Substrate metabolism in male astronauts onboard the International Space Station: the ENERGY study.

Bedrest shifts fasting and postprandial fuel selection towards carbohydrate use over lipids, potentially affecting astronauts' performance and health. We investigated whether this change occurs in astronauts after at least 3 months onboard the International Space Station (ISS). We further explored the associations with diet, physical activity (PA), and body composition. Before and during spaceflight, respiratory quotient (RQ), carbohydrate, and fat oxidation were measured by indirect calorimetry before and following a standardized meal in 11 males (age = 45.7 [SD 7.7] years, BMI = 24.3 [2.1] kg m-²). Postprandial substrate use was determined by 0-to-260 min postprandial incremental area under the curve (iAUC) of nutrient oxidation and the difference between maximal postprandial and fasting RQ (ΔRQ). Food quotient (FQ) was calculated from diet logs. Fat (FM) and fat-free mass (FFM) were measured by hydrometry and PA by accelerometry and diary logs. Spaceflight increased fasting RQ (P = 0.01) and carbohydrate oxidation (P = 0.04) and decreased fasting lipid oxidation (P < 0.01). An increase in FQ (P < 0.001) indicated dietary modifications onboard the ISS. Spaceflight-induced RQ changes adjusted for ground RQ correlated with inflight FQ (P < 0.01). In postprandial conditions, nutrient oxidation and ΔRQ were unaffected on average. Lipid oxidation changes negatively correlated with FFM changes and inflight aerobic exercise and positively with FM changes. The opposite was observed for carbohydrate oxidation. ΔRQ changes were negatively and positively related to FM and FFM changes, respectively. In conclusion, fasting substrate oxidation shift observed during spaceflight may primarily result from dietary modifications. Between-astronaut variability in postprandial substrate oxidation depends on body composition changes and inflight PA.

The impact of 60 days of -6° head down tilt bed rest on mitochondrial content, respiration and regulators of mitochondrial dynamics.

It is unclear how skeletal muscle metabolism and mitochondrial function adapt to long duration bed rest and whether changes can be prevented by nutritional intervention. The present study aimed (1) to assess the effect of prolonged bed rest on skeletal muscle mitochondrial function and dynamics and (2) to determine whether micronutrient supplementation would mitigate the adverse metabolic effect of bed rest. Participants were maintained in energy balance throughout 60 days of bed rest with micronutrient supplementation (INT) (body mass index: 23.747 ± 1.877 kg m-2 ; 34.80 ± 7.451 years; n = 10) or without (control) (body mass index: 24.087 ± 2.088 kg m-2 ; 33.50 ± 8.541 years; n = 10). Indirect calorimetry and dual-energy x-ray absorptiometry were used for measures of energy expenditure, exercise capacity and body composition. Mitochondrial respiration was determined by high-resolution respirometry in permeabilized muscle fibre bundles from vastus lateralis biopsies. Protein and mRNA analysis further examined the metabolic changes relating to regulators of mitochondrial dynamics induced by bed rest. INT was not sufficient in preserving whole body metabolic changes conducive of a decrease in body mass, fat-free mass and exercise capacity within both groups. Mitochondrial respiration, OPA1 and Drp1 protein expression decreased with bed rest, with an increase pDrp1s616 . This reduction in mitochondrial respiration was explained through an observed decrease in mitochondrial content (mtDNA:nDNA). Changes in regulators of mitochondrial dynamics indicate an increase in mitochondrial fission driven by a decrease in inner mitochondrial membrane fusion (OPA1) and increased pDrp1s616 . KEY POINTS: Sixty days of -6° head down tilt bed rest leads to significant changes in body composition, exercise capacity and whole-body substrate metabolism. Micronutrient supplementation throughout bed rest did not preserve whole body metabolic changes. Bed rest results in a decrease in skeletal muscle mitochondrial respiratory capacity, mainly as a result of an observed decrease in mitochondrial content. Prolonged bed rest ensues changes in key regulators of mitochondrial dynamics. OPA1 and Drp1 are significantly reduced, with an increase in pDrp1s616 following bed rest indicative of an increase in mitochondrial fission. Given the reduction in mitochondrial content following 60 days of bed rest, the maintenance of regulators of mitophagy in line with the increase in regulators of mitochondrial fission may act to maintain mitochondrial respiration to meet energy demands.

