There are a number of causes for sweating in your sleep. Here are examples of some commons ones to consider.
Example 1: infection
I recently had a 74 year old gentleman come in with a complaint of night sweats for 3 months. He told me he had been to 4 doctors, had a full malignancy work up that included a CT scan of his chest/ abdomen/ pelvis and exhaustive bloodwork. He was told he just has to live with it. He was becoming depressed because he would routinely wake up drenched and feeling very cold afterwards. He just wasn’t having a restful night. As he was talking I noticed these small pink and red spots on his fingers, a few had scabbed over. He hadn’t really paid much attention to them but said sometimes they were sore. I biopsied one and it revealed something called septic emboli. This is a sign of infective endocarditis- I ordered an echocardiogram of his heart and he had bacteria on his heart valve. These were spreading to his skin to cause the red spots (called Osler’s nodes) AND causing his night sweats. I put him on antibiotics and he cleared very quickly and was happy to finally get some rest at night within a couple of days of starting antibiotics.
Example 2: cancer
One of the earliest signs of a cancer, lymphoma in particular, can be night sweats. I think of night sweats as a ‘check engine light’ that can tell you to look for an underlying cause. Sometimes the sweats will be one of several symptoms such as chronic itching, fatigue or tiredness and shortness of breath.
Example 3 : hormones
One of the most common complaints from women going through menopause is going to bed cold and then feeling like they have to throw the sheets off in the middle of the night and feeling drenched! As hormonal levels fluctuate it’s really common for our body temperature to change. I also remind women that this can mean you go to bed with clear skin, have a hot flash that flares their rosacea, and they wake up with a breakout. So frustrating!