Background: There is considerable disagreement about the association between free-living physical activity (PA) and sedentary behaviour and obesity. Moreover studies frequently do not include measures that could mediate between PA and adiposity. The present study used a validated instrument for continuous tracking of sedentary and active behaviours as part of habitual daily living, together with measures of energy expenditure, body composition and appetite dysregulation. This cross-sectional study tested the relationship between inactivity and obesity.Methods: 71 participants (81.7% women) aged 37.4 years (±14) with a body mass index of 29.9 kg/m2(±5.2) were continuously monitored for 6–7 days to track free-living PA (light 1.5–3 metabolic equivalents (METs), moderate 3–6 METs and vigorous >6 METs) and sedentary behaviour (<1.5 METs) with the SenseWear Armband. Additional measures included body composition, waist circumference, cardiovascular fitness, total and resting energy expenditure, and various health markers. Appetite control was assessed by validated eating behaviour questionnaires.Results: Sedentary behaviour (11.06±1.72 h/day) was positively correlated with fat mass (r=0.50, p<0.001) and waist circumference (r=−0.65, p<0.001). Moderate-to-vigorous PA was negatively associated with fat mass (r=−0.72, p<0.001) and remained significantly correlated with adiposity after controlling for sedentary behaviour. Activity energy expenditure was positively associated with the level of PA and negatively associated with fat mass. Disinhibition and binge eating behaviours were positively associated with fat mass (r=0.58 and 0.47, respectively, p<0.001).Conclusions: This study demonstrated clear associations among objective measures of PA (and sedentary behaviour), energy expenditure, adiposity and appetite control. The data indicate strong links between physical inactivity and obesity. This relationship is likely to be bidirectional.
Exercise-induced weight loss is often less than expected and highly variable in men and women. Behavioural compensation for the exercise-induced energy deficit could be through energy intake (EI), non-exercise physical activity (NEPA) or sedentary behaviour (SB). We investigated this issue in women. Twenty-four overweight [body mass index (BMI) M = 27.9 kg/m2, SD = 2.7] women [age M = 33.1 years, SD = 11.7] completed 12-weeks of supervised exercise (5×500kcal per week) in a non-randomised, pre-post intervention study. Body mass (BM), waist circumference (WC), body composition, resting metabolic rate (RMR), total daily EI, individual meals, appetite sensations and appetite-related peptides were measured at baseline (week 0) and post-intervention (week 12). Free-living physical activity (PA) and SB were measured (SenseWear) at baseline, week 1 and 10 of the exercise intervention, and at post-intervention (week 13). Following the 12-week exercise intervention BM [p = .04], BMI [p = .035], WC [p < .001] and fat mass (FM) [p = .003] were significantly reduced, and fat-free mass (FFM) significantly increased [p = .003]. Total [p = .028], ad libitum [p = .03] and snack box EI [p = .048] were significantly increased and this was accompanied by an increase in hunger [p = .01] and a decrease in fullness [p = .03] before meals. The peptides did not explain changes in appetite [p > .05]. There was no compensatory reduction in NEPA [p > .05] and no increase in SB, rather there was a decrease in SB during the exercise intervention [p = .03]. Twelve-weeks of supervised aerobic exercise resulted in a significant reduction in FM and an increase in FFM. Exercise increased hunger and EI which only partially compensated for the increase in energy expenditure. There was no evidence for a compensatory reduction in NEPA or an increase in SB. Dietary intervention, as an adjunct to exercise, may offset the compensatory increase in EI and result in a greater reduction in BM. Our trial was retrospectively registered on the International Standard Randomised Controlled Trials Registry (ISRCTN78021668, 27th September 2016) and can be found here: https://doi.org/10.1186/ISRCTN78021668.
18 October 2017 in Expert Review of Endocrinology & Metabolism
Introduction: Homeostatic appetite control is part of a psychobiological system that has evolved to maintain an adequate supply of nutrients for growth and maintenance. The system links the physiological needs for energy with the behaviour that satisfies these needs (feeding), and is shaped by excitatory and inhibitory signals. Owing to rapid shifts in the food environment, homeostatic appetite control is not well adapted for modern-day human functioning. Areas covered: Homeostatic appetite control has two divisions. Tonic processes exert stable and enduring influences, with signals arising from bodily tissues and metabolism. Episodic processes fluctuate rapidly and are related to nutrient ingestion and the composition of foods consumed. Research in these areas incorporates potent endocrine signals that can influence behaviour. Expert commentary: The regulation of adipose tissue, and its impact on appetite (energy) homeostasis, has been heavily researched. More recently however, it has been demonstrated that fat-free mass has the potential to act as a tonic driver of food intake. A challenging issue is to determine how the post-prandial action of episodic satiety hormones and gastrointestinal mechanisms can effectively brake the metabolic drive to eat, in order to keep food intake under control and prevent a positive energy balance and fat accumulation.
