Understanding the Biological Mechanism of Hot Flushes

Comprehending the psychological and biological mechanisms of hot flushes is important in finding treatments that will work and at the same time will be acceptable for those that survived breast cancer.

Hot flushes are most likely caused by the hormonal changes that follow menopause, but can also be affected by lifestyle and medications. A diminished level of estrogen has a direct effect on the hypothalamus, the art of the brain responsible for controlling appetite, sleep cycle, sex hormones and body temperature. Through a poorly understood biological mechanism, the drop in estrogen during menopause confuses the hypothalamus, which is sometimes referred to as the body’s ‘thermostat’ and makes it reads ‘too hot’.

The brain responds to this report by broadcasting an all out alert to the heart, blood vessels and nervous system, stating: Get rid of the heat!. The message is transmitted by the nervous system’s chemical messenger, epinephrine and other related compounds: norepinephrine, prostaglandin, and serotonin. In response to the message delivered to target organs, the heart pumps faster, the blood vessels in skin dilate to circulate more blood to radiate off the heat and the sweat glands release sweat in order to cool the body.

By this heat-releasing mechanism, the body keeps someone from overheating, but when the process is triggered instead by a drop in estrogen, the brain’s confused response can make a menopausal woman very uncomfortable. Some women’s skin temperature can rise six degrees centigrade during a hot flush. The body cools down when it shouldn’t, thereby making them miserable: soaking wet in the middle of a board meeting or in the middle of a good night’s sleep.