Effects of repeated short-term cold exposures on cold induced thermogenesis of women

The effects of repeated exposures to resting cold air (10 degrees C) on the shivering and thermogenic responses of women to standard cold stress were investigated. Ten women, aged 18 to 34 years, were divided into two groups of five women each. One group, the acclimated (A) was exposed ten times within 2 weeks, the first and the last exposures being the pre- and post-tests, respectively. The second group, the control (C) was exposed twice within 18 days. Measurements of rectal and skin temperatures, oxygen uptake, time to onset of shivering (TOS), and perceived cold were performed during all exposures. Shivering responses were evaluated by electromyography and visually. A significant (P less than 0.05) increase was seen in TOS (from 26.2 min to 55.6 min), and a significant decrease was seen in thermoregulatory heat production (from 14.78 kcal/h to -2.64 kcal/h) in group A; these changes were evident after about five exposures. It is concluded that the women became cold acclimated as a result of the repeated short-term resting cold air exposures.