As others have pointed out, some amount of sweating is normal, and you don't want to get too cold in your sleep. It sounds like you're saying that you're sweating excessively while you sleep and this is a recent change. Here are three things you can do to keep from overheating while you sleep:
- Use blankets made from breathable material. Often when we sweat it is because the air around us isn't circulating. Have you ever seen a movie where someone wanted to lose some water weight quickly so they wore a garbage bag so they'd sweat it off? If you're using sheets or blankets that don't breathe then that's what you're doing to yourself at night.
Materials that don't breathe are typically synthetic materials. For example a blanket made out of any of these materials most likely doesn't breathe: fleece, polyester, microflannel. Materials that breathe are typically natural materials like cotton, wool, silk, and down.
If your sheets, blanket or bedspread are made from synthetic materials that don't breathe then that's the most likely culprit. Try swapping them out with all cotton sheets and a wool blanket. Or, the best solution for cold climates, use 100% cotton sheets with a quality down duvet.
A note on getting a quality down duvet: You want a down duvet that contains mostly down and only a few feathers. It is the down that breathes and maintains your body temperature so well. Feathers are often used in duvets as filler. A duvet that contains a lot of feathers won't be much better than a cheap synthetic blanket. To get the breatheability and comfort benefits from down you need a high quality duvet that is filled 90% to 95% with down and only 10% to 5% with feathers. Even the highest priced duvets sold at places like Sears, Bed Bath and Beyond, Walmart, and Cotsco most likely do not fit this bill. How do you know if the duvet contains 90% to 95% down? Most duvets available at mainstream stores in the United States do not. If the manufacturer does not advertise that the duvet contains 90% - 95% down, then it doesn't. You'll need to search the internet and learn what makes a good duvet, so you'll know what to look for in a duvet and where you can find them.
Here are a couple of links to get you started. The information on this website is excellent. Unfortunately the owner has retired and they no longer sell duvets, so you'll have to find another duvet maker who makes quality duvets. Fortunately their website is still up and the down duvet information is still accessible. If you can find another maker who makes duvets as good as this place, then you're all set:
Sleep in clothes made from breathable material: The same factors that apply to your bed sheets and blankets also apply to the clothes you wear while you sleep. Avoid synthetic materials that don't breathe; Wear clothes made only from breathable fibers. Cotton, wool, and silk are excellent material for clothes you're going to wear to sleep.
What you're eating or drinking before bed, or earlier in the day, could be affecting your metabolism and causing you to get hot at night. For example alcohol, wheat, milk, or caffeine can make some people overheat while they sleep. Investigate on the internet and conduct your own experiments by removing suspect foods from your diet temporarily to see if you notice a change. Since you mention that the sweating at night is a recent change, alcohol is a good place to start. Many people find that alcohol affects their sleep pattern and body temperature differently as they get older - it wakes them up in the middle of the night and/or makes them hot.
When those three things are all in order, and the temperature of the room you are sleeping in is reasonable, then you should find your body temperature comfortable throughout the night.