Acute effects of exercise on appetite, food intake and circulating concentrations of gastrointestinal hormones

Recent years have witnessed significant research into the acute effects of exercise on appetite, energy intake and gut hormone responses. The experiments in this thesis have further investigated this topic by examining the appetite, acylated ghrelin, peptide YY and energy intake responses to energy deficits induced via different exercise protocols and food restriction. To achieve this, 48 young healthy males (mean (SD): age 23 (3) years, body mass index 23.7 (2.7) kg.m-2, maximum oxygen uptake 52.9 (9.8) mL.kg 1.min-1) were recruited into four studies. In study one, 60 min of treadmill running at 70% of VO2 max did not stimulate any increases in appetite or daily energy intake regardless of whether the exercise was performed after breakfast or in the fasted state. In study two, six 30 s Wingate tests stimulated increases in appetite during the subsequent hours compared with 60 min of cycling at 68% of VO2 max. Differences in appetite appeared to be unrelated to changes in plasma acylated ghrelin concentrations and did not influence ad libitum energy intake. Subsequently, endurance exercise resulted in a significantly greater negative daily energy balance than sprint exercise due to a larger exercise energy expenditure. Study three revealed that appetite and energy intake did not differ from a resting control trial after either ten, 4 min cycling bouts at 85 90% of VO2 max separated by 2 min of rest or 60 min of constant cycling at 60% of VO2 max. This occurred despite elevated PYY3-36 concentrations during the hours after exercise. Finally, study four showed that an energy deficit of ~1475 kJ stimulated increases in appetite when induced via food restriction but not when achieved by an acute bout of exercise. This was associated with differences in plasma PYY3-36 concentrations but did not appear to be related to changes in circulating levels of acylated ghrelin and did not influence energy intake. This thesis has shown that appetite perceptions do not differ from a resting control trial during the hours after continuous endurance exercise. Alternatively, supramaximal cycling exercise and subtle reductions in food intake stimulated increases in appetite during the subsequent hours. Such increases in appetite do not appear to be related to changes in acylated ghrelin but may be influenced by plasma PYY3-36 concentrations. Despite differences in appetite, daily energy intake was unaffected by all interventions

Appetite and energy intake responses to acute energy deficits in females versus males

PURPOSE: To explore whether compensatory responses to acute energy deficits induced by exercise or diet differ by sex. METHODS: In experiment one, twelve healthy women completed three 9 h trials (control, exercise-induced (Ex-Def) and food restriction induced energy deficit (Food-Def)) with identical energy deficits being imposed in the Ex-Def (90 min run, ∼70% of VO2 max) and Food-Def trials. In experiment two, 10 men and 10 women completed two 7 h trials (control and exercise). Sixty min of running (∼70% of VO2 max) was performed at the beginning of the exercise trial. Participants rested throughout the remainder of the exercise trial and during the control trial. Appetite ratings, plasma concentrations of gut hormones and ad libitum energy intake were assessed during main trials. RESULTS: In experiment one, an energy deficit of ∼3500 kJ induced via food restriction increased appetite and food intake. These changes corresponded with heightened concentrations of plasma acylated ghrelin and lower peptide YY3-36. None of these compensatory responses were apparent when an equivalent energy deficit was induced by exercise. In experiment two, appetite ratings and plasma acylated ghrelin concentrations were lower in exercise than control but energy intake did not differ between trials. The appetite, acylated ghrelin and energy intake response to exercise did not differ between men and women. CONCLUSIONS: Women exhibit compensatory appetite, gut hormone and food intake responses to acute energy restriction but not in response to an acute bout of exercise. Additionally, men and women appear to exhibit similar acylated ghrelin and PYY3-36 responses to exercise-induced energy deficits. These findings advance understanding regarding the interaction between exercise and energy homeostasis in women

The effect of prior walking on coronary heart disease risk markers in South Asian and European men

