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If your room is too hot or too cold, you’ll likely have trouble getting to sleep. A 2019 research review with human and animal studies found that the optimal room temperature for sleep is about 66 to 70°F (19 to 21°C).

Even if your room is the perfect temperature for you, it’s still possible to feel too warm during the night. Your bedding, pre-sleep routine, some medication, and certain medical conditions can all make you feel overheated.

In this article, we look at seven reasons why you may get hot when you sleep and examine possible solutions.

If you’re feeling too hot during the night, it may be because the temperature of your room is too warm. A 2012 research review found that exposure to heat during the night increases wakefulness and decreases slow-wave sleep and rapid eye movement sleep.

Humidity can also magnify the effect of heat by reducing your sweat’s ability to evaporate.

Your bedding acts as an insulator much like the insulation in your home. Thicker bedding tends to trap more heat than thinner bedding and wearing thick sleepwear can also lead to overheating.

Different fabrics have different heat-retaining properties and may influence your sleep quality.

A small 2016 studycompared the effects of cotton and wool sleepwear and polyester and wool bedding on sleep quality at temperatures of 63°F and 72°F (17°C and 22°C).

The researchers found wool sleepwear promoted sleep onset more than cotton at 63°F (17°C), but cotton promoted deeper sleep at 72°F (22°C).

The researchers found no difference between sleep onset or quality between polyester and wool bedding at either temperature.

The activities you perform before bedtime can potentially increase your body temperature and make it more difficult to fall asleep.

  • Exercise. A small 2018 research review found that evening exercise didn’t negatively impact sleep and actually had the opposite effect. But sleep onset may be impaired if vigorous exercise finishes within 1 hour of bedtime.
  • Caffeine. It’s well-documented that consuming caffeine close to bedtime can make it difficult to fall asleep. Along with increasing mental alertness, caffeine is associated with higher core body temperature, according to a small 2014 study.
  • Stressful activities. When you feel stressed, your blood vessels constrict. This action drops your skin temperature and increases your core body temperature, according to a 2015 study with animals.
  • Sex. Sex can improve sleep quality by releasing hormones that promote relaxation. However, vigorous sex that raises your heart rate may have the same effect as exercise.

If you sleep with other people or pets, the combined temperature of your bodies can raise the temperature under your bedding and in your room.

Bodies are constantly giving off heat as a byproduct of metabolism. The more bodies and the smaller the space, the quicker the area will heat up.

The average temperature of a human body is roughly 98.6°F or 37°C. If the temperature of the room is warmer than this, your body will absorb heat and actually have a cooling effect on the room.

A long list of medications can potentially raise your body temperature or disrupt your body’s ability to regulate its temperature.

Some commonly used medications that affect thermoregulation include:

Imbalances in your hormone levels can lead to night sweats or hot flashes.

Many females experience night sweats as part of premenstrual syndrome due to fluctuations in estrogen and progesterone levels.

Night sweats and hot flashes are two of the most common symptoms of menopause. Reductions in estrogen and other hormonal changes that aren’t fully understood are thought to cause these symptoms.

Pregnancy also leads to hormonal changes that increase blood flow and raise your core body temperature.

Hyperthyroidism and obstructive sleep apnea (which can affect a variety of hormones) are two more potential causes of why you feel hot and sweaty at night.

Many potential illnesses can lead to an increase in body temperature or cause night sweats. Infectious diseases that can cause elevated body temperature include:

Other conditions that can make your feel hot at night include:

Here are some ways you may be able to stop feeling overheated at night.

Underlying causeTreatment
Room temperature too high-Lower your heat.
-Open a window.
-Use a dehumidifier.
-Use a fan or air conditioning.
-Move your mattress to the floor.
-Have a cold shower before bed.
Bedding-Use fewer blankets.
-Choose lightweight and breathable fabrics.
Pre-sleep activities-Finish exercising at least 1 hour before bed.
-Avoid consuming caffeine in the late afternoon or evening.
-Minimize stressful activities near bedtime.
-Avoid vigorous sex before bed (nonvigorous sex may improve sleep quality).
Sleeping with other people or pets-If sleeping with other people, consider using a separate blanket.
-Consider opening a window or leaving the door open.
Medications-Contact your doctor and see if you can adjust your medications.
Hormonal conditions-Ask your doctor about the best treatment options for your particular condition.
Illness or infection-Try to treat the underlying condition.

Many potential factors can make you feel hot when trying to sleep. In some cases, you may feel hot because your room is too warm, or your bedding is too thick. Certain medications or underlying medical conditions can also contribute to feeling too hot.

If you find that changing the temperature of your room and your pre-bed habits doesn’t fix the problem, it’s a good idea to have an appointment with your doctor to rule out an underlying medical condition.