Mild dehydration does not reduce postexercise appetite or energy intake

Kelly, P.J., Guelfi, K.J., Wallman, K.E. and Fairchild, T.J. (2012) Mild dehydration does not reduce postexercise appetite or energy intake. Medicine & Science in Sports & Exercise, 44 (3). pp. 516-524.

Abstract

Purpose: It has now been established that exercise performed under various environmental conditions may affect acute energy intake and appetite-related hormones. The exact mechanism linking acute energy intake and exercise remains unknown, although indirect evidence suggests a possible role for hydration status. Therefore, the purpose of this study was to investigate the interaction of exercise and hydration status on subsequent energy intake and appetite-related hormones. Methods: In a randomized, counterbalanced design, 10 physically active males completed three experimental trials in a fasted state: exercise when hydrated (0%-1% of body mass), exercise when dehydrated (-1% to -2% of body mass), and a hydrated resting control. Exercise consisted of treadmill running for 45 min at 70% (V) over dotO(2peak). Participants were then given access to a buffet-style breakfast from which they could consume ad libitum. Blood was sampled regularly during trials for appetite-related hormones. Results: There were no significant differences in total energy intake between trials (P = 0.491); however, relative energy intake was significantly higher in the control (4839 +/- 415 kJ, P < 0.001) compared to hydrated (1749 +/- 403 kJ) and dehydrated exercise (1656 +/- 413 kJ) conditions. Exercise performed in a dehydrated state resulted in significantly lower concentrations of ghrelin compared with control (P = 0.045) and hydrated exercise conditions (P = 0.014). Conclusions: Exercise significantly decreased relative energy intake compared with resting control; however, energy intake (relative and total) was no different between the exercise conditions (dehydrated vs hydrated). Despite similar energy intake between trials, exercise in a dehydrated state resulted in a significantly lower concentration of ghrelin, a hormone responsible for stimulating appetite.

Publication Type:	Journal Article
Murdoch Affiliation:	School of Chiropractic and Sports Science
Publisher:	Lippincott Williams & Wilkins
Copyright:	© 2012 The American College of Sports Medicine
URI:	http://researchrepository.murdoch.edu.au/id/eprint/7434

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