Non-exercise activity thermogenesis: the crouching tiger hidden dragon of societal weight gain

Effect of Active Workstations on Neurocognitive Performance and Typing Skills: A Randomized Clinical Trial

BACKGROUND

Extended sedentary behavior is a risk factor for chronic disease and mortality, even among those who exercise regularly. Given the time constraints of incorporating physical activity into daily schedules, and the high likelihood of sitting during office work, this environment may serve as a potentially feasible setting for interventions to reduce sedentary behavior.

METHODS AND RESULTS

A randomized cross-over clinical trial was conducted at an employee wellness center. Four office settings were evaluated on 4 consecutive days: stationary or sitting station on day 1 (referent), and 3 subsequent active workstations (standing, walking, or stepper) in randomized order. Neurocognitive function (Selective Attention, Grammatical Reasoning, Odd One Out, Object Reasoning, Visuospatial Intelligence, Limited-Hold Memory, Paired Associates Learning, and Digit Span) and fine motor skills (typing speed and accuracy) were tested using validated tools. Average scores were compared among stations using linear regression with generalized estimating equations to adjust standard errors. Bonferroni method adjusted for multiple comparisons. Healthy subjects were enrolled (n=44), 28 (64%) women, mean±SD age 35±11 years, weight 75.5±17.1 kg, height 168.5±10.0 cm, and body mass index 26.5±5.2 kg/m2. When comparing active stations to sitting, neurocognitive test either improved or remained unchanged, while typing speed decreased without affecting typing errors. Overall results improved after day 1, suggesting habituation. We observed no major differences across active stations, except decrease in average typing speed 42.5 versus 39.7 words per minute with standing versus stepping (P=0.003).

CONCLUSIONS

Active workstations improved cognitive performance, suggesting that these workstations can help decrease sedentary time without work performance impairment.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT06240286.

Walking net V ˙ O2 rises with advancing age in older women: where to go from here?

PURPOSE

Walking net V ˙ O2 tends to increase with advancing age; however, factors contributing to this relationship have not been widely described. The implications of such findings could inform targeted strategies to promote independent mobility in older adults. Herein, we evaluated the relationship between net V ˙ O2 and age at two submaximal workloads while exploring potential moderators of this relationship.

METHODS

Secondary analyses were performed on 35 older (65 ± 3 years) women who completed a battery of physical assessments including fixed-speed, non-graded and graded (+ 2.5%) treadmill walking with indirect calorimetry to determine net V ˙ O2. Maximal oxygen uptake ( V ˙ O2max), knee extensor maximal isometric voluntary contraction (MVC), peak rate of torque development (RTD), and plantar flexor range-of-motion (PFROM) were also measured.

RESULTS

Bivariate correlations showed non-graded (r = 0.403, p = 0.017) and graded (r = 0.413, p = 0.014) net V ˙ O2 were positively related to age. Notably, these relationships strengthened after adjusting for V ˙ O2max. Regression modeling showed age, RTD:MVC ratio (composite of muscle performance), and PFROM together explained 49% and 34% of the variance in non-graded and graded net V ˙ O2, respectively. Further analyses suggested knee extensor MVC moderates the relationship between non-graded net V ˙ O2 and age, accounting for 9% of the variance [ΔR2 = 0.090, F (1,31) = 4.13, p = 0.05].

CONCLUSION

These data support the premise that, in older women, walking net V ˙ O2 rises with advancing age, and additionally, the RTD:MVC ratio and PFROM are independent correlates of non-graded net V ˙ O2. Exercise interventions with a high degree of training specificity including explosive, velocity-based elements may promote independent mobility in older women.

Analysis of Walking Economy after Sleeve Gastrectomy in Patients with Severe Obesity

BACKGROUND

Obesity is associated with a higher energy cost of walking which affects activities of daily living. Bariatric surgery with sleeve gastrectomy (SG) has beneficial effects on weight loss and comorbidities.

PURPOSE

The aim of this study was to analyze the impact of SG on walking economy in subjects with severe obesity.

METHODS

This observational cohort study included all patients with morbid obesity who were considered suitable candidates for SG between June 2017 and June 2019. Each patient underwent an incremental cardiopulmonary exercise test on a treadmill (modified Bruce protocol) one month before and six months after SG. Data on the energy cost of walking were recorded during three protocol stages (stage 0-slow flat walking: speed 2.7 km/h, slope 0%; stage ½-slow uphill walking: speed 2.7 km/h, slope 5%; stage 1-fast uphill walking: speed 4.0 km/h, slope 8%).

RESULTS

139 patients with morbid obesity (78% women; age 44.1 ± 10.7 years; BMI 42.5 ± 4.7 kg/m²) were included in the study. At six months post-SG, patients presented with a significantly decreased body weight (-30.5 ± 17.2 kg; p < 0.05), leading to an average BMI of 31.6 ± 4.2 kg/m². The net energy cost of walking (measured in J/m and J/kg/m) of the subjects was lower compared to pre-SG at all three protocol stages. This improvement was also confirmed when the subjects were grouped by gender and obesity classes.

CONCLUSION

After a significant weight loss induced by SG, regardless of the severity of obesity and gender, patients exhibited a lower energy expenditure and an improved walking economy. These changes make it easier to perform daily routines and may facilitate an increase in physical activity.

Compensatory mechanisms from different exercise intensities in type 2 diabetes: a secondary analysis of a 1-year randomized controlled trial

AIMS

This investigation aimed to determine the effect of different intensities of training on non-exercise physical activity (NEPA) and estimated thermogenesis (NEAT) from a 1-year exercise randomized controlled trial (RCT) in individuals with type 2 diabetes mellitus (T2DM) on non-training days. Additionally, changes in NEPA and estimated NEAT in those who failed (low-responders) or succeeded (high-responders) in attaining exercise-derived clinically meaningful reductions in body weight (BW) and fat mass (FM) (i.e., 6% for FM and 3% for BW) was assessed.

METHODS

Individuals with T2DM (n = 80) were enrolled in a RCT with three groups: resistance training combined with moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) and a control group. Of the 80 participants, 56 (completed data) were considered for this secondary analysis. NEPA and estimated NEAT were obtained by accelerometry and body composition through dual-energy X-ray absorptiometry.

RESULTS

After adjustments, no time*group interactions were found for estimated NEAT in the MICT (β = - 5.33, p = 0.366) and HIIT (β = - 5.70, p = 0.283), as well as for NEPA in the MICT (β = - 452.83, p = 0.833) and HIIT (β = - 2770.76, p = 0.201), when compared to controls. No compensatory changes in NEPA and estimated NEAT were observed when considering both low-responders and high-responders to FM and BW when compared to controls.

CONCLUSIONS

Both MICT and HIIT did not result in any compensatory changes in estimated NEAT and NEPA with the intervention on non-training days. Moreover, no changes in estimated NEAT and NEPA were found when categorizing our participants as low-responders and high-responders to FM and BW when compared to controls. Trial registration clinicaltrials.gov ID. NCT03144505.

Insights into Non-Exercise Physical Activity on Control of Body Mass: A Review with Practical Recommendations

Non-exercise physical activity (NEPA), also called unstructured or informal physical activity, refers to those daily activities that require movement of the human body without planning or strict control of the physical effort made. Due to new technologies and motorized transportation devices, the general population has significantly decreased its NEPA. This increase in sedentary lifestyles, physical inactivity, and excessive energy intake is considered a risk factor for obesity, non-communicable diseases (NCDs), and all-cause mortality. Searching in PubMed/MEDLINE and Web of Science databases, a narrative review of NEPA was carried out to address its conceptualization, promotion strategies for the general population, and monitoring through wearable devices. It is strongly recommended that governmental entities, health practitioners, and the construction industry adhere to "The Global Action Plan on Physical Activity 2018-2030: More Active People for a Healthier World" and implement different salutogenic urban strategies. These strategies aim to generate environments that motivate increases in NEPA, such as cycling and walking transportation (between 5000-12,500 steps per day), and the progression to physical exercise. There is a wide variety of electronic devices for personal use, such as accelerometers, smartphone apps, or "smart clothes", that allow for the monitoring of NEPA, some with a wide range of analysis variables contributing to the estimation of total daily energy expenditure and the promotion of healthy habits. In general, the further promotion and monitoring of NEPA is required as part of a strategy to promote healthy habits sustainable over time for the prevention and control of obesity and NCDs.

