Cold shock response in healthy children: reassessment and first comparison between cold and warm water immersion.

Introduction: Swimming and diving are popular recreational activities and essential skills to prevent death from drowning. While most drownings occur in cold water, cold shock response is discussed as a major cause of drowning. Until now, the data on the physiology of drowning and cold shock response in children are scarce, while drowning remains a significant concern in this population. This study was conducted to investigate the cold shock response in healthy children and compare cold and warm water immersion. Methods: Participants were first immersed up to the neck in warm water (34 °C, close to thermoneutral) and then in cold water (11 °C), while skin temperature, ECG, heart rate, respiratory rate, oxygen saturation and peripheral perfusion index were continuously monitored. Results: Heart rate and respiratory rate remained constant in warm water. In cold water, heart rate increased by 31% and respiratory rate by 58%, peaking at 30 s and beginning to normalize after 60 s. Conclusion: The current study presents new data on the cold shock response in healthy children and the first comparison between cold water immersion and warm water immersion in this population. Data showed that immersion into 11 °C (52 °F) cold water leads to significant increases in heart rate and respiratory rate, in contrast to immersion in warm water. Remarkably, there is a lower intensity of the cold shock response in children compared to adults.