet.2010.03.009] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 03/15/2010] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
The notion that brown adipose tissue (BAT) in mice or humans maintains energy balance by burning off excess calories seems incompatible with evolutionary biology. Studies in obese rats and mice lacking UCP1 indicate that diet-induced thermogenesis by BAT is unlikely.
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Affiliation(s)
- Leslie P Kozak
- Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
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Simmen B, Bayart F, Rasamimanana H, Zahariev A, Blanc S, Pasquet P. Total energy expenditure and body composition in two free-living sympatric lemurs. PLoS One 2010; 5:e9860. [PMID: 20360848 PMCID: PMC2845615 DOI: 10.1371/journal.pone.0009860] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 02/28/2010] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Evolutionary theories that account for the unusual socio-ecological traits and life history features of group-living prosimians, compared with other primates, predict behavioral and physiological mechanisms to conserve energy. Low energy output and possible fattening mechanisms are expected, as either an adaptive response to drastic seasonal fluctuations of food supplies in Madagascar, or persisting traits from previously nocturnal hypometabolic ancestors. Free ranging ring-tailed lemurs (Lemur catta) and brown lemurs (Eulemur sp.) of southern Madagascar have different socio-ecological characteristics which allow a test of these theories: Both gregarious primates have a phytophagous diet but different circadian activity rhythms, degree of arboreality, social systems, and slightly different body size. METHODOLOGY AND RESULTS Daily total energy expenditure and body composition were measured in the field with the doubly labeled water procedure. High body fat content was observed at the end of the rainy season, which supports the notion that individuals need to attain a sufficient physical condition prior to the long dry season. However, ring-tailed lemurs exhibited lower water flux rates and energy expenditure than brown lemurs after controlling for body mass differences. The difference was interpreted to reflect higher efficiency for coping with seasonally low quality foods and water scarcity. Daily energy expenditure of both species was much less than the field metabolic rates predicted by various scaling relationships found across mammals. DISCUSSION We argue that low energy output in these species is mainly accounted for by low basal metabolic rate and reflects adaptation to harsh, unpredictable environments. The absence of observed sex differences in body weight, fat content, and daily energy expenditure converge with earlier investigations of physical activity levels in ring-tailed lemurs to suggest the absence of a relationship between energy constraints and the evolution of female dominance over males among lemurs. Nevertheless, additional seasonal data are required to provide a definitive conclusion.
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Affiliation(s)
- Bruno Simmen
- UMR 7206, Eco-anthropologie et Ethnobiologie, Centre National de la Recherche Scientifique and Muséum National d'Histoire Naturelle, Brunoy, France.
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Butler AA, Kozak LP. A recurring problem with the analysis of energy expenditure in genetic models expressing lean and obese phenotypes. Diabetes 2010; 59:323-9. [PMID: 20103710 PMCID: PMC2809965 DOI: 10.2337/db09-1471] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Andrew A. Butler
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida
| | - Leslie P. Kozak
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
- Corresponding author: Leslie Kozak,
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Grill HJ. Leptin and the systems neuroscience of meal size control. Front Neuroendocrinol 2010; 31:61-78. [PMID: 19836413 PMCID: PMC2813996 DOI: 10.1016/j.yfrne.2009.10.005] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 10/12/2009] [Accepted: 10/13/2009] [Indexed: 12/14/2022]
Abstract
The development of effective pharmacotherapy for obesity will benefit from a more complete understanding of the neural pathways and the neurochemical signals whose actions result in the reduction of the size of meals. This review examines the neural control of meal size and the integration of two principal sources of that control--satiation signals arising from the gastrointestinal tract and CNS leptin signaling. Four types of integrations that are central to the control of meal size are described and each involves the neurons of the nucleus tractus solitarius (NTS) in the dorsal hindbrain. Data discussed show that NTS neurons integrate information arising from: (1) ascending GI-derived vagal afferent projections, (2) descending neuropeptidergic projections from leptin-activated arcuate and paraventricular nucleus neurons, (3) leptin signaling in NTS neurons themselves and (4) melanocortinergic projections from NTS and hypothalamic POMC neurons to NTS neurons and melanocortinergic modulation of vagal afferent nerve terminals that are presynaptic to NTS neurons.
