Environmental and body temperatures of 52 divers in hyperbaric heliox

Rectal and skin temperatures were recorded over periods as long as 24 h on 52 divers at depths as great as 300 m. Chamber temperature and body temperatures are correlated with depth, and the correlation between chamber temperature and mean skin temperature is evaluated. To ensure thermal balance daytime chamber temperatures must change with depth in meters according to the relationship Tch = 28.23 +/- (0.0058 x depth). Nighttime chamber temperatures must change according to the relationship Tch = 27.6 + (0.0074 x depth). Daytime rectal temperatures change significantly with depth in a way described by a 2nd-order regression line. The linear rate of change is 0.0014 degrees C/m increasing from a sea level value of 36.62 degrees C in heliox. Daytime mean body temperature increases with depth by 0.001 degrees C/m from 35.3 degrees C. Daytime mean skin temperatures very with chamber temperature at a rate of 0.34 degrees C/degrees C, which is identical to that found for an unclothed person in 1 ATA air.