Nothing in Excess: Physical Activity, Health, and Life World in Senegalese Fulani Male Pastoralists, a Mixed Method Approach.

OBJECTIVES: The goal of this study was to evaluate the application of the short form of the International Physical Activity Questionnaire Survey (IPAQ-SF) in the rural Senegalese Fulani pastoralist population by combining quantitative and qualitative methods. DESIGN AND PARTICIPANTS: For the quantitative method, 101 men completed the IPAQ-SF questionnaire measuring moderate, vigorous, and walking physical activity. Self-rated health, BMI, and sociodemographic variables were also collected. With regard to the qualitative methods, a total of 22 participants were recruited and interviewed. Four themes were addressed, including (i) physical activity (PA) and its definition, description, related experiences, and representations of social actors; (ii) PA and health; (iii) PA and sport; and (iv) the body and Fulani world of life (i.e., Pulaagu/Ndimaagu). RESULTS: Sahelian herders have a high level of self-reported PA and a low amount of daily sitting time. The measure of PA as proposed by the IPAQ-SF is not adapted to the Senegalese Ferlo pastoralists, mainly because this scale gives too much importance to leisure-time PA, perceived as unproductive energy expenditure, which is factually and symbolically antinomic to the Fulani lifeworld. Thus, neither intense nor moderate PA is related to self-rated health. However, sedentary lifestyles are linked to self-rated health and, therefore, to mortality and morbidity in Fulani pastoralists. Finally, walking, which is the dominant PA during transhumance and herd surveillance, is related to BMI. It therefore represents a protective factor against the occurrence of overweight and associated chronic non-communicable diseases. CONCLUSION: The mixed method approach developed in this study has shown that the IPAQ-SF is not a valid measure of PA in the population of Fulani male herders from the Ferlo region, given that unproductive energy expenditure is incompatible with the Fulani way of life, which condemns excess and immoderation.

Comprehensive assessment of physiological responses in women during the ESA dry immersion VIVALDI microgravity simulation.

Astronauts in microgravity experience multi-system deconditioning, impacting their inflight efficiency and inducing dysfunctions upon return to Earth gravity. To fill the sex gap of knowledge in the health impact of spaceflights, we simulate microgravity with a 5-day dry immersion in 18 healthy women (ClinicalTrials.gov Identifier: NCT05043974). Here we show that dry immersion rapidly induces a sedentarily-like metabolism shift mimicking the beginning of a metabolic syndrome with a drop in glucose tolerance, an increase in the atherogenic index of plasma, and an impaired lipid profile. Bone remodeling markers suggest a decreased bone formation coupled with an increased bone resorption. Fluid shifts and muscular unloading participate to a marked cardiovascular and sensorimotor deconditioning with decreased orthostatic tolerance, aerobic capacity, and postural balance. Collected datasets provide a comprehensive multi-systemic assessment of dry immersion effects in women and pave the way for future sex-based evaluations of countermeasures.

New frontiers in the measurement of energy metabolism.

This perspective highlights three key areas of current and future energy metabolism research: intergenerational health, climate change, and interplanetary exploration. We describe the recent advances in determining estimated energy requirements for a large subset of the general population using the gold standard method for free-living total daily energy expenditure estimates, the doubly labeled water method. The global rise in overweight and obesity demands particular attention to energy requirements in pregnancy and early life, as accumulating evidence contributes to our understanding of intergenerational health transmission and the potential for epigenetic programming in utero. We also acknowledge some gaps in necessary guidelines and understandings of energy requirements for underrepresented populations (i.e., individuals from low and middle-income countries) or those who undergo major physiological changes in new environment (e.g., astronauts). The rising prevalence of excess weight gain, together with climate change, cumulate into a global syndemic exposing vulnerable populations to both malnutrition and the effects of unpredictable and severe weather events, emphasizing the need for varied energetic data accounting for rapid physiological and socioeconomic changes. Finally, we relate how specific estimated energy requirements are needed to account for the energetic challenges specific to extended space travel and ensure the success of interplanetary exploration.

Physiology of sedentary behavior.