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Affiliation(s)
- Harvey J Grill
- Graduate Groups of Psychology and Neuroscience, University of Pennsylvania, 3720 Walnut Street, Philadelphia, PA 19104, USA
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26
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Booth FW, Laye MJ. Lack of adequate appreciation of physical exercise's complexities can pre-empt appropriate design and interpretation in scientific discovery. J Physiol 2009; 587:5527-39. [PMID: 19723782 PMCID: PMC2805365 DOI: 10.1113/jphysiol.2009.179507] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Accepted: 09/01/2009] [Indexed: 12/19/2022] Open
Abstract
Two major issues are presented. First, a challenge is made by us that a misunderstanding of physiology has led to incomplete or wrong functional designations of genes in some cases. Normal physiological processes are dynamic, integrated and periodic, and, therefore, it is difficult to define normal physiological function by looking at a single time point or single process in a non-stressed subject. The ability of the organism to successfully respond to homeostatic disruptions defines normal physiology. Genes were selected for survival and to appropriately respond to stresses, such as physical activity. Omitting gene functions by restricting them to non-stressful conditions could lead to less than optimal primary preventions, treatments and cures for diseases. Physical exercise, as a stressor, should be used to better demonstrate the complete functional classifications of some genes. Second, the challenge from others of an 'exercise pill' as a mimetic of natural physical activity will be shown to be lacking a scientific basis. The concept of an 'exercise pill'/'exercise mimetic' demonstrates an inadequate appreciation of the complexities in integrating cell, tissue, organ and systems during both acute disruptions in homeostasis by a single bout of exercise, and longer-term chronic adaptations to different types of exercise such as resistance and endurance. It is our opinion that those promoting drugs targeting a single or few molecules should not redefine the term 'exercise' and exercise concepts in an attempt to sensationalize findings. Additionally, the scientific criteria that the authors demand to be met to legitimately use the terms 'exercise pill' and 'exercise mimetic' are presented.
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Affiliation(s)
- F W Booth
- Veterinary Medicine Bldg E102, University of Missouri, Columbia, MO 65211, USA.
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27
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Nedeltcheva AV, Kilkus JM, Imperial J, Kasza K, Schoeller DA, Penev PD. Sleep curtailment is accompanied by increased intake of calories from snacks. Am J Clin Nutr 2009; 89:126-33. [PMID: 19056602 PMCID: PMC2615460 DOI: 10.3945/ajcn.2008.26574] [Citation(s) in RCA: 502] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Short sleep is associated with obesity and may alter the endocrine regulation of hunger and appetite. OBJECTIVE We tested the hypothesis that the curtailment of human sleep could promote excessive energy intake. DESIGN Eleven healthy volunteers [5 women, 6 men; mean +/- SD age: 39 +/- 5 y; mean +/- SD body mass index (in kg/m(2)): 26.5 +/- 1.5] completed in random order two 14-d stays in a sleep laboratory with ad libitum access to palatable food and 5.5-h or 8.5-h bedtimes. The primary endpoints were calories from meals and snacks consumed during each bedtime condition. Additional measures included total energy expenditure and 24-h profiles of serum leptin and ghrelin. RESULTS Sleep was reduced by 122 +/- 25 min per night during the 5.5-h bedtime condition. Although meal intake remained similar (P = 0.51), sleep restriction was accompanied by increased consumption of calories from snacks (1087 +/- 541 compared with 866 +/- 365 kcal/d; P = 0.026), with higher carbohydrate content (65% compared with 61%; P = 0.04), particularly during the period from 1900 to 0700. These changes were not associated with a significant increase in energy expenditure (2526 +/- 537 and 2390 +/- 369 kcal/d during the 5.5-h and 8.5-h bedtime periods, respectively; P = 0.58), and we found no significant differences in serum leptin and ghrelin between the 2 sleep conditions. CONCLUSIONS Recurrent bedtime restriction can modify the amount, composition, and distribution of human food intake, and sleeping short hours in an obesity-promoting environment may facilitate the excessive consumption of energy from snacks but not meals.
