Hot flashes (a.k.a. hot flushes) are an extremely common uncomfortable condition associated with Menopauseplugin-autotooltip__plain plugin-autotooltip_bigMenopause

The decline in the number viable ovarian follicles, which leads to the menopause, is well documented (see Wikipedia), but, from an evolutionary perspective the reasons for its prevalence in humans are unknown.

Only a few other mammals* are known to exhibit menopause - including orcas, short-finned pilot whales and chimpanzees..

They are typically experienced as a rapid-onset feeling of intense heat, often with sweating, anxiety, and a rapid heartbeat, usually lasting from two to thirty minutes. They can occur several times a day, and their frequent occurrence often persists for several years.

Although the flashes are almost certainly a result of changing hormone levels, the exact cause(s) - and the triggering mechanism - are unknown.

Hot flashes are associated with declining levels of estrogen (estrogen withdrawal) and other hormonal changes. It does not appear that low levels of estrogen are the sole cause of hot flashes, as women who experience hot flashes have around the same plasma estrogen levels as women who do not have them, and prepubertal girls do not have hot flashes despite low estrogen levels.
There are indications that hot flashes may be due to a change in the hypothalamus's control of temperature regulation."

Source : Wikipedia

Note that although it's known that the brain's hypothalamus region is associated with body temperature control, exact details are unknown. See Thermoregulationplugin-autotooltip__plain plugin-autotooltip_bigThermoregulation

"The core temperature of a human is regulated and stabilized primarily by the hypothalamus, a region of the brain linking the endocrine system to the nervous system, and more specifically by the anterior hypothalamic nucleus and the adjacent preoptic area regions of the hypothalamus. As core temperature varies from the set point, endocrine production initiates control mechanisms to increase or decrease energy production/dissipation as needed to return the temperature toward th…