Sedentary behaviors (SB) are characterized by low energy expenditure while in a sitting or reclining posture. Evidence relevant to understanding the physiology of SB can be derived from studies employing several experimental models: bed rest, immobilization, reduced step count, and reducing/interrupting prolonged SB. We examine the relevant physiological evidence relating to body weight and energy balance, intermediary metabolism, cardiovascular and respiratory systems, the musculoskeletal system, the central nervous system, and immunity and inflammatory responses. Excessive and prolonged SB can lead to insulin resistance, vascular dysfunction, shift in substrate use toward carbohydrate oxidation, shift in muscle fiber from oxidative to glycolytic type, reduced cardiorespiratory fitness, loss of muscle mass and strength and bone mass, and increased total body fat mass and visceral fat depot, blood lipid concentrations, and inflammation. Despite marked differences across individual studies, longer term interventions aimed at reducing/interrupting SB have resulted in small, albeit marginally clinically meaningful, benefits on body weight, waist circumference, percent body fat, fasting glucose, insulin, HbA1c and HDL concentrations, systolic blood pressure, and vascular function in adults and older adults. There is more limited evidence for other health-related outcomes and physiological systems and for children and adolescents. Future research should focus on the investigation of molecular and cellular mechanisms underpinning adaptations to increasing and reducing/interrupting SB and the necessary changes in SB and physical activity to impact physiological systems and overall health in diverse population groups.

Development and Initial Validation of a Measure to Assess Self-Efficacy to Reduce Sedentary Behavior.

INTRODUCTION: The purpose of this study was to assess the reliability and construct validity of a measure designed to evaluate self-efficacy to reduce sedentary behavior (SB). METHODS: Initial instrument development was based on semistructured interviews and in-depth review of existing measures of self-efficacy for physical activity (PA). Items were drafted by the study authors and reviewed by SB experts. Participants recruited via Amazon Mechanical Turk completed the pool of items and the Exercise Confidence Survey and provided self-reported PA, SB, and demographic information. The sample was divided into two random halves, and exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed on each half, respectively. Internal consistency reliability (Cronbach's alpha) was calculated for the final scale. Initial criterion validity was examined in relation to self-reported SB and PA. Analyses were conducted in SAS 9.4 and Mplus 8.3. RESULTS: Data were collected from N = 818 adults (47.6% women, mean (standard deviation) age, 37.8 (10.6)). EFA results strongly supported a one-factor scale. Items with low factor loadings (<0.65) were dropped from the scale; 10 items were retained. CFA demonstrated that the 10-item measure fit the data well, but one item had a low factor loading. A final scale with nine items was retained, with good fit to the data ( χ2 (27) = 90.79, P < 0.0001, comparative fit statistic = 0.97, root mean square error of approximation = 0.08 [90% confidence interval, 0.06-0.09], standardized root mean square residual = 0.03), and all items had high factor loadings (>0.70). Internal consistency reliability was high ( α = 0.91). Self-efficacy to reduce SB was significantly and positively correlated with exercise confidence ( r = 0.32-0.38, P < 0.0001). CONCLUSIONS: We developed a nine-item measure of self-efficacy to reduce SB that demonstrates strong initial psychometric properties. Although related to exercise self-efficacy, self-efficacy to reduce SB represents a distinct construct.

The role of physical activity in the regulation of body weight: The overlooked contribution of light physical activity and sedentary behaviors.

The role of physical activity (PA) in the regulation of body weight is still a major topic of debate. This may be because studies have essentially focused on the effects of moderate/vigorous PA (MVPA) on body weight while overlooking the other components of PA, namely, light-intensity PA (LPA, daily life activities) and sedentary behaviors (SB, too much sitting). In this review, we will (i) describe the history of changes in PA behaviors that occurred with modernization; (ii) review data from cross-sectional and longitudinal studies that examined the associations between PA, SB, and measures of obesity; (iii) review interventional studies that investigated the effects of changes in PA and SB on body weight and adiposity; and (iv) discuss experimental studies that addressed potential biological mechanisms underlying the effects of PA and SB on weight regulation. Overall recent findings support the importance of considering all components of PA to better understand the regulation of energy balance and suggest an important role for LPA and SB in addition to MVPA on body weight regulation. Longitudinal large-scale rigorous studies are needed to advance our knowledge of the role of PA/SB in combating the obesity epidemic.

