Niu, Xinting; Han, Peng; Tang, Zujie; Huang, Jin; Li, Li; He, Hui; Zhang, Wenzhong; Zhao, Li; Zhao, Lei

Journal of Strength and Conditioning Research 37(1):p 114-122, January 2023, DOI: 10.1519/JSC.0000000000004160

PURPOSE:

To investigate women's fat oxidation under cold stress during  incremental exercise testing and 2) to compare the effect of cold stress on fat oxidation between the sexes.

PROCEDURES:

26 healthy subjects performed 2 incremental exercise tests to determine maximal oxygen uptake (Vo2max) on a treadmill in different ambient temperatures.

Cardiopulmonary variables were continuously recorded during incremental exercise tests.

Maximal fat oxidation (MFO) and the corresponding exercise intensity (Fatmax) were determined from the fat oxidation curve constructed by indirect calorimetry.

CONCLUSIONS:

Both men and women relied more on fat oxidation in cold environment.

Compared with men, fat oxidation was significantly greater in women in the cold environment from 50 to 70% Vo2max.

There were no significant differences in the change of fat oxidation as exercise intensity increased between the sexes.

Women had a greater MFO and Fatmax than men in the cold environment.

When MFO was the dependent variable, sex, fat-free mass, fat mass, Vo2max, and temperature accounted for 48% of its variability. It was therefore concluded that cold stress enhances fat oxidation in women.

Compared with men, women have significantly higher value and rely more on fat oxidation to supply energy in the cold environment, although the increasing level of fat oxidation was similar between the sexes. These factors may have important implications in the individualization of exercise prescription in cold conditions for both men and women.

IN PLAIN ENGLISH:

In cold weather, the body naturally revs up its metabolism to maintain a healthy core temperature, independent of sex. Women also have less muscle mass than men, thus more relative fat mass which can be tapped for energy for that needed boost in metabolism. Hence, it makes sense that women will burn more relative fat in cold conditions, so to prepare for bikini season it may be prudent to hit the North Pole for a few weeks prior to that trip to the equator.