Effects of cold-water immersion on energy expenditure, ad-libitum energy intake and appetite in healthy adults

Introduction: Cold-water immersion is a popular method typically used to reduce exercise induced muscle damage and improve health and wellbeing. Despite these benefits, there is emerging evidence to suggest the temperature of the water exposure can influence energy intake in the subsequent hours. The study aim was to investigate the influence of water temperature on energy expenditure and post-water immersion ad-libitum energy intake in resting adults. Participants with a range of body masses, but otherwise healthy and physically active males (n = 10) and females (n = 5), participated in three randomised trials in a repeated measures crossover design, with a minimum of 7-days apart. Participants were immersed to sternum level for 30-minutes in either cold-water (16 °C), thermoneutral-water (35 °C) or a no-water thermoneutral ambient air control (26 °C). Participants completed appetite related visual analogue scales throughout and were presented with an ad-libitum homogenous pasta meal and asked to eat until ‘comfortably full’. Results: Repeated measures ANOVA showed participants consumed more energy after immersion in cold-water (2783 ± 909 kJ) versus both thermoneutral-water (1817 ± 862 kJ) and thermoneutral ambient air (1894 ± 233 kJ). There were no differences in any of the appetite VAS. Core temperature remained stable throughout the 30 min immersion period across trials, however an after-drop in core temperature was observed for 15 mins following cold-water immersion when compared to both thermoneutral water (P < 0.001), and thermoneutral air (P = 0.004). Although the exact mechanisms are yet to be elucidated, further research is required to identify if the after-drop in core temperature is a potential mechanism responsible for compensatory food intake post cold-water immersion. Conclusion: When presented with an ad-libitum meal directly after cold-water immersion, participants consumed more in comparison to both thermoneutral water immersion and thermoneutral ambient air. With cold water immersion becoming popular, these findings have practical and clinical relevance for individuals’ conscious about body mass management.