Purpose: Heart disease risk is elevated in South Asians possibly due to impaired postprandial metabolism. Running has been shown to induce greater reductions in postprandial lipaemia in South Asian than European men but the effect of walking in South Asians is unknown. Methods: Fifteen South Asian and 14 White European men aged 19-30 years completed two, 2-d trials in a randomised crossover design. On day 1, participants rested (control) or walked for 60 min at approximately 50% maximum oxygen uptake (exercise). On day 2, participants rested and consumed two high fat meals over a 9h period during which 14 venous blood samples were collected. Results: South Asians exhibited higher postprandial triacylglycerol (geometric mean (95% confidence interval) 2.29(1.82 to 2.89) vs. 1.54(1.21 to 1.96) mmol·L-1·hr-1), glucose (5.49(5.21 to 5.79) vs. 5.05(4.78 to 5.33) mmol·L-1·hr-1), insulin (32.9(25.7 to 42.1) vs. 18.3(14.2 to 23.7) μU·mL-1·hr-1) and interleukin-6 (2.44(1.61 to 3.67) vs. 1.04(0.68 to 1.59) pg·mL-1·hr-1) than Europeans (all ES ≥ 0.72, P≤0.03). Between-group differences in triacylglycerol, glucose and insulin were not significant after controlling for age and percentage body fat. Walking reduced postprandial triacylglycerol (1.79(1.52 to 2.12) vs. 1.97(1.67 to 2.33) mmol·L-1·hr-1) and insulin (21.0(17.0 to 26.0) vs. 28.7(23.2 to 35.4) μU·mL-1·hr-1) (all ES ≥ 0.23. P≤0.01), but group differences were not significant. Conclusions: Healthy South Asians exhibited impaired postprandial metabolism compared with White Europeans, but these differences were diminished after controlling for potential confounders. The small-moderate reduction in postprandial triacylglycerol and insulin after brisk walking was not different between the ethnicities

Individual variation in hunger, energy intake and ghrelin responses to acute exercise

Purpose: To characterise the immediate and extended impact of acute exercise on hunger, energy intake and circulating acylated ghrelin concentrations using a large dataset of homogenous experimental trials; and to describe the variation in responses between individuals. Methods: Data from 17 of our group’s experimental crossover trials were aggregated yielding a total sample of 192 young, healthy, males. In these studies, single bouts of moderate to high-intensity aerobic exercise (69 ± 5% VO2 peak; mean ± SD) were completed with detailed participant assessments occurring during and for several hours post-exercise. Mean hunger ratings were determined during (n = 178) and after (n = 118) exercise from visual analogue scales completed at 30 min intervals whilst ad libitum energy intake was measured within the first hour after exercise (n = 60) and at multiple meals (n = 128) during the remainder of trials. Venous concentrations of acylated ghrelin were determined at strategic time points during (n = 118) and after (n = 89) exercise. Results: At group-level, exercise transiently suppressed hunger (P < 0.010; Cohen’s d = 0.77) but did not affect energy intake. Acylated ghrelin was suppressed during exercise (P < 0.001; Cohen’s d = 0.10) and remained significantly lower than control (no exercise) afterwards (P < 0.024; Cohen’s d = 0.61). Between participants, there were notable differences in responses however a large proportion of this spread lay within the boundaries of normal variation associated with biological and technical assessment error. Conclusion: In young men, acute exercise suppresses hunger and circulating acylated ghrelin concentrations with notable diversity between individuals. Care must be taken to distinguish true inter-individual variation from random differences within normal limits

Analytical performance of the factory-calibrated flash glucose monitoring system FreeStyle Libre2^TM in healthy women

Continuous glucose monitoring (CGM) is used clinically and for research purposes to capture glycaemic profiles. The accuracy of CGM among healthy populations has not been widely assessed. This study assessed agreement between glucose concentrations obtained from venous plasma and from CGM (FreeStyle Libre2TM, Abbott Diabetes Care, Witney, UK) in healthy women. Glucose concentrations were assessed after fasting and every 15 min after a standardized breakfast over a 4-h lab period. Accuracy of CGM was determined by Bland–Altman plot, 15/15% sensor agreement analysis, Clarke error grid analysis (EGA) and mean absolute relative difference (MARD). In all, 429 valid CGM readings with paired venous plasma glucose (VPG) values were obtained from 29 healthy women. Mean CGM readings were 1.14 mmol/L (95% CI: 0.97 to 1.30 mmol/L, p TM CGM system tends to overestimate glucose concentrations compared to venous plasma samples in healthy women, especially during hypoglycaemia and during glycaemic swings.</p

Analytical Performance of the Factory-Calibrated Flash Glucose Monitoring System FreeStyle Libre2TM in Healthy Women

