As temperatures stay high after another heatwave, waking up hot and sweaty may seem like an unavoidable summer side effect. But doctors have issued a reminder to pay attention to how often it happens, as it can sometimes be linked to a deadly disease.
Sweating is the body's natural way of cooling down, particularly when the mercury is soaring. Official NHS guidance says excessive sweating can happen even when the body does not need to cool down, and this could be linked to an underlying condition or medication.
When night sweats should not be dismissed
Drenching night sweats that repeatedly soak your clothes or bedding, especially when sleeping in a cool room, should not be dismissed, warns Dr Jidi Kubes. The radiation oncologist and medical director at Proton Therapy Center in Prague says it could be a sign you have cancer.
His warning comes as the death of country music legend Dolly Parton, aged 80, has put cancer back in the spotlight. Parton died in Nashville on August 25 following a brief battle with cancer, according to her publicist.
Distinguishing normal sweating from a warning sign
Dr Kubes said: “The important distinction is whether there is an obvious explanation. If the room is cool but you are repeatedly waking with your pyjamas and bedding soaked through, that is different from simply feeling clammy on a hot night.”
The NHS says night sweats are when someone sweats so much that their nightclothes and bedding become soaking wet, even though their sleeping environment is cool. It advises speaking to a GP if they happen regularly, wake you up or cause concern.
Other causes and when to seek advice
There are many possible explanations that have nothing to do with cancer. The NHS lists menopause, anxiety, some medicines, low blood sugar, alcohol and excessive sweating among potential causes, while infections can also trigger night sweats.
However, Cancer Research UK says very heavy, drenching night sweats can be a general symptom of cancer and should be discussed with a doctor, particularly when there is no obvious explanation.
Night sweats are particularly associated with lymphoma, where they can occur alongside other so-called B symptoms. Cancer Research UK says these can include unexplained fevers and significant unintended weight loss, while painless swollen lymph nodes in the neck, armpit or groin are another common lymphoma symptom.
Dr Kubes said people should seek medical advice sooner if severe sweating is accompanied by unexplained weight loss, persistent fatigue, recurring fevers or painless swelling. He stressed that cancer is “far from the most common explanation” for night sweats.
The NHS also advises people with regular night sweats not to wait if they are worried, particularly if they also have a high temperature, cough, diarrhoea or unexplained weight loss. One or two sweaty nights during a heatwave are therefore unlikely to mean something serious on their own. But persistent, unexplained drenching sweats are worth raising with a GP, who can assess the symptom alongside any other changes in your health.
