The physiological response of immersion in cold water and cooling rates during swimming in a group of children aged 10–11 years

Swimming is a popular activity in the United Kingdom (UK); however, cold water immersion often found in open waters in the UK is not without increased risk. Drowning is among the leading cause of accidental death in 1–14-year-olds in most countries. We examined whether children and adults exhibit similar cold shock responses; rates of cooling while swimming; and subjective recognition of cooling. Nineteen children aged 10–11 years voluntarily undertook a 5 min static immersion in 15 °C (59 °F) water. Ten of them completed a swim of up to 40 min. Resting heart rate, respiratory frequency, and inspiratory volume increased in all participants on initial immersion. The mean (± SD) cooling rate while swimming was 2.5 °C hr-1 (± 3.1°). No significant correlation was found between cooling rate and thermal sensation or comfort, implying a lack of subjective awareness in children. On comparing data from unacclimatized adults in 12 °C (53.6 °F) water, children showed a smaller cold shock response (p ≤ .05), and no difference was found in cooling rates during swimming.