Continuous glucose monitoring (CGM) is used clinically and for research purposes to capture glycaemic profiles. The accuracy of CGM among healthy populations has not been widely assessed. This study assessed agreement between glucose concentrations obtained from venous plasma and from CGM (FreeStyle Libre2TM, Abbott Diabetes Care, Witney, UK) in healthy women. Glucose concentrations were assessed after fasting and every 15 min after a standardized breakfast over a 4-h lab period. Accuracy of CGM was determined by Bland–Altman plot, 15/15% sensor agreement analysis, Clarke error grid analysis (EGA) and mean absolute relative difference (MARD). In all, 429 valid CGM readings with paired venous plasma glucose (VPG) values were obtained from 29 healthy women. Mean CGM readings were 1.14 mmol/L (95% CI: 0.97 to 1.30 mmol/L, p < 0.001) higher than VPG concentrations. Ratio 95% limits of agreement were from 0.68 to 2.20, and a proportional bias (slope: 0.22) was reported. Additionally, 45% of the CGM readings were within ±0.83 mmol/L (±15 mg/dL) or ±15% of VPG, while 85.3% were within EGA Zones A + B (clinically acceptable). MARD was 27.5% (95% CI: 20.8, 34.2%), with higher MARD values in the hypoglycaemia range and when VPG concentrations were falling. The FreeStyle Libre2TM CGM system tends to overestimate glucose concentrations compared to venous plasma samples in healthy women, especially during hypoglycaemia and during glycaemic swings

Table1_A scalable 12-week exercise and education programme reduces symptoms and improves function and wellbeing in people with hip and knee osteoarthritis.docx

IntroductionOsteoarthritis is a chronic musculoskeletal condition that impacts more than 300 million people worldwide, with 43 million people experiencing moderate to severe disability due to the disease. This service evaluation provides the results from a tailored blended model of care on joint health, physical function, and personal wellbeing.Methods1,593 adult participants with osteoarthritis completed the Nuffield Health Joint Pain Programme between February 2019 and May 2022. The 12-week programme included two 40-min exercise sessions per week. All exercise sessions were conducted face-to-face and were followed by 20 min of education to provide information and advice on managing osteoarthritis.ResultsThe 12-week joint pain programme significantly improved Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) global scores (Week 0: 37.5 [17.2]; Week 12: 24.0 [16.6]; p 2; Week 12: 28.6 [4.4] kg/m2; p DiscussionWith reductions in physical symptoms of osteoarthritis and improvements in personal wellbeing, the joint pain programme delivered by personal trainers in a gym-setting offers a nationally scalable, non-pharmacological treatment pathway for osteoarthritis.</p

Improved clinical outcomes in response to a 12-week blended digital and community-based Long-COVID-19 rehabilitation programme

Introduction: Two million people in the UK are experiencing long covid (LC), which necessitates effective and scalable interventions to manage this condition. This study provides the first results from a scalable rehabilitation programme for participants presenting with LC. Methods: 601 adult participants with symptoms of LC completed the Nuffield Health COVID-19 Rehabilitation Programme between February 2021 and March 2022 and provided written informed consent for the inclusion of outcomes data in external publications. The 12-week programme included three exercise sessions per week consisting of aerobic and strength-based exercises, and stability and mobility activities. The first six weeks of the programme were conducted remotely, whereas the second six weeks incorporated face-to-face rehabilitation sessions in a community setting. A weekly telephone call with a rehabilitation specialist was also provided to support queries and advise on exercise selection, symptom management and emotional wellbeing. Results: The 12-week rehabilitation programme significantly improved Dyspnea-12 (D-12), Duke Activity Status Index (DASI), World Health Orginaisation-5 (WHO-5) and EQ-5D-5L utility scores (all p < 0.001), with the 95% confidence intervals (CI) for the improvement in each of these outcomes exceeding the minimum clinically important difference (MCID) for each measure (mean change [CI]: D-12: -3.4 [-3.9, -2.9]; DASI: 9.2 [8.2, 10.1]; WHO-5: 20.3 [18.6, 22.0]; EQ-5D-5L utility: 0.11 [0.10, 0.13]). Significant improvements exceeding the MCID were also observed for sit-to-stand test results (4.1 [3.5, 4.6]). On completion of the rehabilitation programme, participants also reported significantly fewer GP consultations (p < 0.001), sick days (p = 0.003) and outpatient visits (p = 0.007) during the previous three months compared with baseline. Discussion: The blended and community design of this rehabilitation model makes it scalable and meets the urgent need for an effective intervention to support patients experiencing LC. This rehabilitation model is well placed to support the NHS (and other healthcare systems worldwide) in its aim of controlling the impacts of COVID-19 and delivering on its long-term plan. Trial Registration: ISRCTN Registry (ID: 14707226)

Centre of pressure total sway velocity (cm/s) for standing balance with eyes open along with altitude profile.

<p>Box plots show medians, quartiles, whiskers representing the max and min values, and dots representing individual participant values (O = positive LLS in 24 hrs before test). <b>*</b>p<0.05 vs. SL, ^<b>¶</b>Cohen’s d > 0.8 compared with sea level.</p

Centre of pressure velocity in the anterior-posterior direction at different altitudes.

<p>Centre of pressure velocity in the anterior-posterior direction at different altitudes.</p