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Malina RM, Little BB. Physical activity: the present in the context of the past. Am J Hum Biol 2008; 20:373-91. [PMID: 18433002 DOI: 10.1002/ajhb.20772] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In the broad sense, modern humans have lived in an environment in which physical activity and associated movement skills were central, especially in the context of physical competition with other animals. The physically active lifestyle of earlier human populations has been emphasized, especially the cardiovascular endurance component and energy expenditure, but less attention has been devoted to the gross and fine motor skills that are essential components of this lifestyle. Motor skills developed through practice are important determinants of success and survival in preindustrial societies. In industrial and postindustrial societies, on the other hand, the role of physical activity is different, with prowess in certain areas of physical expertise (e.g., accuracy with projectiles, muscular strength, among others) and prolonged exertion (i.e., cardiovascular endurance) less important for survival. The combined effects of the transition to a sedentary lifestyle and attendant dietary changes have resulted first an epidemic of coronary heart disease and more recently an epidemic of overweight/obesity in postindustrial societies. Although mortality associated with coronary heart disease has declined, due largely to biomedical advances, overweight and obesity have increased concomitantly with population reduction in physical activity (energy expenditure) and increased calorie (energy) consumption. The current scenario begs several questions which have implications for contemporary human biology related to sustaining the pace of cultural change on a biological base that is increasingly being compromised by physical inactivity, overweight, and obesity.
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Affiliation(s)
- Robert M Malina
- Department of Kinesiology and Health Education, University of Texas at Austin and Research Professor, Tarleton State University, Stephenville, Texas, USA.
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Jarosz PA, Fata E, Bowen SE, Jen KLC, Coscina DV. Effects of abuse pattern of gestational toluene exposure on metabolism, feeding and body composition. Physiol Behav 2007; 93:984-93. [PMID: 18272189 DOI: 10.1016/j.physbeh.2007.12.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 11/13/2007] [Accepted: 12/19/2007] [Indexed: 11/20/2022]
Abstract
AIMS Inhalant abuse during pregnancy lowers birth weight and impedes early development. These studies explored the effects of brief, repeated, prenatal toluene exposures in pregnant female rats on body weight, metabolic rate, body composition, and food intake in their offspring. METHOD Rats were exposed to 0, 8000, 12,000, or 16,000 ppm of toluene twice daily for 15 min from gestational days 8 to 20. The effects of such exposures on post-weaning litter weights, oxygen consumption, carbon dioxide output, and body fat content were determined in 2 cohorts (n=23, n=24) of offspring. Food intakes and weight changes in response to 3 different diets (regular chow, purified diet, purified high fat diet) were examined in another cohort (n=24) from postnatal days 72 to 116. RESULTS Litter weights showed a significant linear decrease as a function of toluene dose. Offspring exposed to the 16,000 ppm toluene dose displayed statistically lower energy expenditures than control rats. Male rats exposed to 8000 or 16,000 ppm toluene had significantly greater percentage of body fat as well as total body fat than the other groups. Toluene also significantly suppressed weight gain over the time chow was consumed compared to the 0 ppm control group. Finally there were trends for a main effect of toluene dose on food intake during chow and during high fat diet consumption, with rats in the 12,000 ppm group consuming more than the 0 ppm group on both diets. DISCUSSION These data suggest that, in addition to other previously documented abnormalities in neurological development and behavior, the physiological regulation of metabolism and body composition in males as well as food intake and weight gain in both sexes may be altered by prenatal exposure to toluene.
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Abstract
Obesity occurs when energy intake exceeds energy expenditure over a protracted period of time. The energy expenditure associated with everyday activity is called NEAT (Nonexercise activity thermogenesis). NEAT varies between two people of similar size by 2000 kcal day(-1) because of people's different occupations and leisure-time activities. Data support the central hypothesis that NEAT is pivotal in the regulation of human energy expenditure and body weight regulation and that NEAT is important for understanding the cause and effective treatment for obesity.
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Affiliation(s)
- J A Levine
- Endocrine Research Unit, Mayo Clinic, Rochester, MN 5590, USA.
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31
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Young GS, Kirkland JB. Rat models of caloric intake and activity: relationships to animal physiology and human health. Appl Physiol Nutr Metab 2007; 32:161-76. [PMID: 17486157 DOI: 10.1139/h06-082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Every rodent experiment is based on important parameters concerning the levels of caloric intake and physical activity. In many cases, these decisions are not made consciously, but are based on traditional models. For experimental models directed at the study of caloric intake and activity, the selection of parameters is usually aimed at modeling human conditions, the ultimate goal of which is to gain insight into the pathophysiology of the disease process in man. In each model, it is important to understand the influence of diet, exercise, and genetic background on physiology and the development of disease states. Along the continuum of energy intake from caloric restriction to high-fat feeding, and of energy output from total inactivity to forced exercise, a number of models are used to study different disease states. In this paper, we will evaluate the influence of the quantity and composition of diet and exercise in several animal models, and will discuss how each model can be applied to various human conditions. This review will be limited to traditional models using the rat as the experimental animal, and although it is not an exhaustive list, the models presented are those most commonly represented in the literature. We will also review the mechanisms by which each affects rat physiology, and will compare these to the analogous mechanisms in the modeled human disease state. We hope that the information presented here will help researchers make choices among the available models and will encourage discussion on the interpretation and extrapolation of results obtained from traditional and novel rodent experiments on diet, exercise, and chronic disease.