Sex Differences in Physical Activity Among Individuals With Type 2 Diabetes Across the Life Span: A Systematic Review and Meta-analysis.

BACKGROUND: Physical activity (PA) is a cornerstone of type 2 diabetes mellitus (T2DM) treatment. Sex differences in PA behavior or barriers/facilitators to PA among individuals with T2DM are unclear. PURPOSE: To summarize the evidence related to sex differences in participation in PA and barriers/facilitators to PA among individuals with T2DM across the life span. DATA SOURCES: Systematic searches (CRD42021254246) were conducted with Ovid MEDLINE, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED), APA PsychInfo, and SPORTDiscus. STUDY SELECTION: We included studies with assessment of PA, sedentary behaviors (SB), or barriers/facilitators to PA among individuals with T2DM by sex or gender. DATA EXTRACTION: Participant characteristics, meeting PA guidelines, participation in PA and SB, and barriers/facilitators to PA were extracted by two independent reviewers. DATA SYNTHESIS: A total of 53 articles (65,344 participants) were included in the systematic review and 21 articles in the meta-analysis. Sex differences were not observed in meeting of PA guidelines among adolescents (odds ratio 0.70 [95% CI 0.31, 1.59]), but males were more likely than females to meet PA guidelines among adults (1.65 [1.36, 2.01]) and older adults (1.63 [1.27, 2.09]). Males performed more moderate-to-vigorous PA (MVPA) than females across all age-groups. Common barriers to PA were lack of time (men) and lack of social support and motivation (women). LIMITATIONS: Limitations include heterogeneity of measures used to assess PA and lack of stratification of data by sex. CONCLUSIONS: Sex differences in meeting PA guidelines were not observed among adolescents but were apparent among adults and older adults with T2DM. Females consistently engaged in less MVPA than males across the life span.

Effect of Exercise on Energy Expenditure and Body Composition in Astronauts Onboard the International Space Station: Considerations for Interplanetary Travel.

OBJECTIVE: Body mass (BM) loss and body composition (BC) changes threaten astronauts' health and mission success. However, the energetic contribution of the exercise countermeasure to these changes has never been investigated during long-term missions. We studied energy balance and BC in astronauts during 6-month missions onboard the International Space Station. METHODS: Before and after at least 3 months in space, BM, BC, total and activity energy expenditure (TEE and AEE) were measured using the doubly labeled water method in 11 astronauts (2011-2017). Physical activity (PA) was assessed by the SensewearPro® activity-device. RESULTS: Three-month spaceflight decreased BM (- 1.20 kg [SE 0.5]; P = 0.04), mainly due to non-significant fat-free mass loss (FFM; - 0.94 kg [0.59]). The decrease in walking time (- 63.2 min/day [11.5]; P < 0.001) from preflight was compensated by increases in non-ambulatory activities (+ 64.8 min/day [18.8]; P < 0.01). Average TEE was unaffected but a large interindividual variability was noted. Astronauts were stratified into those who maintained (stable_TEE; n = 6) and those who decreased (decreased_TEE; n = 5) TEE and AEE compared to preflight data. Although both groups lost similar BM, FFM was maintained and FM reduced in stable_TEE astronauts, while FFM decreased and FM increased in decreased_TEE astronauts (estimated between-group-difference (EGD) in ΔFFMindex [FFMI] 0.87 kg/m2, 95% CI + 0.32 to + 1.41; P = 0.01, ΔFMindex [FMI] - 1.09 kg/m2, 95% CI - 2.06 to - 0.11 kg/m2; P = 0.03). The stable_TEE group had higher baseline FFMI, and greater baseline and inflight vigorous PA than the decreased_TEE group (P < 0.05 for all). ΔFMI and ΔFFMI were respectively negatively and positively associated with both ΔTEE and ΔAEE. CONCLUSION: Both ground fitness and inflight overall PA are associated with spaceflight-induced TEE and BC changes and thus energy requirements. New instruments are needed to measure real-time individual changes in inflight energy balance components.

Metabolic profile in women differs between high versus low energy spenders during a low intensity exercise on a cycle-desk.