Dose-dependent associations of joint aerobic and muscle-strengthening exercise with obesity: A cross-sectional study of 280,605 adults

BACKGROUND

Emerging epidemiological evidence suggests that compared to engaging in 1 activity mode alone, a combination of moderate-to-vigorous physical activity (MVPA: brisk walking/jogging, cycling) and muscle-strengthening exercise (MSE: push-ups/sit-ups, using weight machines) has more favorable associations with optimal weight status. However, few studies have examined the dose-dependent and joint associations of MVPA and MSE with obesity.

METHODS

Based on cross-sectional analyses of the European Health Interview Survey Wave 2 (2013-2014), we examined prevalence ratios (PRs) of joint and stratified associations between MVPA (4 categories: (i) 0 min/week, (ii) 1-149 min/week, (iii) 150-299 min/week, and (iv) ≥300 min/week) and MSE (3 categories: (i) 0 day/week, (ii) 1 day/week, and (iii) ≥2 days/week) with body mass index-defined obesity (body mass index of ≥30.0 kg/m²) using Poisson regression with robust error variance. PRs were examined unadjusted and adjusted for sociodemographic and lifestyle characteristics (e.g., sex, age, education, income, and smoking status).

RESULTS

Data were available for 280,456 adults (≥18 years), of which 46,166 (15.5%) were obese. The interaction MVPA × MSE guideline adherence was statistically significant for obesity (p ≤ 0.05). The joint MVPA-MSE analysis showed that compared to the reference group (i.e., no MVPA and no MSE), the PRs followed a dose-dependent pattern, with the lowest observed among those reporting ≥150 MVPA min/week and ≥1 MSE days/week (PR: 0.43; 95% confidence interval: 0.41-0.46). When stratified across each MVPA strata, the PRs were mostly lower among those engaging in MSE 1 day/week, as compared to those doing MSE ≥2 days/week.

CONCLUSION

There was evidence for a dose-dependent association between joint MVPA-MSE with a reduced prevalence of obesity. Public health strategies for the prevention and management of obesity should recommend both MVPA and MSE.

Relative leg press strength relates to activity energy expenditure in older women: Implications for exercise prescription

Limited work has evaluated how leg press strength (LPS), relative to body mass (i.e., rLPS), affects heart rate (HR) responses during activities of daily living. Such information would prove useful by informing a specific level of rLPS needed to promote independent mobility and physical activity. Secondary analyses were performed on baseline measures of 76 untrained older (65 ± 4 y) women. After familiarization, one-repetition maximum leg press was converted to rLPS by dividing the external load lifted (kg) by body mass (BM). Participants were stratified according to percentile of age-group norms of rLPS: ≤50 % (low, ≤0.99 kg/BM, n = 15), 51-89 % (middle, 1.0-1.31 kg/BM, n = 31), and ≥90 % (high, ≥1.32 kg/BM, n = 30). HR was measured at rest and during laboratory-based tasks including fixed-speed (0.89 m·s^-1) non-graded treadmill walking, graded (2.5 %) treadmill walking, and stair stepping. Maximal oxygen uptake (V̇O_2max) was measured via indirect calorimetry. Doubly labeled water was used to quantify activity energy expenditure (AEE) over a 14-d period. Relative LPS per group were: 0.85 ± 0.12 (low), 1.16 ± 0.09 (middle), and 1.55 ± 0.25 (high) (p < 0.001). Significant between-group differences in HR emerged during both walking tasks and stair stepping - with the high rLPS group having the lowest HR. AEE between-group comparisons did not yield statistical significance (p = 0.084), however, rLPS correlated with AEE (r = 0.234, p = 0.042) and V̇O_2max (r = 0.430, p < 0.001). Such findings suggest a higher rLPS attenuates HR for weight-bearing activities while also demonstrating a significant, albeit modest, positive link to AEE among older women. This information may be especially relevant for informing thresholds of rLPS linked to mobility and functional independence in older women.

Identification of the Exercise and Time Effects on Human Skeletal Muscle through Bioinformatics Methods

Background

The human body has more than 600 kinds of skeletal muscles, which accounts for about 40% of the whole weight. Most skeletal muscles can make bones move, and their strength and endurance directly affect their performance during exercise.

Methods

To determine the effects of exercise and time on human skeletal muscle, we downloaded the microarray expression profile of GSE1832 and analyzed it to select differentially expressed genes (DEGs). Then, a protein-protein interaction (PPI) network was established, and the hub genes were identified. Afterwards, DEGs were applied to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Finally, with the help of Gene Set Enrichment Analysis (GSEA), the gene sets in the 7 samples were enriched in the KEGG pathway.

Results

Through a series of bioinformatics analyses, we obtained a total of 271 DEGs. After that, four hub genes were determined through the PPI network, namely, EP300, STAT1, CDKN1A, and RAC2. In addition, we got that these DEGs were enriched in GO, such as regulation of cell population proliferation, cellular water homeostasis, and so on, and in KEGG, namely, hepatitis B, Epstein–Barr virus infection, small cell lung cancer, pathways in cancer, and others. Finally, the gene set in the samples obtained by GSEA was enriched in the cell cycle, chemokine signaling pathway, DNA replication, cytokine receptor interaction, ECM receptor interaction, and focal adhesion in KEGG.

Conclusion

The findings obtained in this study will provide new clues for elucidating the mechanism of exercise and time on human skeletal muscles.

Ten things to know about ten cardiovascular disease risk factors - 2022

The American Society for Preventive Cardiology (ASPC) "Ten things to know about ten cardiovascular disease risk factors - 2022" is a summary document regarding cardiovascular disease (CVD) risk factors. This 2022 update provides summary tables of ten things to know about 10 CVD risk factors and builds upon the foundation of prior annual versions of "Ten things to know about ten cardiovascular disease risk factors" published since 2020. This 2022 version provides the perspective of ASPC members and includes updated sentinel references (i.e., applicable guidelines and select reviews) for each CVD risk factor section. The ten CVD risk factors include unhealthful dietary intake, physical inactivity, dyslipidemia, pre-diabetes/diabetes, high blood pressure, obesity, considerations of select populations (older age, race/ethnicity, and sex differences), thrombosis (with smoking as a potential contributor to thrombosis), kidney dysfunction and genetics/familial hypercholesterolemia. Other CVD risk factors may be relevant, beyond the CVD risk factors discussed here. However, it is the intent of the ASPC "Ten things to know about ten cardiovascular disease risk factors - 2022" to provide a tabular overview of things to know about ten of the most common CVD risk factors applicable to preventive cardiology and provide ready access to applicable guidelines and sentinel reviews.

Association between Sedentary Time and 6-Year All-Cause Mortality in Adults: The Rural Chinese Cohort Study

OBJECTIVES

This study aims to prospectively explore the association between sedentary time and the risk of all-cause mortality in adults based on a cohort from rural areas of China.

METHODS

The study population included 20,194 adults at baseline (2007-2008) who participated in the Rural Chinese Cohort Study. Cox's proportional hazard regression model was used to analyze the hazard ratios (HRs) and 95% confidence intervals (CIs) of sedentary time and all-cause mortality, and a restricted cubic spline was used to model the dose-response relation. We also carried out a series of sensitivity analyses to verify the robustness of our main results.

RESULTS

The median follow-up duration was 6 years, with a total of 17,265 participants (response rate 85.5%) followed up, and 1,106 deaths observed. Data for 17,048 participants were analyzed, with the mean age of participants being 52.00. Compared with sedentary time <4 h/day group, the risk of all-cause mortality was significantly increased in the 8-11 h/day (HR=1.27, 95%CI:1.03-1.56) and ≥11 h/day groups (HR=1.48, 95%CI:1.20-1.84). With increases in sedentary time, the risk of all-cause mortality increased gradually (Ptrend <0.001). For each 1 h/day increase in sedentary time, the risk of all-cause mortality increased by 3% (HR=1.03, 95%CI: 1.01-1.05). Sensitivity analyses showed our main results were consistent.

