THE SCIENCE BEHIND night sweats

In most cases, you can blame night sweats on changing hormones that mess with the hypothalamus, the part of your brain that regulates your body temperature.

When you experience a night sweat, it’s because your core body temperature (the human body is meant to hover about 37°C) has gone up, similarly to how it does when you exercise or sit in a hot room – despite the fact you’re sound asleep in a relatively temperature-controlled environment. When your temp rises, your heart rate speeds up and the blood vessels in your skin dilate

(or widen) to boost blood flow to the skin’s surface, which helps excess heat leave your body. The result? Your skin gets warm to the touch. When your heart rate peaks, the sweating starts, says Dr Streicher. “This sweating can be mild, where your skin feels a little damp to the touch, or it can be profuse, dripping-down-your-back sweating,” she says. “This heatwave is often followed by shivering and chills as your body cools off.”

The signalling receptors in this temperature regulation centre are controlled by oestrogen. This is why, when oestrogen tanks during perimenopause, the vast majority of women will experience night sweats and hot flushes, says Dr Streicher. Yet this part of the brain is also sensitive to fluctuations in other hormones, such as serotonin and norepinephrine. When changes in any of these hormones take place – say, when serotonin is too high due to a change in medication or norepinephrine skyrockets during times of stress – the hypothalamus freaks out, thinking your core body temp is too hot and orders the body to cool down ASAP (hence the sweating). And as you age, the body gets its temperature signalling wrong more frequently, setting off more of that sweaty, sheet-drenching discomfort.