Active-desks are emerging strategies aiming at reducing sedentary time while working. A large inter-individual variability in energy expenditure (EE) profile has been identified and has to be explored to better optimize and individualize those strategies. Thus the present study aimed at comparing the metabolic and physical profile of individuals characterized as high spenders (H-Spenders) versus low spenders (L-Spenders) based on EE during a cycle-desk low intensity exercise. 28 healthy women working in administrative positions were enrolled. Anthropometric, body composition and fasting metabolic profile parameters were assessed. EE was determined by indirect calorimetry, at rest and during a 30-min cycle-desk use. Participants were categorized as H-Spenders and L-Spenders using the median of the difference between EE at rest and during the 30-min exercise. H-Spenders had higher mean EE (p < 0.001) and carbohydrate oxidation (p = 0.009) during exercise. H-Spenders displayed higher values for fasting plasma insulin (p = 0.002) and HOMA-IR (p = 0.002) and lower values for HDL-cholesterol (p = 0.014) than L-Spenders. The percentage of body fat mass was significantly higher in H-Spenders (p = 0.034). Individuals expending more energy during a low intensity cycling exercise presented a less healthy metabolic profile compared with L-Spenders. Future studies will have to explore whether the chronic use of cycle-desks during work time can improve energy profile regarding metabolic parameters.

A 12-Week Cycling Workstation Intervention Improves Cardiometabolic Risk Factors in Healthy Inactive Office Workers.

OBJECTIVES: The aim of this study was to evaluate the effects of a portable pedal machine intervention (60 minutes per working day) for 12 weeks on healthy tertiary employees' cardiometabolic risk factors. METHODS: Anthropometric parameters, body composition, cardiometabolic/inflammatory markers, physical fitness, physical activity, and sedentary time measured before and after the intervention were compared between office healthy workers who used a portable pedal machine (INT, n = 17) and those who did not (CTRL, n = 15). RESULTS: The INT group improved Δultrasensitive C-reactive protein ( P = 0.008), Δtotal cholesterol ( P = 0.028), and Δlight-density lipoprotein cholesterol ( P = 0.048) compared with the CTRL group (Δ: T1-T0). The intervention reduced daily sitting time ( P ≤ 0.01) and increased time spent at light intensity ( P ≤ 0.01) and moderate-to-vigorous ( P ≤ 0.01) physical activity compared with baseline values. CONCLUSIONS: These findings suggest that promoting physical activity during workdays can reduce the negative health effects of spending too much time sitting and inactive.

Short-Term Adaptations in Skeletal Muscle Mitochondrial Oxidative Capacity and Metabolic Pathways to Breaking up Sedentary Behaviors in Overweight or Obese Adults.

Breaking up sedentary behavior with short-frequent bouts of physical activity (PA) differentially influences metabolic health compared with the performance of a single-continuous bout of PA matched for total active time. However, the underlying mechanisms are unknown. We compared skeletal muscle mitochondrial respiration (high-resolution respirometry) and molecular adaptations (RNA sequencing) following 4-day exposure to breaks vs. energy-matched single-continuous PA bout in inactive adults with overweight/obesity. Participants (9M/10F, 32.2 ± 6.4 years, 30.3 ± 3.0 kg/m2) completed three 4-day interventions of a randomized cross-over study: SED, sedentary control; MICRO, 5 min brisk walking each hour for 9 h; ONE: 45 min/d continuous brisk walking bout. Fasted muscle biopsies were collected on day 5. Mitochondrial coupling in the presence of lipid-associated substrates was higher after ONE (4.8 ± 2.5) compared to MICRO (3.1 ± 1.1, p = 0.02) and SED (2.3 ± 1.0, p = 0.001). Respiratory rates did not differ across groups with carbohydrate-associated substrates. In pathways associated with muscle contraction transcription signaling, ONE and MICRO similarly enhanced Oxidative Phosphorylation and Sirtuin Signaling expression (p < 0.0001, for both). However, ONE (p < 0.001, for all), but not MICRO, had greater pathway enrichment, including Ca++, mTOR, AMPK, and HIF1α signaling, than SED. Although breaking up sedentary behavior triggered skeletal muscle molecular adaptations favoring oxidative capacity, it did not improve mitochondrial function over the short term.

Physiology of physical inactivity, sedentary behaviours and non-exercise activity: insights from the space bedrest model.