Background: Physical activity (PA) contributes to the prevention and management of many health conditions. Primary care practitioners have an important role to play in supporting people to be physically active.Aim: This study had the following three aims: 1) to explore GPs‘ awareness and knowledge of the PA guidelines; 2) to assess GPs’ confidence in promoting PA; and 3) to explore factors that influence PA promotion among GPs.Design & setting: Cross-sectional survey, using secondary analysis.Method: UK-based GPs were invited to take part in an online survey in January 2021. Demographic questions were followed by nine multiple choice questions. Categorical data were analysed using descriptive statistics, and open-ended data were analysed using content analysis and inductive coding.Results: In total, 839 GPs based in England completed the survey. Most GP responders (98.9%) believed that PA was important, yet only 35.7% reported being at least ‘somewhat familiar’ with current PA guidance. Despite this, 74.1% of GPs reported feeling confident raising the topic of PA with their patients. Barriers included lack of time, perceptions of patient attitude and risk, language issues, and COVID-19. Key facilitators were identified and ‘Couch to 5k’ and the ‘parkrun practice’ initiatives were the most widely used support tools.Conclusion: GPs value PA yet well-known barriers exist to embedding promotion into primary care. As primary care reconfigures, there is an opportunity to embed PA into systems, services, and processes.
The widely accepted definition of sedentary behaviour [SB] refers to any waking behaviour characterized by an energy expenditure ≤1.5 metabolic equivalents [METs] while in a sitting or reclining posture. At present, there is no single field-based device which objectively measures sleep, posture and activity intensity simultaneously. The aim of this study was to develop a novel integrative procedure [INT] to combine information from two validated activity monitors on sleep, activity intensity and posture, the three key dimensions of SB. Participants in this analysis were initially recruited from a series of three studies conducted between December 2014 and June 2016 at the University of Leeds. Sixty-three female participants aged 37.1 (13.6) years with a body mass index of 29.6 (4.7) kg/m2 were continuously monitored for 5–7 days with the SenseWear Armband [SWA] (sleep and activity intensity) and the activPAL [AP] (posture). Data from both activity monitors were analysed separately and integrated resulting in three measures of sedentary time. Differences in Sedentary time between the three measurement methods were assessed as well as how well the three measures correlated. The three measures of sedentary time were positively correlated, with the weakest relationship between SEDSWA (awake and <1.5 METs) and SEDAP (awake and sitting/lying posture) [r(61) = .37,p = .003], followed by SEDSWA and SEDINT (awake, <1.5 METs and sitting/lying posture) [r(61) = .58,p < .001], and the strongest relationship was between SEDAP and SEDINT [r(61) = .91,p < .001]. There was a significant difference between the three measures of sedentary time [F(1.18,73.15) = 104.70,p < .001]. Post-hoc tests revealed all three methods differed significantly from each other [p < .001]. SEDSWA resulted in the most sedentary time 11.74 (1.60) hours/day, followed by SEDAP 10.16 (1.75) hours/day, and SEDINT 9.10 (1.67) hours/day. Weekday and weekend day sedentary time did not differ for any of the measurement methods [p = .04–.25]. Information from two validated activity monitors was combined to obtain an objective measure of free-living SB based on posture and activity intensity during waking hours. The amount of sedentary time accumulated varied according to the definition of SB and its measurement. The novel data integration and processing procedures presented in this paper represents an opportunity to investigate whether different components of SB are differentially related to health end points.
In 2017 Public Health England and Sport England commissioned a Consultant-led Sport and Exercise Medicine (SEM) pilot to test the feasibility and acceptability of embedding physical activity interventions in secondary care clinical pathways. The aim of this paper is to report qualitative findings exploring the experience of healthcare professionals (HCPs) and patients involved in the Active Hospital pilot. Qualitative data was collected by semi-structured interviews with Active Hospital pilot SEM Consultants, and staff and patients involved in three clinical pathways. Interviews with SEM Consultants explored the experience of developing and implementing the pilot. Interviews with staff and patients explored the experience of delivering and receiving Active Hospital interventions. Data were analysed thematically. Interviews identified the importance of the Active Hospital pilot being Consultant-led for the following reasons; i) having trusting relationships with decision makers, ii) having sufficient influence to effect change, iii) identifying champions within the system, and iv) being adaptable to change and ensuring the programme fits within the wider strategic frameworks. HCPs emphasised the importance of the Active Hospital interventions fitting easily within existing work practices, the need for staff training and to tailor interventions for individual patient needs. The Active Hospital pilot was well received by patients, however a lack of dedicated resource and capacity to deliver the intervention was highlighted as a challenge by both patients and HCPs. The SEM Consultants’ ability to navigate the political climate of a large National Health Service (NHS) Trust with competing agendas and limited resource was valuable. The interventions were well received and a valued addition to usual clinical care. However, implementation and ongoing delivery of the pilot encountered challenges including lack of capacity within the system and delays with recruiting to the delivery teams in each pathway.