Science Questions

Why do I get hot sweats at night? I think I am going through the menopause. Jenny

This is a very common symptom of the menopause. Normally, your ovaries respond to a hormone signal from the brain by beginning to produce eggs, which produce oestrogen as they develop. In response to the oestrogen the brain switches off the hormone signal until the next cycle. Women are born with all the eggs they will ever have already in their ovaries and so as women age, they start to run out of eggs, meaning it cannot produce oestrogen. In response to this, the brain sends even higher levels of hormones to try to encourage the ovaries to produce eggs. It is this increase in hormones from the brain that can cause the symptoms of the menopause. Hormone replacement therapy (HRT) works by increasing oestrogen levels in the blood which, in turn, suppresses the release of the hormones produced by brain and preventing the symptoms. But the increased risk of breast cancer associated with HRT use means that it should probably not be used for longer than about 5 years.

December 2004