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Affiliation(s)
- Genevieve S Young
- Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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Affiliation(s)
- K R Fox
- Department of Exercise, Nutrition and Health Sciences, University of Bristol, Bristol, UK.
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33
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Affiliation(s)
- S J Ulijaszek
- Institute of Social and Cultural Anthropology, University of Oxford, Oxford, UK.
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Doucet E. Eat, run, and…shiver? From the exercise – diet and energy balance symposium at CSEP 2005. Appl Physiol Nutr Metab 2007; 32:503-4. [PMID: 17510689 DOI: 10.1139/h07-016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This short introduction includes a brief description of papers that were prepared following the “Symposium on Exercise – Diet and Energy Balance”, which was presented at the Canadian Society for Exercise Physiology annual meeting in the autumn of 2005. Briefly, these three papers discuss findings related to (i) the emerging role of exercise in the treatment of obesity and its co-morbidities, (ii) the role of novel proteins secreted by fat, and (iii) the control of appetite and food intake after successful weight loss.
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Affiliation(s)
- Eric Doucet
- Behavioural and Metabolic Research Unit, School of Human Kinetics, University of Ottawa, Ontario, Canada.
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Heymsfield SB, Harp JB, Rowell PN, Nguyen AM, Pietrobelli A. How much may I eat? Calorie estimates based upon energy expenditure prediction equations. Obes Rev 2006; 7:361-70. [PMID: 17038130 DOI: 10.1111/j.1467-789x.2006.00249.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
How much may I eat? Most healthcare workers, when asked this question, have insufficient knowledge to educate their patients on a healthy energy intake level. In this review we examine the available methods for estimating adult energy requirements with a focus on the newly developed National Academy of Sciences/Institute of Medicine (NAS/IOM) doubly-labelled water total energy expenditure (TEE) prediction equations. An overview is first provided of the traditional factorial method of estimating energy requirements. We then extend this overview by exploring the development of the NAS/IOM TEE prediction models and their role in estimating energy requirements as a function of sex, age, weight, height and physical activity level. The NAS/IOM prediction models were developed for evaluating group energy requirements, although the formulas can be applied in individual 'example' patients for educational purposes. Potential limitations and interpretation issues of both the factorial and NAS/IOM methods are examined. This information should provide healthcare professionals with the tools and understanding to appropriately answer the question, 'How much may I eat?'
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Affiliation(s)
- S B Heymsfield
- Merck & Company, Metabolism and Epidemiology, Rahway, New Jersey 07065-0900, USA.
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Levine JA, Vander Weg MW, Hill JO, Klesges RC. Non-exercise activity thermogenesis: the crouching tiger hidden dragon of societal weight gain. Arterioscler Thromb Vasc Biol 2006; 26:729-36. [PMID: 16439708 DOI: 10.1161/01.atv.0000205848.83210.73] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Non-exercise activity thermogenesis (NEAT) is the energy expenditure of all physical activities other than volitional sporting-like exercise. NEAT includes all the activities that render us vibrant, unique, and independent beings such as working, playing, and dancing. Because people of the same weight have markedly variable activity levels, it is not surprising that NEAT varies substantially between people by up to 2000 kcal per day. Evidence suggests that low NEAT may occur in obesity but in a very specific fashion. Obese individuals appear to exhibit an innate tendency to be seated for 2.5 hours per day more than sedentary lean counterparts. If obese individuals were to adopt the lean "NEAT-o-type," they could potentially expend an additional 350 kcal per day. Obesity was rare a century ago and the human genotype has not changed over that time. Thus, the obesity epidemic may reflect the emergence of a chair-enticing environment to which those with an innate tendency to sit, did so, and became obese. To reverse obesity, we need to develop individual strategies to promote standing and ambulating time by 2.5 hours per day and also re-engineer our work, school, and home environments to render active living the option of choice.
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Affiliation(s)
- James A Levine
- Endocrine Research Unit, Mayo Clinic, Rochester, MN 55905, USA.
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37
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Affiliation(s)
- Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
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