Physical inactivity, i.e. not reaching the recommended level of physical activity (PA), and sedentary behaviours (SB), i.e. sitting time, have been associated with increased risk for common metabolic diseases. Recent epidemiological data suggest that high volumes of SB are detrimental to metabolic health, even in the presence of regular exercise, i.e. moderate/vigorous PA. This suggests that the health effects of SB are independent from those of exercise. However, experimentally testing this hypothesis is complicated because of the difficulty in disassociating SB from PA. Bedrest studies, a traditional space science model, can offer new insights. In some bedrest studies, an exercise training protocol has been used to counteract the harmful effects of inactivity. While bedrest induces an inactive and sedentary state, exercise with bedrest represents a unique model of sedentary yet physically active people. Here, we review bedrest studies with and without exercise training. Although exercise training prevents the loss of muscle mass and function, even large volumes of exercise are not sufficient to fully counteract the negative metabolic adaptations triggered by inactivity. This observation supports the existence of independent adverse health effects of SB, but also the potential benefits of non-exercise activity, i.e. daily living light PA. We gathered available data to examine the complex relationships between exercise, non-exercise activity, SB and health outcomes. Given the large amount of SB in modern societies, the sole promotion of exercise, i.e. moderate/vigorous PA may be insufficient, and promotion of light PA may be a complimentary approach to improve health.

Is muscle and protein loss relevant in long-term fasting in healthy men? A prospective trial on physiological adaptations.

BACKGROUND: Fasting is attracting an increasing interest as a potential strategy for managing diseases, including metabolic disorders and complementary cancer therapy. Despite concerns of clinicians regarding protein catabolism and muscle loss, evidence-based clinical data in response to long-term fasting in healthy humans are scarce. The objective of this study was to measure clinical constants, metabolic, and muscular response in healthy men during and after a 10 day fast combined with a physical activity programme. METHODS: Sixteen men (44 ± 14 years; 26.2 ± 0.9 kg/m2 ) fasted with a supplement of 200-250 kcal/day and up to 3 h daily low-intensity physical activity according to the peer-reviewed Buchinger Wilhelmi protocol. Changes in body weight (BW) and composition, basal metabolic rate (BMR), physical activity, muscle strength and function, protein utilization, inflammatory, and metabolic status were assessed during the 10 day fast, the 4 days of food reintroduction, and at 3 month follow-up. RESULTS: The 10 day fast decreased BW by 7% (-5.9 ± 0.2 kg, P < 0.001) and BMR by 12% (P < 0.01). Fat mass and lean soft tissues (LST) accounted for about 40% and 60% of weight loss, respectively, -2.3 ± 0.18 kg and -3.53 ± 0.13 kg, P < 0.001. LST loss was explained by the reduction in extracellular water (44%), muscle and liver glycogen and associated water (14%), and metabolic active lean tissue (42%). Plasma 3-methyl-histidine increased until Day 5 of fasting and then decreased, suggesting that protein sparing might follow early proteolysis. Daily steps count increased by 60% (P < 0.001) during the fasting period. Strength was maintained in non-weight-bearing muscles and increased in weight-bearing muscles (+33%, P < 0.001). Glycaemia, insulinemia, blood lipids, and blood pressure dropped during the fast (P < 0.05 for all), while non-esterified fatty acids and urinary beta-hydroxybutyrate increased (P < 0.01 for both). After a transient reduction, inflammatory cytokines returned to baseline at Day 10 of fasting, and LST were still lower than baseline values (-2.3% and -3.2%, respectively; P < 0.05 for both). CONCLUSIONS: A 10 day fast appears safe in healthy humans. Protein loss occurs in early fast but decreases as ketogenesis increases. Fasting combined with physical activity does not negatively impact muscle function. Future studies will need to confirm these first findings.

The good life in rural and urban Senegal: A qualitative and quantitative study.

