Cardiovascular And Mood Responses To An Acute Bout Of Cold Water Immersion

Abstract

METHODS: Data was collected on 41 active adults who completed a 11km road race. Age (mean±standard deviation [SD]): 44.7±15.7 years; VO 2 max: 42.7±9.2 ml/kg/min; percent body fat: 22.4±9.6%. CRI was assessed at baseline for 10 minutes in a supine position in a thermoneutral environment. At the road race, CRI was assessed for 2 minutes pre-race and post-race in the supine position. Heart rate and oxygen saturation were assessed alongside CRI. Environmental conditions were captured surrounding the race. Core temperature was assessed post-race. Descriptive statistics (mean±SD) were calculated and paired-samples t-tests were utilized to compare baseline to pre-race, baseline to post-race, and pre-race to post-race. RESULTS: Post-race CRI (mean ± SD: 0.70±0.32) significantly diminished compared to baseline values (0.91±0.07; p<0.001). Post-race CRI was significantly diminished (p<0.001) compared to pre-race CRI measures (mean±SD: 0.88±0.09). Resting heart rate increased from baseline (mean±SD: 59.6±10.4 bpm) to pre-race (65.4±11.2 bpm) and to post-race (85.1±16.9 bpm). Runners were characterized as hyperthermic following the race (core temperature: 38.90±1.20 ºC). Environmental conditions upon finishing the race were 22.78 ºC, 53% RH, and 21.67 ºC WBGT. CONCLUSIONS: Following physically demanding exercise in the heat, CRI monitoring may be able to detect changes resulting from increased physiological stress and may be utilized to prevent collapse. Future studies should assess the extent to which thermal stress is correlated to changes in CRI.