Why Does My Body Heat up When I Sleep?

Why Does My Body Heat up When I Sleep?

Have you ever gone to bed in a cool room and still woken up sweaty and hot? Do you feel like you're lying under the sun on a hot beach day, and yet you're in your bedroom, sleeping, in the middle of winter?

Even if it sounds annoying and odd, this is actually not that uncommon. Your room's temperature may be perfectly adjusted, and yet you still end up feeling hot. This is because room temperature alone doesn't cut it. If you're a hot sleeper other factors can also be the reason behind it.

Like, for example, maybe you have the wrong bedding for the time of year. Maybe you use wool bedding when you should be using bamboo instead. Or you sleep in the wrong pyjama material. Also, certain medications and certain health conditions can make you feel hot at night.

Here I'll tell you more about the most common reasons why you get so hot while you sleep and what you can do about it.

You're Using the Wrong Kind of Bedding or Sleepwear

Bedding is very important for a good night's sleep, and yet it's often underestimated. Bedding functions as insulation, so thick bedding (like wool bedding) traps more heat than thin, light material bedding (like bamboo bedding). The same goes for sleepwear and so too your mattress.

In a 2016 study from the University of Sydney, Australia, researchers compared wool sleepwear to cotton sleepwear and looked at their effects on sleep quality. In colder temperatures (63°F/17°C), wool sleepwear “promoted a greater ease of sleep onset” than cotton, but in warmer temperatures (72°F/22°C), it was cotton that promoted better sleep.

So, the moral of the story is that if you sleep in a warm climate, make sure to use bamboo or cotton bed linen as well as quilts, mattress protectors, and sleepwear. When it comes to a cooling mattress, your best bet is to find one with a Tencel or bamboo fabric cover or any other features that promote thermal conductivity and can allow heat to be quickly and effectively pulled away from your body.

Blame It on the Hormones

Hormone levels imbalance can cause hot flashes and night sweats in particular. Lots of women experience hot flashes and night sweats when they are in the premenstrual phases the body goes through before menstruation. However, this is also a common occurrence in perimenopause and during menopause.

This happens because of the fluctuations in progesterone and estrogen hormone levels.

Pregnancy also causes a variety of hormonal changes that can affect your core body temperature.

Also, hyperthyroidism, a condition in which your thyroid gland produces too many hormones, can be the reason why you may experience excessive sweating at night and feel hot.

It's best to talk to your doctor about what to do if any of these symptoms become too debilitating for your sleep quality.

Activities You Do Before Going to Bed

Your pre-bedtime routine is a key part of building healthy sleeping patterns. Certain activities that you do before your bedtime can actually be the culprit behind increased core body temperature and make you feel hot when you sleep.


Sure, exercise is super important for a healthy body and mind and for a good night's sleep. However, if you exercise too vigorously within 60-90 minutes of going to bed, it can negatively impact your sleep. You may start experiencing night sweats, feel hot, and sometimes even get shivers.

So next time you exercise in the evening, make sure it's at least 90 minutes before you plan on going to bed because this is the time when “the core body temperature starts to fall," after which you will start feeling sleepy.


Lots of us are practically addicted to caffeine; it's the only thing sometimes that gets us through the day! But, consuming caffeinated drinks (coffee, energy drinks, black tea) in the evening can meddle with our sleep. It can make you more alert and fidgety, and it can also increase your core body temperature.

That's why it's best to stop drinking coffee in early midday, around 2-3 p.m. at the latest. Make sure there are at least 6 hours between your last cup of coffee and your bedtime.


Stress greatly impacts many bodily processes, and it's responsible for all kinds of physical and psychological issues. Your blood vessels constrict when you're feeling stressed and make your skin temperature drop while your core body temperature rises.

So, the key is to have a relaxing pre-bedtime routine. Turn off any mobile devices, read a book or listen to some relaxing music, or light some candles, and turn off the lights; make a sleeping environment in which you'll actually want to sleep to.


Feeling hot during sleep can be annoying, and sometimes it can even interfere with your sleep. But as you saw here, there are ways to tackle it. Sometimes it is just the hot weather, and you need better sleepwear and linen.

However, if you keep experiencing hot flashes, it's best to consult with a doctor and see whether any underlying medical issue isn't the culprit behind it. Hot flashes and feeling hot at night can happen due to many reasons, and it's always best to be safe than sorry.