Cyclic changes in female reproductive hormones also may impact thermoregulatory responses to cold.
Data suggest that the onset of shivering occurs sooner in the luteal phase [80] when estrogen and progesterone levels peak, although this finding has been challenged [68] and there are no data to suggest that differences in the absolute starting core during cold exposure places a women at higher risk for hypothermia in the follicular vs. luteal phase.
Amenorrheic women cannot maintain their core temperature during exercise in cold air as well as their eumenorrheic counterparts, even if they have a similar body composition profile. [69] Evidence Statement .