It is a well-known phenomenon: women are more prone to cold hands and feet than men, and young and thin women are even more affected by the phenomenon. How to explain this?
On average, the temperature of women’s hands is 1.5 ° C lower than that of men. On the other hand, the body temperature does not differ.
The main explanation for these “cold extremities” is that women’s blood vessels constrict more quickly in cold weather, slowing blood flow and reducing overall heat loss. The consequence is that the body stays at the right temperature, but the hands and feet (the external heat regulators of the body which protrude with a relatively large area) cool down.
It has to do with the receptors that control the narrowing of blood vessels: in women, they are more sensitive to cold temperatures under the action of estrogen, the female hormones. This is also the reason why women are more prone to “white finger” syndrome. In a cold temperature, the vessels constrict so much that the fingers are barely supplied with blood and they turn white.
In the evening before going to sleep, the blood vessels in our hands and feet widen so that the body can cool down. This is probably why vasodilatory activities like a hot foot bath, a hot drink, or… sex make you feel drowsy. Conversely, food or a cold drink before going to sleep causes the blood vessels to narrow., keeping us alert and awake. The cold feet of women, with their narrowed vessels, have the same effect: they interfere with sleep.