CONCLUSIONS

Prolonged sedentary time increases the risk of all-cause mortality in the adult rural Chinese population. Reducing sedentary time may have important implications for reducing mortality risk.

Hypothalamic control of energy expenditure and thermogenesis

Energy expenditure and energy intake need to be balanced to maintain proper energy homeostasis. Energy homeostasis is tightly regulated by the central nervous system, and the hypothalamus is the primary center for the regulation of energy balance. The hypothalamus exerts its effect through both humoral and neuronal mechanisms, and each hypothalamic area has a distinct role in the regulation of energy expenditure. Recent studies have advanced the understanding of the molecular regulation of energy expenditure and thermogenesis in the hypothalamus with targeted manipulation techniques of the mouse genome and neuronal function. In this review, we elucidate recent progress in understanding the mechanism of how the hypothalamus affects basal metabolism, modulates physical activity, and adapts to environmental temperature and food intake changes.

The hypothalamus is a key regulator of metabolism, controlling resting metabolism, activity levels, and responses to external temperature and food intake. The balance between energy intake and expenditure must be tightly controlled, with imbalances resulting in metabolic disorders such as obesity or diabetes. Obin Kwon at Seoul National University College of Medicine and Ki Woo Kim at Yonsei University College of Dentistry, Seoul, both in South Korea, and coworkers reviewed how metabolism is regulated by the hypothalamus, a small hormone-producing brain region. They report that hormonal and neuronal signals from the hypothalamus influence the ratio of lean to fatty tissue, gender-based differences in metabolism, activity levels, and weight gain in response to food intake. They note that further studies to untangle cause-and-effect relationships and other genetic factors will improve our understanding of metabolic regulation.

Orexin, serotonin, and energy balance

The lateral hypothalamus is critical for the control of ingestive behavior and spontaneous physical activity (SPA), as lesion or stimulation of this region alters these behaviors. Evidence points to lateral hypothalamic orexin neurons as modulators of feeding and SPA. These neurons affect a broad range of systems, and project to multiple brain regions such as the dorsal raphe nucleus, which contains serotoninergic neurons (DRN) important to energy homeostasis. Physical activity is comprised of intentional exercise and SPA. These are opposite ends of a continuum of physical activity intensity and structure. Non‐goal‐oriented behaviors, such as fidgeting, standing, and ambulating, constitute SPA in humans, and reflect a propensity for activity separate from intentional activity, such as high‐intensity voluntary exercise. In animals, SPA is activity not influenced by rewards such as food or a running wheel. Spontaneous physical activity in humans and animals burns calories and could theoretically be manipulated pharmacologically to expend calories and protect against obesity. The DRN neurons receive orexin inputs, and project heavily onto cortical and subcortical areas involved in movement, feeding and energy expenditure (EE). This review discusses the function of hypothalamic orexin in energy‐homeostasis, the interaction with DRN serotonin neurons, and the role of this orexin‐serotonin axis in regulating food intake, SPA, and EE. In addition, we discuss possible brain areas involved in orexin–serotonin cross‐talk; the role of serotonin receptors, transporters and uptake‐inhibitors in the pathogenesis and treatment of obesity; animal models of obesity with impaired serotonin‐function; single‐nucleotide polymorphisms in the serotonin system and obesity; and future directions in the orexin–serotonin field.

This article is categorized under:

Metabolic Diseases > Molecular and Cellular Physiology

The active grandparent hypothesis: Physical activity and the evolution of extended human healthspans and lifespans

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.

"Getting Ireland Active"-Application of a Systems Approach to Increase Physical Activity in Ireland Using the GAPPA Framework

Physical activity (PA) promotion is a complex challenge, with the Global Action Plan on Physical Activity (GAPPA) endorsing a systems approach and recommending countries assess existing areas of progress which can be strengthened. This paper reports a process facilitating a systems approach for identifying current good practice and gaps for promoting PA in Ireland. Elements of participatory action research were enabled through 3 stages: (1) aligning examples of actions from Irish policy documents (n = 3) to the GAPPA, (2) workshop with stakeholders across multiple sectors, and (3) review of outputs. Data collected through the workshop were analyzed using a deductive thematic analysis guided by the GAPPA. The policy context in Ireland aligns closely to the GAPPA with the creation of Active Systems the most common strategic objective across policy documents. Forty participants (50% male) took part in the systems approach workshop, which after revision resulted in 80 examples of good practice and 121 actions for greater impact. A pragmatic and replicable process facilitating a systems approach was adopted and showed current Irish policy and practices align with the GAPPA "good practices." The process provides existing areas of progress which can be strengthened, as well as the policy opportunities and practice gaps.

The impact of COVID-19 lockdown on physical activity and weight gain among active adult population in Israel: a cross-sectional study

BACKGROUND

The COVID-19 outbreak holds public health concerns. The stay-at-home increases sedentary behavior, with unintended adverse outcomes. Since organized recreation and sports facilities were closed, we aimed to study how the crisis of closure affected exercise habits and weight gain among the trainee population in Israel. We examined differences in weight gain among individuals with different PA activities and assessed their ability to adapt to digital media as an alternative training structure.

METHODS

A cross-sectional survey consisted of a multiple-choice questionnaire obtained using a web-based survey application. Trainees (1202) who exercised steadily anonymously answered the questionnaire sent by their coaches regarding their activity and weight gain during lockdown times.

RESULTS

Results confirmed that 70% of Israelis trained less than their usual routine, 60% used digital media for training, 55% gained weight. Half of the respondents gained more than 2 kg, with an average increase of 1.2 kg. However, those who exhibited a higher physical activity level gained less weight. Using digital media for training was associated with higher physical activity levels. The aged population was less likely to use digital media.

CONCLUSIONS

Since increased sedentary behavior could increase the risk for potential worsening of health conditions, health agencies should look for strategies, including digital remote media training to promote physical activity and subsequently, preventing the increased burden of future comorbidities worsening by a sedentary lifestyle. Approval: by the Helsinki ethics committee of Sheba Medical Center (6504-19-SMC).

Lifelong enhancement of body mass from adolescent stress in male hamsters

In hamsters, exposure to stress in adulthood causes increased body weight. We addressed how social stress during puberty would impact food intake and body weight. Stressed hamsters started gaining significantly more weight than controls after only two days of stress exposure. Over a two-week period, stressed subjects gained 10% more weight and consumed more food than controls. At the end of the stress period, stressed hamsters collected nearly twice as many palatable sugar pellets from an arena than controls. Stressed subjects presented 15-20% more body fat in mesenteric, inguinal, and retroperitoneal fat pads. In order to assess the duration of these effects, we analyzed data from previous studies keeping hamsters for over two months past the stress period in puberty. Our analysis shows that stressed hamsters stopped gaining more weight after the stress period, but their body weights remained elevated for over two months, consistently weighing 10% more than their non-stressed counterparts. We also analyzed conditioning training data collected after the period of stress in late puberty and early adulthood (P56 to P70) that was part of the original studies. Training consisted of lever pressing for palatable food rewards. At these times, previously stressed hamsters retrieved similar numbers of food pellets from the conditioning chambers, suggesting no difference in appetite after the stress period. These data showing a long-lasting effect of stress on body weight may be relevant to studies on the ontogeny of lifelong obesity.

The effects of breaking sedentary time with different intensity exercise bouts on energy metabolism: A randomized cross-over controlled trial

BACKGROUND AND AIMS

Breaking up sedentary periods, particularly with light activity, increases total energy expenditure (EE), and helps provide better glycemic control. However, the effects of activities of various intensities to interrupt prolonged sedentary time are unclear. The purpose of the present study was to examine potential differences in glycemic control and EE from breaking up sedentary time with short exercise bouts of different intensities.

