Post-exercise cold water immersion: effect on core temperature and melatonin responses.
To study the effect of post-exercise cold water immersion (CWI) on core temperature and melatonin responses, 10 male cyclists completed two evening (~1800 hours) cycling trials followed by a 15-min CWI (14 °C) or warm water immersion (WWI; 34 °C), and were then monitored for 90 min post-immersion. The exercise trial involved 15 min at 75 % peak power, followed by a 15 min time trial. Core (rectal) temperature was not different between the two conditions pre-exercise (~37.4 °C), post-exercise (~39 °C) or immediately post-immersion (~37.7 °C), but was significantly (p < 0.05) below pre-exercise levels at 60 and 90 min post-immersion in both conditions. Core temperature was significantly lower after CWI than WWI at 30 min (36.84 ± 0.24 vs. 37.42 ± 0.40 °C, p < 0.05) and 90 min (36.64 ± 0.24 vs. 36.95 ± 0.43 °C, p < 0.05) post-immersion. Salivary melatonin levels significantly increased (p < 0.05) from post-exercise (~5 pM) to 90 min post-immersion (~8.3 pM), but were not different between conditions. At 30 and 90 min post-immersion heart rate was significantly lower (~5-10 bpm, p < 0.01) after CWI than WWI. These results show that undertaking either CWI or WWI post-exercise in the evening lowers core temperature below baseline for at least 90 min; however, the magnitude of decrease is significantly greater following CWI. The usual evening increase in melatonin is unaffected by exercise or post-exercise water immersion undertaken between ~1800 and ~2000 hours.
School of Sport Science, Exercise and Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. 10010789@student.uwa.edu.au
Elisa
E
Robey
Brian
B
Dawson
Shona
S
Halson
Carmel
C
Goodman
Warren
W
Gregson
Peter
P
Eastwood
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D003080:Cold Temperature; D006801:Humans; D007101:Immersion / Q000503:physiopathology*; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D012463:Saliva / Q000737:chemistry*
D008550:Melatonin