Very few studies have analyzed the influence of the environment, rural or urban, on the notion of good life and subjective well-being in sub-Saharan Africa and none, to our knowledge, has combined qualitative and quantitative methodologies for this purpose. The objectives of this interdisciplinary study were: a) to understand the emic representations of the good life in rural and urban Senegal and; b) to compare the levels and determinants of satisfaction with life between these two populations. This study was carried out in Dakar and in a very isolated rural area in the North East of Senegal: the sylvo-pastoral zone of Ferlo. A total of six focus groups were conducted for the qualitative phase, while the quantitative phase was conducted on representative samples of the populations living in Dakar (N = 1000) and Téssékéré (N = 500). Our results indicate that, against all expectations, life satisfaction is better in the Senegalese Ferlo than in the capital, Dakar. This difference may be the joint result of less meaningful social comparisons and a relationship with nature as a source of stress restoration in rural areas. However, the lifeworld of the rural Fulani of the Ferlo is being undermined by global climatic disturbances, which imposes rapid adaptations of pastoralism; otherwise this activity, that is not only subsistence but also identity-based, may disappear.

Acute effects of sedentary breaks on vascular health in adults at risk for type 2 diabetes: A systematic review.

The aim of this systematic review was to evaluate the available evidence regarding the acute effects of interrupting/breaking up prolonged sedentary behavior (SB) on vascular health among individuals at elevated risk for type 2 diabetes (T2D). Searches of MEDLINE, Embase, Web of Science, and Cochrane Library databases were conducted on April 7, 2020. Included studies: (1) examined the effect of breaking up prolonged SB in adults with or at elevated risk for T2D and (2) assessed a vascular health outcome, such as blood pressure (BP), flow-mediated dilation (FMD), pulse-wave velocity, or endothelin-1. A total of 20 articles (17 unique studies) were included. Only three studies reported adequate statistical power for the specified vascular outcome. The available evidence suggests that light and moderate intensity activity breaks are effective in acutely lowering BP when compared to prolonged sitting. The small number of studies that included FMD or other vascular outcomes prohibits conclusions regarding the impact of SB breaks on these outcomes. Few studies evaluating the impact of breaking up SB among adults at risk for T2D have included and been adequately powered to examine vascular outcomes, but our preliminary finding, that certain SB breaks improve BP, provides proof-of-concept for this line of inquiry. Future studies should examine both the acute and chronic vascular effects of breaking up SB among individuals most vulnerable to the effects of SB (e.g. older adults, those with T2D), as these individuals are both highly sedentary and at greatest risk of poor health outcomes. PROSPERO ID: CRD42020183423.

Effects of cycling workstation to get tertiary employee moving on their overall health: study protocol for a REMOVE trial.

BACKGROUND: Sedentary behaviour (SB) and low levels of physical activity (PA) are predictors of morbidity and mortality. Tertiary employees spend a considerable amount of their daily time seated and new efficient strategies to both reduce sedentary time and increase physical activity are needed. In that context, the REMOVE study aims at evaluating the health effects of a 24-week cycling desk intervention among office workers. METHODS: A prospective, open-label, multicentre, two-arm parallel, randomized controlled trial (RCT) will be conducted in office-sitting desk workers. Office workers (N = 80) who have 0.8 full time equivalent hours (FTE) and 75% of this time in a sitting position will be recruited from tertiary worksites in Clermont-Ferrand, France. Subjects will be randomly assigned to one of the two following interventions: (i) PPM6: performance of two 30 min of cycling desk (using portable pedal exercise machine-PPM) per working day for 6 months or (ii) CTL_PPM3: 3 months with no intervention (control) followed by 3 months during which workers will be asked to complete two 30 min of PPM per working day. At baseline (T0), at 3 months (T1) and at 6 months (T2) after the start of the interventions, primary outcomes; 7-day PA and SB (3D-accelerometers), secondary outcomes; body composition (bioelectrical impedance), physical fitness (aerobic fitness, upper and lower limb strength), metabolic outcomes (fasting blood samples), self-perceived stress, anxiety, quality of life at work and job strain (questionnaires), tertiary outcomes; resting metabolic rate and cycling energy expenditure (indirect calorimetry) and eating behaviours (questionnaires) will be measured. An ergonomic approach based on observations and individual interviews will be used to identify parameters that could determine adherence. DISCUSSION: The REMOVE study will be the first RCT to assess the effects of cycling workstations on objectively measured PA and SB during working and non-working hours and on key physiological and psychological health outcomes. This study will provide important information regarding the implementation of such cycling workstations in office workers and on the associated potential health benefits. TRIAL REGISTRATION: ClinicalTrials.gov NCT04153214 . Registered on November 2019, version 1.