Acute effects of exercise on appetite, appetite regulatory hormones and energy intake in lean and overweight men and women

The acute effects of exercise on appetite, ad libitum energy intake and gut hormone responses have received much attention over the past two decades. The experiments in this thesis have contributed to this research by examining appetite, acylated ghrelin, peptide-YY (PYY), leptin and ad libitum energy intake responses to two consecutive days of moderate-high intensity running. To achieve this 15 individuals aged 21 (2) y, with a BMI of 23.0 (1.9) kg·m-2 were recruited. Additionally, appetite, acylated ghrelin, PYY, glucagon-like peptide-1 (GLP-1), and ad libitum energy intake responses to an acute bout of moderate intensity treadmill exercise were compared in lean and overweight/obese (ow/ob) males and females. Two separate cohorts of individuals were recruited; 22 lean individuals and 25 ow/ob individuals (aged 38 (15) and 45 (12) y, with a BMI of 22 (2) and 29 (3) kg·m 2, for lean and ow/ob individuals, respectively). In Chapter 4, two consecutive days of 60 min treadmill running at 70% V̇O2 peak did not produce compensatory changes in appetite or energy intake over two days. There were no main effects of trial for acylated ghrelin or leptin. However a main effect of trial for PYY indicated higher concentrations on the exercise than control trial. A meta-analysis was completed in Chapter 5, suggesting further research in the effects of acute exercise on appetite regulatory hormones in individuals who are ow/ob was necessary. In Chapter 6, 60 min of treadmill exercise at 60% V̇O2 peak did not alter appetite sensations or energy intake in the 7 h after exercise in lean and ow/ob males and females. There were no main effects of sex, BMI or trial for acylated ghrelin; however, PYY and GLP-1 concentrations were higher in exercise than control trials. This thesis has demonstrated that over two days, high volume exercise does not stimulate compensatory appetite regulatory changes, in lean healthy males. In the short term, lean and ow/ob males and females respond similarly to acute exercise, showing no alterations in appetite or food intake responses, whilst PYY and GLP-1 concentrations are higher in exercise than control trials

The influence of adiposity and acute exercise on circulating hepatokines in normal weight and overweight/obese men

Hepatokines are liver-secreted proteins with potential to influence glucose regulation and other metabolic parameters. This study investigated differences in adiposity status on five novel hepatokines and characterised their response to acute moderate-intensity exercise in groups of normal weight and overweight/obese men. Twenty-two men were recruited into normal weight and overweight/obese groups (BMI: 18.5 to 24.9 and 25.0 to 34.9 kg∙m-2). Each completed two experimental trials, exercise and control. During exercise trials, participants performed 60 min of moderate-intensity treadmill exercise (~60% V̇O2 peak) and then rested for 6 h. Participants rested throughout control trials. Circulating fibroblast growth factor-21 (FGF21), follistatin, leukocyte cell-derived chemotaxin 2 (LECT2), fetuin-A and selenoprotein-P (SeP) were measured throughout. Fasted (resting) FGF21 and LECT2 were higher in overweight/obese individuals (129% and 55%; P ≤ 0.01) and correlated with indices of adiposity and insulin resistance; whereas circulating follistatin was lower in overweight/obese individuals throughout trial days (17%, P < 0.05). In both groups, circulating concentrations of FGF21 and follistatin were transiently elevated after exercise for up to 6 h (P ≤ 0.02). Circulating fetuin-A and SeP were no different between groups (P ≥ 0.19) and, along with LECT2, were unaffected by exercise (P ≥ 0.06). These findings show that increased adiposity is associated with a modified hepatokine profile, which may represent a novel mechanism linking excess adiposity to metabolic health. Furthermore, acute perturbations in circulating FGF21 and follistatin after exercise may contribute to the health benefits of an active lifestyle

Acute effects of exercise on appetite, ad libitum energy intake and appetite-regulatory hormones in lean and overweight/obese men and women

BACKGROUND: Acute exercise does not elicit compensatory changes in appetite parameters in lean individuals; however, less is known about responses in overweight individuals. This study compared the acute effects of moderate-intensity exercise on appetite, energy intake and appetite-regulatory hormones in lean and overweight/obese individuals. METHODS: Forty-seven healthy lean (n=22, 11 females; mean(s.d.) 37.5(15.2) years; 22.4(1.5) kg·m−2) and overweight/obese (n=25, 11 females; 45.0(12.4) years, 29.2(2.9) kg·m−2) individuals completed two, 8-h trials (exercise and control). In the exercise trial, participants completed 60 min treadmill exercise (59(4)% peak oxygen uptake) at 0–1 h and rested thereafter whilst participants rested throughout the control trial. Appetite ratings and concentrations of acylated ghrelin, peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) were measured at pre-determined intervals. Standardised meals were consumed at 1.5 and 4 h and an ad libitum buffet meal was provided at 7 h. RESULTS: Exercise suppressed appetite (95% CI −3.1 to −0.5 mm, P=0.01), and elevated delta PYY (95% CI 10 to 17 pg·ml−1, P<0.001) and GLP-1 (95% CI 7 to 10 pmol·l−1, P<0.001) concentrations. Delta acylated ghrelin concentrations (95% CI −4.6 to 3.4 pg·ml−1, P=0.76) and ad libitum energy intake (95% CI −391 to 346 kJ, P=0.90) were similar between trials. Subjective and hormonal appetite parameters and ad libitum energy intake were similar between lean and overweight/obese individuals (Pgreater than or equal to0.27). The exercise-induced elevation in delta GLP-1 was greater in overweight/obese individuals (trial-by-group interaction P=0.01), whereas lean individuals exhibited a greater exercise-induced increase in delta PYY (trial-by-group interaction P<0.001). CONCLUSIONS: Acute moderate-intensity exercise transiently suppressed appetite and increased PYY and GLP-1 in the hours after exercise without stimulating compensatory changes in appetite in lean or overweight/obese individuals. These findings underscore the ability of exercise to induce a short-term energy deficit without any compensatory effects on appetite regardless of weight status