Thermal and metabolic responses to cold-water immersion at knee, hip, and shoulder levels

Lee, Dae T., Michael M. Toner, William D. McArdle, Ioannis S. Vrabas, and Kent B. Pandolf. Thermal and metabolic responses to cold-water immersion at knee, hip, and shoulder levels. J. Appl. Physiol. 82(5): 1523–1530, 1997.—To examine the effect of cold-water immersion at different depths on thermal and metabolic responses, eight men (25 yr old, 16% body fat) attempted 12 tests: immersed to the knee (K), hip (H), and shoulder (Sh) in 15 and 25°C water during both rest (R) or leg cycling [35% peak oxygen uptake; (E)] for up to 135 min. At 15°C, rectal (Tre) and esophageal temperatures (Tes) between R and E were not different in Sh and H groups ( P > 0.05), whereas both in K group were higher during E than R ( P 0.05). During R and E, the magnitude of Tre change was greater ( P 0.05). Total heat flow was progressive with water depth. During R at 15 and 25°C, heat production was not increased in K and H groups from control level ( P > 0.05) but it did increase in Sh group ( P < 0.05). The increase in heat production during E compared with R was smaller ( P < 0.05) in Sh (121 ± 7 W/m2 at 15°C and 97 ± 6 W/m2 at 25°C) than in H (156 ± 6 and 126 ± 5 W/m2, respectively) and K groups (155 ± 4 and 165 ± 6 W/m2, respectively). These data suggest that Tre and Tes respond differently during partial cold-water immersion. In addition, water levels above knee in 15°C and above hip in 25°C cause depression of internal temperatures mainly due to insufficient heat production offsetting heat loss even during light exercise.