METHODS AND RESULTS

Nine overweight/obesity young men underwent whole body indirect calorimetry at 19:00 on day 1 and stayed overnight. After awakening on day 2, they performed short duration jogging every 30 min over 8 h (16-time bouts in total) under 3 different conditions with the same running distance: (1) lactate threshold (LT) for 2 min, (2) 60% LT for 200 s, and (3) onset of blood lactate accumulation (OBLA) for 75 s. The 24-h EE and interstitial glucose concentration (from 8:00 to 19:00 on day 2) was continuously measured throughout the trials. The standard deviation during intervention and indexes of postprandial of the interstitial glucose concentration was significantly lower at LT and OBLA than at 60% LT (p < 0.05). The 24-h EE was not significantly different among conditions, but EE at OBLA during intervention was slightly but significantly higher than at 60% LT and LT.

CONCLUSION

Breaking up sedentary time with short-duration jogging at LT and with OBLA intensities may have better glycemic control and increased use of carbohydrate as a fuel, while short-duration a jogging at OBLA intensity may increase EE.

TRIAL REGISTRATION

UMIN000041361.

Laying the Foundation for Pregnancy Physical Activity Profiling: A Framework for Providing Tailored Physical Activity Advice and Guidance to Pregnant Women

The aim of this study was to examine the predictive utility of the theory of planned behaviour (TPB) in explaining pregnant women’s physical activity (PA) intentions and behaviour and to scrutinise the role of past behaviour within this context. Pregnant women (n = 89) completed the pregnancy physical activity questionnaire (PPAQ) and newly developed TPB questionnaire on two separate occasions during their pregnancy. Analyses were carried out in relation to three scenarios. Firstly, when considering the original TPB, intention emerged as the strongest determinant of pregnant women’s PA behaviour. Secondly, controlling for past behaviour attenuated the influence of intention and perceived behavioural control on behaviour, with neither of the original variables providing a unique influence. Finally, the addition of past behaviour added significantly to the prediction of intention with the model as a whole, explaining 85% of the variance in pregnant women’s PA intention, and with past behaviour uniquely contributing 44.8% of the variance. Pregnancy physical activity profiling based on intention and behaviour status is subsequently introduced as a novel and practical framework. This provides healthcare professionals with the opportunity and structure to provide tailored advice and guidance to pregnant women, thereby facilitating engagement with PA throughout motherhood.

Metabolic Adaptations to Weight Loss: A Brief Review

ABSTRACT

Martínez-Gómez, MG and Roberts, BM. Metabolic adaptations to weight loss: A brief review. J Strength Cond Res XX(X): 000-000, 2021-As the scientific literature has continuously shown, body mass loss attempts do not always follow a linear fashion nor always go as expected even when the intervention is calculated with precise tools. One of the main reasons why this tends to happen relies on our body's biological drive to regain the body mass we lose to survive. This phenomenon has been referred to as "metabolic adaptation" many times in the literature and plays a very relevant role in the management of obesity and human weight loss. This review will provide insights into some of the theoretical models for the etiology of metabolic adaptation as well as a quick look into the physiological and endocrine mechanisms that underlie it. Nutritional strategies and dietetic tools are thus necessary to confront these so-called adaptations to body mass loss. Among some of these strategies, we can highlight increasing protein needs, opting for high-fiber foods or programming-controlled diet refeeds, and diet breaks over a large body mass loss phase. Outside the nutritional aspects, it might be wise to increase the physical activity and thus the energy flux of an individual when possible to maintain diet-induced body mass loss in the long term. This review will examine these protocols and their viability in the context of adherence and sustainability for the individual toward successful body mass loss.

Ten things to know about ten cardiovascular disease risk factors

Given rapid advancements in medical science, it is often challenging for the busy clinician to remain up-to-date on the fundamental and multifaceted aspects of preventive cardiology and maintain awareness of the latest guidelines applicable to cardiovascular disease (CVD) risk factors. The “American Society for Preventive Cardiology (ASPC) Top Ten CVD Risk Factors 2021 Update” is a summary document (updated yearly) regarding CVD risk factors. This “ASPC Top Ten CVD Risk Factors 2021 Update” summary document reflects the perspective of the section authors regarding ten things to know about ten sentinel CVD risk factors. It also includes quick access to sentinel references (applicable guidelines and select reviews) for each CVD risk factor section. The ten CVD risk factors include unhealthful nutrition, physical inactivity, dyslipidemia, hyperglycemia, high blood pressure, obesity, considerations of select populations (older age, race/ethnicity, and sex differences), thrombosis/smoking, kidney dysfunction and genetics/familial hypercholesterolemia. For the individual patient, other CVD risk factors may be relevant, beyond the CVD risk factors discussed here. However, it is the intent of the “ASPC Top Ten CVD Risk Factors 2021 Update” to provide a succinct overview of things to know about ten common CVD risk factors applicable to preventive cardiology.

Potential health effects of dietary nitrate supplementation in aging and chronic degenerative disease

In the United States, latest projections indicate the number of adults 65 years of age and older is expected to double by 2050. Given that increased oxidative stress is a hallmark of aging, it is understandable that waning nitric oxide and chronic degenerative disease arise in tandem. To this end, translational evidence-based strategies are needed to mitigate the impending toll on personal and public health. Dietary nitrate supplementation, particularly in the form of beetroot juice, is an active area of inquiry that has gained considerable attention in recent years. Compelling evidence has revealed beetroot juice can elicit potent physiological responses that may offer associated health benefits for multiple clinical disorders including hypertension, dementia, and sarcopenia. Even in the absence of overt disease, age-related impairments in cardiovascular and skeletal muscle function may uniquely benefit from beetroot juice supplementation as evidence has shown blood pressure lowering effects and improved muscle function/contractility - presumably from increased nitric oxide bioavailability. This, in turn, presents a practical opportunity for susceptible populations to support ease of movement and exercise tolerance, both of which may promote free-living physical activity. A theoretical rationale details the potential health effects of dietary nitrate supplementation, wherein a working framework hypothesizes beetroot juice consumption prior to structured exercise training may offer synergistic benefits to aid healthy aging and independent-living among older adults.

Effects of Dietary Protein on Body Composition in Exercising Individuals

Protein is an important component of a healthy diet and appears to be integral to enhancing training adaptations in exercising individuals. The purpose of this narrative review is to provide an evidence-based assessment of the current literature examining increases in dietary protein intake above the recommended dietary allowance (RDA: 0.8 g/kg/d) in conjunction with chronic exercise on body composition (i.e., muscle, fat and bone). We also highlight acute and chronic pre-sleep protein studies as well as the influence of exercise timing on body composition. Overall, a high-protein diet appears to increase muscle accretion and fat loss and may have beneficial effects on bone when combined with exercise. Pre-sleep protein is a viable strategy to help achieve total daily protein goals. Importantly, there appears to be no deleterious effects from a high-protein diet on muscle, fat or bone in exercising individuals.

Strategies for Physical Activity Interventions in the Treatment of Obesity

Physical activity contributes to body weight regulation. At least 150 minutes per week of moderate-to-vigorous intensity physical activity may be needed. When not coupled with dietary restriction, physical activity contributes to an average weight loss of approximately 2 to 3 kg in interventions up to 6 months in duration; when added to modest dietary restriction it adds 20% additional weight loss compared with modest dietary restriction alone. Physical activity is associated with enhanced long-term weight loss and attenuation of weight regain and should be included within clinical and public health approaches to prevent weight regain and to treat obesity.

