Effects of Exercise in the Cold on Ghrelin, PYY and Food Intake in Overweight Adults

PURPOSE: Exercise in cold water has been shown to simulate post-exercise energy intake (EI) in normal-weight individuals. However, the effect of cold exercise on EI in overweight individuals has yet to be examined. The present study investigated the impact of brisk walking in a cold (8˚C) and neutral (20˚C) environment on post-exercise EI and appetite hormone responses.

METHODS: Sixteen overweight participants (10 men, 6 women; age 50.1 ± 11.6 yr, body mass index 28.9 ± 4.2 kg[BULLET OPERATOR]m) completed a 45 min treadmill walk at 8°C and 20°C in a randomized, counterbalanced design. Participants were presented with an ad libitum buffet meal 45 min post-exercise and EI was covertly measured. Skin and rectal temperature were monitored throughout exercise and for 30 min post-exercise, and concentrations of the appetite hormones total ghrelin, acylated ghrelin, and total peptide YY (PYY) were assessed pre- and post-exercise, and pre- and post-meal.

RESULTS: EI was significantly greater following exercise in the cold (1299 ± 657 kcal; mean ± SD) compared with exercise in the neutral environment (1172 ± 537 kcal; mean ± SD) (P < 0.05). The change in the acylated ghrelin concentrations, and the acylated ghrelin AUC values were significantly greater during walking in the cold versus the neutral condition (P < 0.05).

CONCLUSION: These findings show that in overweight individuals, exercise in the cold stimulates post-exercise EI to a greater extent than exercise in a neutral environment.