The Effect Of 20 Km Running On Appetite Regulation In Long Distance Runners

Abstract

Acute exercise has been shown to reduce subjective appetite and spontaneous energy intake during subsequent meal. However, reduction of energy intake after exercise may cause unfavorable response such as delayed recovery of exercise capacity and accumulated fatigue. PURPOSE: To investigate time course of changes in appetite-related hormonal responses and energy intake after 20 km running in trained long distance runners. METHODS: Twenty three male long-distance runners (20.0 ± 0.3 years, 171.2 ± 1.9 cm, 56.3 ± 1.0 kg, VO2max: 67.1 ± 1.0 ml/kg/min) completed 2 trials on separate days: either exercise trial with conducting 20 km outdoor running (EX) or control trial with identical period of rest (CON). Blood samples were collected repeatedly to determine plasma ghrelin, peptide YY3-36 (PYY3-36), serum free fatty acids (FFA), growth hormone (GH), myoglobin (Mb) and creatine kinase (CK) concentrations. Energy intake during buffet test meal was also measured at 30 min after exercise or rest. RESULTS: Blood lactate concentration did not change significantly after 20 km running. Serum FFA, GH, Mb and CK concentrations was significantly increased after 20 km running (P < 0.05). Furthermore serum FFA, Mb and CK concentrations remained significantly higher than baseline value at 30 min after exercise (P < 0.05). Plasma ghrelin concentration was significantly decreased after 20 km running (P < 0.05). In contrast, plasma PYY3-36 concentration did not change significantly after 20 km running. Absolute energy intake during buffet test meal was significantly lower in EX (1325 ± 55 kcal) than in CON (1529 ± 55 kcal), and there was relatively large individual variability for exercise-induced change of energy intake (-40.2% to 12.8%). However, exercise-induced change of energy intake was not significantly associated with plasma ghrelin or PYY3-36 responses. CONCLUSIONS: These results demonstrated that 20 km running significantly decreased plasma ghrelin concentration and absolute energy intake among well-trained long distance runners. However, the exercise-induced reduction of energy intake was not associated with ghrelin or PYY3-36 responses.