Swimming may stimulate appetite and food intake but empirical data are lacking. This study examined appetite, food intake, and plasma acylated ghrelin responses to swimming. Fourteen healthy males completed a swimming trial and a control trial in a random order. Sixty min after breakfast participants swam for 60？min and then rested for six hours. Participants rested throughout the control trial. During trials appetite was measured at 30？min intervals and acylated ghrelin was assessed periodically (0, 1, 2, 3, 4, 6, and 7.5 h. ). Appetite was suppressed during exercise before increasing in the hours after. Acylated ghrelin was suppressed during exercise. Swimming did not alter energy or macronutrient intake assessed at buffet meals (total trial energy intake: control 9161？kJ, swimming 9749？kJ). These findings suggest that swimming stimulates appetite but indicate that acylated ghrelin and food intake are resistant to change in the hours afterwards. 1. Introduction Regular physical activity is important for the maintenance of body weight and its composition within a healthy range [1, 2]. All forms of physical activity can contribute to successful energy balance by increasing daily energy expenditure. Swimming is an attractive mode of physical activity due to the reduced musculoskeletal and thermoregulatory stresses (i.e., elevation in body temperature) imposed in comparison with other land-based activities such as running and cycling. Swimming may therefore offer an appealing form of physical activity for individuals seeking to prevent weight gain and/or to maintain a reduced body weight after successful weight loss. Despite the attractiveness of swimming as a mode of physical activity, the ability of swimming to favourably influence body weight and body composition remains contentious. In obese individuals research has shown that swimming may not induce body weight and fat loss [3, 4] whereas walking and cycling interventions of similar intensity and duration do . Considering the heightened energy output elicited by all forms of exertion the most logical explanation for these findings is that swimming stimulates a compensatory increase in energy intake . This notion is consistent with anecdotal reports of swimming stimulating appetite. Specifically, it has been stated that individuals often feel like “eating a horse” after an acute bout of swimming . This suggestion is consistent with empirical research which has described elevations in energy intake after cycling-based exercise performed on a modified ergometer in cold water [5, 7]. Despite
J. E. Donnelly, S. N. Blair, J. M. Jakicic, M. M. Manore, J. W. Rankin, and B. K. Smith, “Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults,” Medicine and Science in Sports and Exercise, vol. 41, no. 2, pp. 459–471, 2009.
H. M. Seagle, G. W. Strain, A. Makris, and R. S. Reeves, “Position of the American Dietetic Association: weight management,” Journal of the American Dietetic Association, vol. 109, no. 2, pp. 330–346, 2009.
H. Tanaka, D. R. Bassett Jr., and E. T. Howley, “Effects of swim training on body weight, carbohydrate metabolism, lipid and lipoprotein profile,” Clinical Physiology, vol. 17, no. 4, pp. 347–359, 1997.
L. J. White, R. H. Dressendorfer, E. Holland, S. C. McCoy, and M. A. Ferguson, “Increased caloric intake soon after exercise in cold water,” International Journal of Sport Nutrition and Exercise Metabolism, vol. 15, no. 1, pp. 38–47, 2005.
D. R. Broom, D. J. Stensel, N. C. Bishop, S. F. Burns, and M. Miyashita, “Exercise-induced suppression of acylated ghrelin in humans,” Journal of Applied Physiology, vol. 102, no. 6, pp. 2165–2171, 2007.
D. R. Broom, R. L. Batterham, J. A. King, and D. J. Stensel, “Influence of resistance and aerobic exercise on hunger, circulating levels of acylated ghrelin, and peptide YY in healthy males,” American Journal of Physiology, vol. 296, no. 1, pp. R29–R35, 2009.
J. V. G. A. Durnin and J. Womersley, “Body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years,” British Journal of Nutrition, vol. 32, no. 1, pp. 79–97, 1974.
A. Flint, A. Raben, J. E. Blundell, and A. Astrup, “Reproducibility, power and validity of visual analogue scales in assessment of appetite sensations in single test meal studies,” International Journal of Obesity, vol. 24, no. 1, pp. 38–48, 2000.
B. E. Ainsworth, W. L. Haskell, and W. L. Haskell, “Compendium of physical activities: an update of activity codes and MET intensities,” Medicine and Science in Sports and Exercise, vol. 32, no. 9, pp. S498–S504, 2000.
N. A. King, V. J. Burley, and J. E. Blundell, “Exercise-induced suppression of appetite: effects on food intake and implications for energy balance,” European Journal of Clinical Nutrition, vol. 48, no. 10, pp. 715–724, 1994.
A. J. van der Lely, M. Tsch？p, M. L. Heiman, and E. Ghigo, “Biological, physiological, pathophysiological, and pharmacological aspects of ghrelin,” Endocrine Reviews, vol. 25, no. 3, pp. 426–457, 2004.
N. A. King, A. Lluch, R. J. Stubbs, and J. E. Blundell, “High dose exercise does not increase hunger or energy intake in free living males,” European Journal of Clinical Nutrition, vol. 51, no. 7, pp. 478–483, 1997.
L. P. Novak, W. A. Woodward, C. Bestit, and H. Mellerowicz, “Working capacity, body composition, and anthropometry of Olympic female athletes,” Journal of Sports Medicine and Physical Fitness, vol. 17, no. 3, pp. 275–283, 1977.
P. ？rámek, M. ？ime？ková, L. Jansky, J. ？avlíková, and S. Vybíral, “Human physiological responses to immersion into water of different temperatures,” European Journal of Applied Physiology, vol. 81, no. 5, pp. 436–442, 2000.