Occupational, Transport, Leisure-Time, and Overall Sedentary Behaviors and Their Associations with the Risk of Cardiovascular Disease among High-Tech Company Employees

This study examined the associations of overall and domain-specific (i.e., occupational, transport, and leisure-time) sedentary behaviors with cardiovascular disease (CVD) risk factors among high-tech company employees in Taiwan. A total of 363 participants employed at high-tech companies (mean age ± standard deviation: 37.4 ± 7.2 years) completed a questionnaire administered by email regarding their overall, occupational, transport, and leisure-time sedentary behaviors. Self-reported data of height and weight, blood pressure, blood sugar, and total cholesterol levels were also collected in 2018. An adjusted binary logistic regression model was employed in the analysis. After adjusting for sociodemographic variables, high-tech company employees who used a computer (or Internet) for more than 2 h per day during their leisure time were more likely to have CVD risk factors (odds ratio: 1.80; 95% confidence interval: 1.08-3.00). No significant associations with CVD risk factors were detected for total sedentary time, occupational sitting, television viewing time, and transport-related sitting. Despite the nature of cross-sectional design in this study, our findings may have considerable implications for intervention designers and policymakers of Taiwan. Developing effective strategies for limiting leisure-time computer use should be considered for the prevention of CVD among high-tech company employees.

Whey protein isolate or concentrate combined with concurrent training does not augment performance, cardiorespiratory fitness, or strength adaptations

BACKGROUND

Protein supplementation alters both strength and endurance training adaptations individually; however less is known regarding protein supplementation during concurrent training. The primary purpose of this study was to investigate the effects of whey protein supplementation during six weeks of concurrent training on performance, cardiorespiratory fitness, and maximal strength adaptations, as well as acute hormonal and immune responses. A secondary purpose was to explore the effects of two types of whey protein powders on these latter variables.

METHODS

Thirty-one participants were randomly assigned to supplement with a placebo (PLA; N.=10), whey protein isolate (WPI; N.=10), or whey protein concentrate (WPC; N.=11) in addition to their habitual diet. Total protein intake was 1.2, 3.5, and 3.5 g/kg/day for PLA, WPI, WPC groups, respectively. Exercise testing was performed before and after 6 weeks of concurrent training. Blood samples were obtained at rest, and 5 and 60 minutes after a simulated 2000 m rowing race prior to and after training.

RESULTS

There were similar but significant improvements in cardiorespiratory fitness (PLA +7.5%; WPI +3.9%; WPC +6.9%), upper body strength (PLA +5.5%; WPI +5.1%; WPC +6.7%), lower body strength (PLA +13.6%; WPI +9.4%; WPC +14.1%) and 2000m rowing performance (PLA -2.5%; WPI -2.3%; WPC -2.3%) in all groups, P<0.05. As well, hormonal and immune responses to acute exercise were similar over time and between groups.

CONCLUSIONS

Whey protein supplementation did not differentially influence performance, cardiorespiratory fitness, upper and lower body strength, immune or hormonal adaptations following 6 weeks of concurrent training.

Ten things to know about ten cardiovascular disease risk factors ("ASPC Top Ten - 2020")

Preventive cardiology involves understanding and managing multiple cardiovascular disease (CVD) risk factors. Given the rapid advancements in medical science, it may be challenging for the busy clinician to remain up-to-date on the multifaceted and fundamental aspects of CVD prevention, and maintain awareness of the newest applicable guidelines. The "American Society for Preventive Cardiology (ASPC) Top Ten 2020" summarizes ten essential things to know about ten important CVD risk factors, listed in tabular formats. The ten CVD risk factors include unhealthful nutrition, physical inactivity, dyslipidemia, hyperglycemia, high blood pressure, obesity, considerations of select populations (older age, race/ethnicity, and gender), thrombosis/smoking, kidney dysfunction and genetics/familial hypercholesterolemia. For the individual patient, other CVD risk factors may be relevant, beyond the CVD risk factors discussed here. However, it is the intent of the "ASPC Top Ten 2020" to provide a succinct overview of things to know about ten common CVD risk factors applicable to preventive cardiology.

Association of total sedentary behaviour and television viewing with risk of overweight/obesity, type 2 diabetes and hypertension: A dose-response meta-analysis

AIMS

To explore the quantitative dose-response association of total sedentary behaviour and television viewing with overweight/obesity, type 2 diabetes and hypertension in a meta-analysis.

MATERIALS AND METHODS

We searched three databases to identify English-language reports that assessed the association of total sedentary behaviour or television viewing with the aforementioned health outcomes. Restricted cubic splines were used to evaluate possible linear or non-linear associations of total sedentary behaviour and television viewing with these health outcomes.

RESULTS

We included 48 articles (58 studies) with a total of 1 071 967 participants in the meta-analysis; 21 (six cohort and 15 cross-sectional) studies examined the association of total sedentary behaviour with overweight/obesity, 23 (13 cohort and 10 cross-sectional) studies examined the association with type 2 diabetes and 14 (one cohort and 13 cross-sectional) studies examined the association with hypertension. We found linear associations between total sedentary behaviour and type 2 diabetes (P_{non-linearity} = 0.190) and hypertension (P_{non-linearity} = 0.225) and a non-linear association between total sedentary behaviour and overweight/obesity (P_{non-linearity} = 0.003). For each 1-h/d increase in total sedentary behaviour, the risk increased by 5% for type 2 diabetes and 4% for hypertension. We also found linear associations between television viewing and type 2 diabetes (P_{non-linearity} = 0.948) and hypertension (P_{non-linearity} = 0.679) and a non-linear association for overweight/obesity (P_{non-linearity} = 0.007). For each 1-h/d increase in television viewing, the risk increased by 8% for type 2 diabetes and 6% for hypertension.

CONCLUSIONS

High levels of total sedentary behaviour and television viewing were associated with overweight/obesity, type 2 diabetes and hypertension.

Energy Compensation Following a Supervised Exercise Intervention in Women Living With Overweight/Obesity Is Accompanied by an Early and Sustained Decrease in Non-structured Physical Activity

Background/Objectives

Body composition (BC) does not always vary as a function of exercise induced energy expenditure (exercise EE – resting EE). Energy balance variables were measured to understand energy compensation (EC) in response to an exercise intervention performed at low (LOW) or moderate (MOD) intensity.

Subjects/Methods

Twenty-one women with overweight/obesity (33 ± 5 kg/m²; 29 ± 10 yrs; 31 ± 4 ml O₂/kg/min) were randomized to a 3-month LOW or MOD (40 or 60% of VȮ_2reserve, respectively) matched to expend 1500 kcal/week (compliance = 97 ± 5%). Body energy stores (DXA), energy intake (EI) (food menu and food diaries), resting EE (indirect calorimetry), total EE (doubly-labeled water), time spent in different activities (accelerometers), appetite (visual analog scale), eating behavior traits and food reward (liking and wanting) were assessed at baseline, after weeks 1 and 2 and at the end of the 3-month exercise intervention.

Results

EC based on BC changes (fat mass and fat-free mass) was 49 ± 79% and 161 ± 88% in LOW and MOD groups, respectively (p = 0.010). EI did not change significantly during the intervention. However, eating behavior traits and food reward had changed by the end of the 3-month supervised exercise. Non-structured physical activity (NSPA) decreased across the intervention (p < 0.002), independent of the intensity of the exercise training.

Conclusion

Women with overweight/obesity training at LOW presented lower EC for a given energy cost of exercise. Our results strongly suggest that NSPA plays a major role in mediating the effects of exercise on energy balance and ultimately on changes in BC.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier ISRCTN31641049.

Biomarkers of cardiometabolic health are associated with body composition characteristics but not physical activity in persons with spinal cord injury

OBJECTIVE

To examine (i) the associations between physical activity dimensions, cardiorespiratory fitness and body composition and, (ii) the associations between physical activity dimensions, cardiorespiratory fitness, body composition and biomarkers of cardiometabolic health in persons with spinal cord injury (SCI).

METHODS

A cross-sectional prospective cohort study with 7-day follow-up was conducted. Body composition, cardiorespiratory fitness and biomarkers of cardiometabolic health were measured in thirty-three participants with SCI (> 1 year post injury). Physical activity dimensions were objectively assessed over 7-days.

