Purpose: The performance of exercise while immersed in cold water has been shown to influence energy intake in the subsequent meal. In addition, cold water immersion (CWI) itself has been shown to reduce the concentration of the hormone leptin, high concentrations of which signal satiety. Taken together, these findings raise the question of whether the common practice of postexercise CWI by athletes acutely affects energy intake. Hence, this study investigated the acute effect of CWI after exercise on subsequent energy intake and macronutrient preferences as well as the circulating levels of a range of appetite-related hormones.
Methods: Ten physically active men participated in three randomized, counterbalanced trials consisting of 40 min of treadmill running (70% VO(2peak)), followed by 20 min of CWI (15°C), neutral water immersion (NWI; 33°C), or a resting control with no immersion (CON). Participants were then given a 30-min access to a buffet-type breakfast of precisely known quantity and nutrient composition from which they could consume ad libitum.
Results: Participants consumed significantly more energy after both CWI (mean ± SD = 4893 ± 1554 kJ, P = 0.006) and NWI (5167 ± 1975 kJ, P = 0.010) compared with CON (4089 ± 1585 kJ). However, there was no significant difference in total energy intake between the CWI and the NWI trials (P = 0.595). These changes were associated with a significant interaction effect of time and trial on both leptin (P = 0.045) and active ghrelin (P = 0.046).
Conclusion: Postexercise water immersion is associated with higher energy intake in the subsequent meal compared with CON. This is an important consideration for trained men using water immersion as a method of recovery from exercise.