The influence of vigorous running and cycling exercise on hunger perceptions and plasma acylated ghrelin concentrations in lean young men
ABSTRACT Vigorous running suppresses plasma acylated ghrelin concentrations but the limited literature on cycling suggests that acylated ghrelin is unchanged, perhaps because body mass is supported during cycling. It is important from a research and applied perspective to determine whether acylated ghrelin and hunger responses are exercise-mode specific. This study sought to examine this. Eleven recreationally active males fasted overnight and completed three 4-h trials: control, running, and cycling, in a random order. Participants rested throughout the control trial and ran or cycled at 70% of mode-specific maximal oxygen uptake for the first hour during exercise trials, resting thereafter. Hunger was measured every 0.5 h using visual analogue scales. Eight venous blood samples were collected to determine acylated ghrelin concentrations and a standardised meal was consumed at 3 h. Compared with the control trial, acylated ghrelin concentrations were suppressed to a similar extent at 0.5 and 1 h during the running (p < 0.005) and cycling (p < 0.001) trials. Area under the curve values for ghrelin concentration over time were lower during exercise trials versus control (Control: 606 ± 379; Running: 455 ± 356; Cycling: 448 ± 315 pg·mL(-1)·4 h(-1); mean ± SD, p < 0.05). Hunger values did not differ significantly between trials but an interaction effect (p < 0.05) indicated a tendency for hunger to be suppressed during exercise. Thus, at similar relative exercise intensities, plasma acylated ghrelin concentrations are suppressed to a similar extent during running and cycling.
SourceAvailable from: Melinda M Manore[Show abstract] [Hide abstract]
ABSTRACT: The regulation of appetite and energy intake is influenced by numerous hormonal and neural signals, including feedback from changes in diet and exercise. Exercise can suppress subjective appetite ratings, subsequent energy intake, and alter appetite-regulating hormones, including ghrelin, peptide YY, and glucagon-like peptide 1(GLP-1) for a period of time post-exercise. Discrepancies in the degree of appetite suppression with exercise may be dependent on subject characteristics (e.g., body fatness, fitness level, age or sex) and exercise duration, intensity, type and mode. Following an acute bout of exercise, exercise-trained males experience appetite suppression, while data in exercise-trained women are limited and equivocal. Diet can also impact appetite, with low-energy dense diets eliciting a greater sense of fullness at a lower energy intake. To date, little research has examined the combined interaction of exercise and diet on appetite and energy intake. This review focuses on exercise-trained men and women and examines the impact of exercise on hormonal regulation of appetite, post-exercise energy intake, and subjective and objective measurements of appetite. The impact that low-energy dense diets have on appetite and energy intake are also addressed. Finally, the combined effects of high-intensity exercise and low-energy dense diets are examined. This research is in exercise-trained women who are often concerned with weight and body image issues and consume low-energy dense foods to keep energy intakes low. Unfortunately, these low-energy intakes can have negative health consequences when combined with high-levels of exercise. More research is needed examining the combined effect of diet and exercise on appetite regulation in fit, exercise-trained individuals.Nutrients 11/2014; 6(11):4935-4960. DOI:10.3390/nu6114935 · 3.15 Impact Factor
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ABSTRACT: Abstract This study investigated the effect of hypohydration produced by exercise and sub-optimal rehydration on appetite and energy intake. Ten males lost ~2% body mass through evening exercise in the heat (35°C). Over the next 13 h, participants were re-fed and either rehydrated (RE: water equal to 175% of body mass loss (BML)) or remained hypohydrated (HYPO: 200 ml water), until the following morning. Urine samples, blood samples and subjective feelings were collected pre-exercise, post-exercise and 13 h post-exercise, with an ad libitum breakfast provided 13 h post-exercise. Total BML at 13 h post-exercise was greater during HYPO (2.8 (0.5)%) than RE (0.5 (0.5)%). Energy intake at the ad libitum breakfast was similar between trials (RE: 4237 (1459) kJ; HYPO: 4612 (1487) kJ; P = 0.436), with no difference in energy consumed in foods (P = 0.600) or drinks (P = 0.147). Total water ingestion at the ad libitum breakfast meal was greater during HYPO (1641 (367) ml) than RE (797 (275) ml) (P < 0.001), with this being explained by increased water intake through fluids (P < 0.001). Thirteen hours post-exercise, participants reported greater thirst (P < 0.001) and lower fullness (P < 0.01) during HYPO. Alterations in hydration status produced by exercise are unlikely to influence post-exercise food intake and consequently other aspects of recovery or adaptation.Journal of Sports Sciences 12/2014; 33(8):1-8. DOI:10.1080/02640414.2014.962578 · 2.10 Impact Factor
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ABSTRACT: Weight loss is the result of a sustained negative energy balance, which is typically achieved by decreasing food intake and/or increasing physical activity. Current evidence suggests that acute energy deficits of ~4820kJ elicit contrasting homeostatic responses when induced by exercise and food restriction but the response to government-recommended energy deficits is unknown. Twelve healthy men (mean(SD): age 24(5)years, body mass index 23.8(2.7)kg.m(-2), maximum oxygen uptake 55.4(9.1)mL.kg(-1).min(-1)) completed three 8h trials (control (Con), exercise-induced energy deficit (Ex-Def) and food restriction (Food-Def)) separated by 1 week. Thirty minutes of cycling at 64.5(3.2)% of maximum oxygen uptake was performed in Ex-Def from 0-0.5h, which induced an energy deficit of 1469(256)kJ. An equivalent energy deficit was induced in Food-Def (1478(275)kJ) by reducing the energy content of standardised test meals at 1h and 4h. Appetite ratings, acylated ghrelin and peptide YY3-36 concentrations were measured throughout each trial. An ad libitum meal was provided at 7h. Appetite was higher in Food-Def than Ex-Def from 4-8h (P=0.033) and tended to be higher across the entire 8h trial (P=0.059). However, energy intake at the ad libitum meal did not differ between trials (P = 0.634; Con 4376 (1634); Food-Def 4481 (1846); Ex-Def 4217 (1850) kJ). Acylated ghrelin was not related to changes in appetite but plasma PYY3-36 concentrations were higher in Ex-Def than Food-Def (P<0.05) and negatively correlated with changes in appetite across the entire 8h trial (P=0.037). An energy deficit of ~1475kJ stimulated compensatory increases in appetite when induced via calorie restriction but not when achieved by an acute bout of exercise. Appetite responses were associated with changes in plasma PYY3-36 but not acylated ghrelin concentrations and did not influence subsequent energy intake.Appetite 06/2014; 81. DOI:10.1016/j.appet.2014.06.003 · 2.52 Impact Factor