RESULTS

Activity energy expenditure (r =.43), physical activity level (r =.39), and moderate-to-vigorous physical activity (MVPA) (r =.48) were significantly (P < 0.001) associated with absolute (L/min) peak oxygen uptake (⩒O₂ peak). ⩒O₂ peak was significantly higher in persons performing ≥150 MVPA minutes/week compared to <40 minutes/week (P = 0.003). Individual physical activity dimensions were not significantly associated with biomarkers of cardiometabolic health. However, body composition characteristics (BMI, waist and hip circumference) showed significant (P < 0.04), moderate (r >.30) associations with parameters of metabolic regulation, lipid profiles and inflammatory biomarkers. Relative ⩒O₂ peak (ml/kg/min) was moderately associated with only insulin sensitivity (r = 0.37, P = 0.03).

CONCLUSIONS

Physical activity dimensions are associated with cardiorespiratory fitness; however, stronger and more consistent associations suggest that poor cardiometabolic health is associated with higher body fat content. Given these findings, the regulation of energy balance should be an important consideration for researchers and clinicians looking to improve cardiometabolic health in persons with SCI.

Randomized controlled trial for assessment of Internet of Things system to guide intensive glucose control in diabetes outpatients: Nagoya Health Navigator Study protocol

The Internet of Things (IoT) allows collecting vast amounts of health-relevant data such as daily activity, body weight (BW), and blood pressure (BP) automatically. The use of IoT devices to monitor diabetic patients has been studied, but could not evaluate IoT-dependent effects because health data were not measured in control groups. This multicenter, open-label, randomized, parallel group study will compare the impact of intensive health guidance using IoT and conventional medical guidance on glucose control. It will be conducted in outpatients with type 2 diabetes for a period of 6 months. IoT devices to measure amount of daily activity, BW, and BP will be provided to IoT group patients. Healthcare professionals (HCPs) will provide appropriate feedback according to the data. Non-IoT control, patients will be given measurement devices that do not have a feedback function. The primary outcome is glycated hemoglobin at 6 months. The study has already enrolled 101 patients, 50 in the IoT group and 51 in the non-IoT group, at the two participating outpatient clinics. The baseline characteristics of two groups did not differ, except for triglycerides. This will be the first randomized, controlled study to evaluate IoT-dependent effects of intensive feedback from HCPs. The results will validate a new method of health-data collection and provision of feedback suitable for diabetes support with increased effectiveness and low cost.

Non-exercise activity thermogenesis (NEAT): a component of total daily energy expenditure

[Purpose]

The purpose of this review is to promote awareness of non-exercise activity thermogenesis (NEAT) as a new strategy to increase energy expenditure, and to manage obesity.

[Methods]

The content of this review is based on a literature search of PubMed and the Google Scholar search engine, using the search terms obesity, energy expenditure, non-exercise activity thermogenesis (NEAT), and sitting disease.

[Results]

Daily energy expenditure is of great interest because most obese individuals have no exercise activity-related thermogenesis (EAT); thus their physical activity-related energy expenditure (PEE) is comprised almost entirely of NEAT. Consequently, NEAT represents the main variable component of daily total energy expenditure (TEE); this varies considerably, both within among individuals. These somewhat unplanned and unstructured low level physical activities are associated with energy expenditure in excess of the resting metabolic rate (RMR). They may therefore have the potential to stimulate greater energy expenditure over time with a higher rate of adherence.

[Conclusion]

In conclusion, NEAT is a highly variable component of daily TEE and a low level of NEAT is associated with obesity. NEAT enhances lifestyle, and variations in individual and environmental factors can significantly affect daily energy expenditure. Therefore, well designed longitudinal studies that focus on personal behavioral approaches and re-engineered environments to increase NEAT should be conducted in the future.

Exercise Therapy for Patients With Type 2 Diabetes: A Narrative Review

To achieve excellent glycemic control in patients with type 2 diabetes, an adequate prescription of exercise therapy is required. The meta-analyses proposed that high-intensity training improves metabolic parameters in patients with pre-diabetes or type 2 diabetes and low physical activity is associated with an increased risk of incident type 2 diabetes. Here, we would introduce literatures about effects of physical activity on mortality, cardiovascular events, and metabolic parameters, to encourage understanding of exercise therapy, and then describe how to prescribe exercise therapy for patients with type 2 diabetes. We also show the usefulness of non-exercise activity thermogenesis for diabetic patients who cannot perform volitional sporting-like exercise because of diabetic complication and/or comorbidity, by presenting results of our previous studies.

The Influence of Life Events and Psychological Stress on Objectively Measured Physical Activity: A 12-Month Longitudinal Study

BACKGROUND

This study examined how life event occurrences and stressfulness influence objectively measured light through vigorous physical activity (PA) among young adults.

METHODS

Every 3 months over a 12-month period, 404 healthy young adults completed questionnaires on the occurrence and stress of 16 life events and wore an accelerometer for 10 days.

RESULTS

A modest positive relationship was seen between cumulative life event occurrences [between effect: β = 22.2 (9.7) min/d, P = .02] and cumulative stress [between effect: β = 7.6 (2.9) min/d, P = .01] with light through vigorous PA among men. When considering events individually, job change, starting a first job, beginning a mortgage, and changes in a relationship influenced men's PA. For women, mortgage, starting a first job, job change, and engagement had significant associations. Life event stressfulness influenced PA in women more than in men. For men, stress from changes in a relationship or job positively influenced PA. Stress of a mortgage, quitting a job, changing jobs or a first job influenced women's PA.

CONCLUSION

Considering each life event individually was more informative than the summation of life events or summation of stress. Specific life events substantially altered PA, and this change varied by gender, direction of association, and PA intensity and duration.

Differences of energy expenditure while sitting versus standing: A systematic review and meta-analysis

Background Replacing sitting with standing is one of several recommendations to decrease sedentary time and increase the daily energy expenditure, but the difference in energy expenditure between standing versus sitting has been controversial. This systematic review and meta-analysis aimed to determine this difference. Designs and methods We searched Ovid MEDLINE, Ovid Embase Scopus, Web of Science and Google Scholar for observational and experimental studies that compared the energy expenditure of standing versus sitting. We calculated mean differences and 95% confidence intervals using a random effects model. We conducted different predefined subgroup analyses based on characteristics of participants and study design. Results We identified 658 studies and included 46 studies with 1184 participants for the final analysis. The mean difference in energy expenditure between sitting and standing was 0.15 kcal/min (95% confidence interval (CI) 0.12-0.17). The difference among women was 0.1 kcal/min (95% CI 0.0-0.21), and was 0.19 kcal/min (95% CI 0.05-0.33) in men. Observational studies had a lower difference in energy expenditure (0.11 kcal/min, 95% CI 0.08-0.14) compared to randomised trials (0.2 kcal/min, 95% CI 0.12-0.28). By substituting sitting with standing for 6 hours/day, a 65 kg person will expend an additional 54 kcal/day. Assuming no increase in energy intake, this difference in energy expenditure would be translated into the energy content of about 2.5 kg of body fat mass in 1 year. Conclusions The substitution of sitting with standing could be a potential solution for a sedentary lifestyle to prevent weight gain in the long term. Future studies should aim to assess the effectiveness and feasibility of this strategy.

Spontaneous Physical Activity Defends Against Obesity

PURPOSE OF REVIEW

Spontaneous physical activity (SPA) is a physical activity not motivated by a rewarding goal, such as that associated with food-seeking or wheel-running behavior. SPA is often thought of as only "fidgeting," but that is a mischaracterization, since fidgety behavior can be linked to stereotypies in neurodegenerative disease and other movement disorders. Instead, SPA should be thought of as all physical activity behavior that emanates from an unconscious drive for movement.

RECENT FINDINGS

An example of this may be restless behavior, which can include fidgeting and gesticulating, frequent sit-to-stand movement, and more time spent standing and moving. All physical activity burns calories, and as such, SPA could be manipulated as a means to burn calories, and defend against weight gain and reduce excess adiposity. In this review, we discuss human and animal literature on the use of SPA in reducing weight gain, the neuromodulators that could be targeted to this end, and future directions in this field.

Traveling by Private Motorized Vehicle and Physical Fitness in Taiwanese Adults

BACKGROUND

Although the time spent sitting in motorized vehicles has been determined to be adversely associated with cardiometabolic health, its association with other health indicators remains unclear.

PURPOSE

This study examined associations between traveling by private motorized vehicle and 4 indicators of physical fitness in adults.

METHOD

Data from 52,114 Taiwanese adults aged 20 to 65 years who participated in the 2013 National Adults Fitness Survey were used. The examined variables were height, body mass, and performance in modified sit-and-reach (flexibility), bent-leg sit-up (abdominal muscular strength and endurance), and a 3-min step test (cardiorespiratory endurance). Participants were asked on how many days they had used a private car or motorcycle for traveling from place to place and categorized as non-, occasional, and daily private motorized vehicle travelers. Logistic and linear regression models were used to examine associations between the categories of using private motorized vehicles to travel and physical fitness performance.

RESULTS

After an adjustment for potential demographic and behavioral confounders, daily traveling by private motorized vehicle was associated with a higher probability of overweight (odds ratio = 1.18), lower performance of abdominal muscular strength and endurance (-0.37 times/min), and lower cardiorespiratory fitness (-0.60 physical fitness index) than was traveling that did not involve private motorized vehicles.

CONCLUSION

The results suggest that in addition to unfavorable cardiorespiratory fitness and a risk of overweight, daily traveling by private motorized vehicle is associated with poor performance in abdominal muscular strength and endurance.

Sedentary behaviour is a key determinant of metabolic inflexibility

Metabolic flexibility is defined as the ability to adapt substrate oxidation rates in response to changes in fuel availability. The inability to switch between the oxidation of lipid and carbohydrate appears to be an important feature of chronic disorders such as obesity and type 2 diabetes. Laboratory assessment of metabolic flexibility has traditionally involved measurement of the respiratory quotient (RQ) by indirect calorimetry during the fasted to fed transition (e.g. mixed meal challenge) or during a hyperinsulinaemic-euglycaemic clamp. Under these controlled experimental conditions, 'metabolic inflexibility' is characterized by lower fasting fat oxidation (higher fasting RQ) and/or an impaired ability to oxidize carbohydrate during feeding or insulin-stimulated conditions (lower postprandial or clamp RQ). This experimental paradigm has provided fundamental information regarding the role of substrate oxidation in the development of obesity and insulin resistance. However, the key determinants of metabolic flexibility among relevant clinical populations remain unclear. Herein, we propose that habitual physical activity levels are a primary determinant of metabolic flexibility. We present evidence demonstrating that high levels of physical activity predict metabolic flexibility, while physical inactivity and sedentary behaviours trigger a state of metabolic 'inflexibility', even among individuals who meet physical activity recommendations. Furthermore, we describe alternative experimental approaches to studying the concept of metabolic flexibility across a range of activity and inactivity. Finally, we address the promising use of strategies that aim to reduce sedentary behaviours as therapy to improve metabolic flexibility and reduce weight gain risk.

Attenuating the Biologic Drive for Weight Regain Following Weight Loss: Must What Goes Down Always Go Back Up?

Metabolic adaptations occur with weight loss that result in increased hunger with discordant simultaneous reductions in energy requirements—producing the so-called energy gap in which more energy is desired than is required. The increased hunger is associated with elevation of the orexigenic hormone ghrelin and decrements in anorexigenic hormones. The lower total daily energy expenditure with diet-induced weight loss results from (1) a disproportionately greater decrease in circulating leptin and resting metabolic rate (RMR) than would be predicted based on the decline in body mass, (2) decreased thermic effect of food (TEF), and (3) increased energy efficiency at work intensities characteristic of activities of daily living. These metabolic adaptations can readily promote weight regain. While more experimental research is needed to identify effective strategies to narrow the energy gap and attenuate weight regain, some factors contributing to long-term weight loss maintenance have been identified. Less hunger and greater satiation have been associated with higher intakes of protein and dietary fiber, and lower glycemic load diets. High levels of physical activity are characteristic of most successful weight maintainers. A high energy flux state characterized by high daily energy expenditure and matching energy intake may attenuate the declines in RMR and TEF, and may also result in more accurate regulation of energy intake to match daily energy expenditure.

Association of Motorcycle Use with Risk of Overweight in Taiwanese Urban Adults

Sedentary transport is known to adversely affect health. Few studies have focused on motorcycle use. This study examines the association of motorcycle use with overweight in urban adults in Taiwan. Cross-sectional data from 1069 Taiwanese adults aged 20–64 years in three urban cities were collected in 2015. Data on self-reported body mass index, time spent in motorcycle use, lifestyle behavioral factors, and sociodemographic variables were obtained. Unadjusted and adjusted logistic regression models were applied. In Model 1, adults who spent more time using a motorcycle (third quartile, odds ratio (OR) = 1.17; fourth quartile, OR = 1.60) were more likely to be overweight compared with the first quartile. In Model 2, after adjusting for the covariates, only the fourth quartile of motorcycle use (OR = 1.50) was associated with a higher risk of overweight. Higher time spent in motorcycle use is related to higher risk of being overweight, even after adjustment for potential demographic and behavioral confounders. Intervention and behavioral change strategies targeting motorcycle use should be considered.

The associations of resting metabolic rate with chronic conditions and weight loss

The aim of this study was to examine the associations between baseline and changes in resting metabolic rate (RMR) with chronic condition(s) and weight loss (WL). Sex stratified analysis was undertaken on 393 adults from the Wharton Weight Management Clinics. The association between baseline RMR and WL was examined adjusting for age, BMI, ethnicity and treatment time. The association between changes in RMR (ΔRMR) and WL was also examined adjusting for baseline RMR and above covariates. Models were further adjusted for high glucose, triglycerides, blood pressure, low-density lipoprotein (LDL) and low high-density lipoprotein (HDL). While men (6.0 ± 8.6 kg) and women (5.6 ± 8.3 kg) had significant WL throughout the intervention, their measured decreases in RMR (-48 ± 322 kcal and -5 ± 322 kcal, respectively) were non-significant (P > 0.05). Individuals with a high blood pressure had a higher baseline RMR and women with a high LDL had a lower baseline RMR than those without the chronic condition (P < 0.05). Regardless of sex, WL was not significantly associated with baseline RMR or ΔRMR (P > 0.05) in both models. Participants with a low baseline RMR do not appear to be at a disadvantage for WL. Further, WL can occur without decreases in RMR in populations with high levels of obesity and obesity-related comorbidities.

Maintaining Weight Loss by Decreasing Sedentary Time: A Patient and Physician's Perspective

This article, co-authored by a patient living with obesity and his obesity medicine specialist, reviews how the patient has successfully lost 200 lb and maintained that loss for over a decade. This was achieved primarily with a behavioral intervention including support visits, a structured food plan, and changes in his physical activity. He did not undergo bariatric surgery. For the majority of this time, he was not treated with anti-obesity medication. This article will review how the patient lost the weight and kept it off, particularly in relationship to the importance of decreasing sedentary time.

Behavioral Medicine Review: Weight Control in a Land of Milk and Honey

Obesity and its cardiometabolic comorbidities are on a skyrocketing trajectory with ominous public health implications. Focusing on primary care as a microcosm of the broader obesity crisis, this review discusses considerations for the prevention and management of obesity and its associated risks.

Lower rate-pressure product during submaximal walking: a link to fatigue improvement following a physical activity intervention among breast cancer survivors

PURPOSE

Research showing a link between exercise-induced changes in aerobic fitness and reduced fatigue after a cancer diagnosis has been inconsistent. We evaluated associations of fatigue and rate-pressure product (RPP), a reliable index of myocardial oxygen demand, at rest and during submaximal walking following a physical activity intervention among post-primary treatment breast cancer survivors (BCS).

METHODS

Secondary analyses of 152 BCS in a randomized controlled trial testing a physical activity intervention (INT) versus usual care (UC) were performed. The INT group completed counseling/group discussions along with supervised exercise sessions tapered to unsupervised exercise. Evaluations were made at baseline and immediately post-intervention (M3) on measures of physical activity (accelerometry), graded walk test, and average fatigue over the previous 7 days. RPP was calculated by dividing the product of heart rate and systolic blood pressure by 100.

RESULTS

Resting and submaximal RPPs were significantly improved in both groups at M3; however, the magnitude of change (∆) was greater in the INT group from stage 1 (∆RPP1; INT -13 ± 17 vs. UC -7 ± 18; p = 0.03) through stage 4 (∆RPP4; INT -21 ± 26 vs. UC -9 ± 24; p < 0.01) of the walk test. The INT group reported significantly reduced fatigue (INT -0.7 ± 2.0 vs. UC +0.1 ± 2.0; p = 0.02) which was positively associated with ∆RPP during stages 2-4 of the walk test but not ∆aerobic fitness.

CONCLUSIONS

Lower RPP during submaximal walking was significantly associated with reduced fatigue in BCS.

IMPLICATIONS FOR CANCER SURVIVORS

Exercise/physical activity training programs that lower the physiological strain during submaximal walking may produce the largest improvements in reported fatigue.

Daily physical activity and type 2 diabetes: A review

Physical activity improves glycemic control and reduces the risk of cardiovascular disease (CVD) and mortality in patients with type 2 diabetes (T2D). Moderate to vigorous physical activity is recommended to manage T2D; however, patients with T2D can be physically weak, making it difficult to engage in the recommended levels of physical activity. Daily physical activity includes various activities performed during both occupational and leisure time such as walking, gardening, and housework that type 2 diabetic patients should be able to perform without considerable physical burden. This review focuses on the association between daily physical activity and T2D. Walking was the most common form of daily physical activity, with numerous studies demonstrating its beneficial effects on reducing the risk of T2D, CVD, and mortality. Walking for at least 30 min per day was shown to reduce the risk of T2D by approximately 50%. Additionally, walking was associated with a reduction in mortality. In contrast, evidence was extremely limited regarding other daily physical activities such as gardening and housework in patients with T2D. Recent studies have suggested daily physical activity, including non-exercise activity thermogenesis, to be favorably associated with metabolic risks and mortality. However, well-designed longitudinal studies are warranted to elucidate its effects on overall health.

A workplace intervention designed to interrupt prolonged occupational sitting

Purpose

– The purpose of this paper is to investigate the effectiveness of a workplace intervention designed to interrupt prolonged occupational sitting time (POST) and its impact on the self-reported health of a cohort of desk-based employees.

Design/methodology/approach

– In total, 43 participants received an interactive computer-based software intervention for 26 weeks. For the first 13 weeks the intervention passively prompted the participants to interrupt POST and perform brief bouts of non-purposeful movement. The second 13 weeks involved the passivity of the intervention being removed, with the intervention only accessible voluntarily by the participant. This approach was adopted to determine the sustainability of the intervention to change workplace health behaviour.

Findings

– ANOVA results revealed a significant interaction between group and test occasion, F(2, 42)=2.79, p < 0.05, such that the experimental group increased their total health from pre-test to post-test (13 weeks), and to second post-test (26 weeks) with a medium effect size of Cohen’s d=0.37.

Research limitations/implications

– An action research approach was implemented for this study, and hence the participants were organised into one group. Based on a communitarian model, the intervention aimed to monitor how desk-based employees adapted to specific health behaviours, and therefore a control group was not included.

Practical implications

– Passively prompting desk-based employees to interrupt POST and perform non-purposeful movement at work improved self-reported health. Participant perceptions of health were maintained following the removal of the passive feature of the intervention.

Social implications

– Interventions predicated on a social ecological model that modify how employees interact with the workplace environment might provide a framework for health behaviour change in populations where sitting is customary.

Originality/value

– The passive approach used in this study removed the individual decision-making process to engage in health behaviour change, and established a sustainable effect on participant health.

Exercise Training and Energy Expenditure following Weight Loss

PURPOSE

This study aims to determine the effects of aerobic or resistance training on activity-related energy expenditure (AEE; kcal·d(-1)) and physical activity index (activity-related time equivalent (ARTE)) following weight loss. It was hypothesized that weight loss without exercise training would be accompanied by decreases in AEE, ARTE, and nontraining physical activity energy expenditure (nonexercise activity thermogenesis (NEAT)) and that exercise training would prevent decreases in free-living energy expenditure.

METHODS

One hundred forty premenopausal women had an average weight loss of 25 lb during a diet (800 kcal·d(-1)) of furnished food. One group aerobically trained 3 times per week (40 min·d(-1)), another group resistance-trained 3 times per week (10 exercises/2 sets × 10 repetitions), and the third group did not exercise. Dual-energy x-ray absorptiometry was used to measure body composition, indirect calorimetry was used to measure resting energy expenditure (REE) and walking energy expenditure, and doubly labeled water was used to measure total energy expenditure (TEE). AEE, ARTE, and nontraining physical activity energy expenditure (NEAT) were calculated.

RESULTS

TEE, REE, and NEAT all decreased following weight loss for the no-exercise group, but not for aerobic and resistance trainers. Only REE decreased in the two exercise groups. Resistance trainers increased ARTE. HR and oxygen uptake while walking on the flat and up a grade were consistently related to TEE, AEE, NEAT, and ARTE.

CONCLUSIONS

Exercise training prevents a decrease in energy expenditure, including free-living energy expenditure separate from exercise training, following weight loss. Resistance training increases physical activity, whereas economy/ease of walking is associated with increased TEE, AEE, NEAT, and ARTE.

Imbalanced insulin action in chronic over nutrition: Clinical harm, molecular mechanisms, and a way forward

The growing worldwide prevalence of overnutrition and underexertion threatens the gains that we have made against atherosclerotic cardiovascular disease and other maladies. Chronic overnutrition causes the atherometabolic syndrome, which is a cluster of seemingly unrelated health problems characterized by increased abdominal girth and body-mass index, high fasting and postprandial concentrations of cholesterol- and triglyceride-rich apoB-lipoproteins (C-TRLs), low plasma HDL levels, impaired regulation of plasma glucose concentrations, hypertension, and a significant risk of developing overt type 2 diabetes mellitus (T2DM). In addition, individuals with this syndrome exhibit fatty liver, hypercoagulability, sympathetic overactivity, a gradually rising set-point for body adiposity, a substantially increased risk of atherosclerotic cardiovascular morbidity and mortality, and--crucially--hyperinsulinemia. Many lines of evidence indicate that each component of the atherometabolic syndrome arises, or is worsened by, pathway-selective insulin resistance and responsiveness (SEIRR). Individuals with SEIRR require compensatory hyperinsulinemia to control plasma glucose levels. The result is overdrive of those pathways that remain insulin-responsive, particularly ERK activation and hepatic de-novo lipogenesis (DNL), while carbohydrate regulation deteriorates. The effects are easily summarized: if hyperinsulinemia does something bad in a tissue or organ, that effect remains responsive in the atherometabolic syndrome and T2DM; and if hyperinsulinemia might do something good, that effect becomes resistant. It is a deadly imbalance in insulin action. From the standpoint of human health, it is the worst possible combination of effects. In this review, we discuss the origins of the atherometabolic syndrome in our historically unprecedented environment that only recently has become full of poorly satiating calories and incessant enticements to sit. Data are examined that indicate the magnitude of daily caloric imbalance that causes obesity. We also cover key aspects of healthy, balanced insulin action in liver, endothelium, brain, and elsewhere. Recent insights into the molecular basis and pathophysiologic harm from SEIRR in these organs are discussed. Importantly, a newly discovered oxide transport chain functions as the master regulator of the balance amongst different limbs of the insulin signaling cascade. This oxide transport chain--abbreviated 'NSAPP' after its five major proteins--fails to function properly during chronic overnutrition, resulting in this harmful pattern of SEIRR. We also review the origins of widespread, chronic overnutrition. Despite its apparent complexity, one factor stands out. A sophisticated junk food industry, aided by subsidies from willing governments, has devoted years of careful effort to promote overeating through the creation of a new class of food and drink that is low- or no-cost to the consumer, convenient, savory, calorically dense, yet weakly satiating. It is past time for the rest of us to overcome these foes of good health and solve this man-made epidemic.