Why Do I Always Get *So Hot* When I Sleep?

In most cases, feeling a little warm in the middle of the night is normal. Your core body temperature fluctuates throughout the day and “starts to dip at night” to prep your body for sleep, says Thomas Kilkenny, DO, director of the Institute of Sleep Medicine at Northwell Staten Island University Hospital. But in order to let off heat, blood vessels in your skin will dilate, causing your skin temperature to rise, Dr. Kilkenny says. This process might make you feel a little toasty, at least temporarily, before the heat escapes your body.

Cooling off by shedding some layers (i.e., taking off blankets or your socks) can be a great quick fix. But if you're consistently waking up with sweat-soaked sheets, an underlying health or lifestyle issue may be to blame. Addressing the problem will not only keep you cool, but can also help you get more quality sleep.

Read on to learn the most common reasons why you're a hot sleeper, how to stay cool throughout the night, and when to see a doctor if it's sabotaging your slumber.

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1. It's your sleep environment

Sweating bullets when you sleep? It might be the room you're sleeping in. The following factors can play a role in overheating while sleeping, per Dr. Kilkenny:

• Hot or humid climate: “Hot weather and warmer, humid rooms may prevent the body from cooling down,” Dr. Kilkenny says. “The best temperature for sleep is 65 to 68 degrees Fahrenheit,” he adds.
• Heavy bedding: “Some sheet and blanket materials are designed to hold heat, causing us to feel warm,” he says.
• Warm pillows, mattresses, and mattress toppers: “Also think about the type of mattress and mattress topper,” he says. “Foam mattresses or toppers hold the heat more and do not allow the skin to breathe.” Same goes for memory foam pillows, which can trap heat.
• Heavy pajamas: If your PJs are thick or made of unbreathable materials (like fleece or wool), they can insulate heat.
• Sleeping partners and pets in the bed: Warm-blooded beings—like humans, dogs, and cats—radiate so much heat at night. At rest, the "average" person will generate approximately 105 watts of heat, according to Cornell University. That means your partner (or pet) can feel like a furnace in bed.

2. Your body's more sensitive to heat

Your body composition can make you more sensitive to heat. For example, people with a higher percentage of body fat may feel hotter at night. Dr. Kilkenny says having overweight causes us to feel warm. That's because when "blood vessels are insulated by fat cells," it limits the "ability to lose heat into the environment," he adds.

But keep in mind, not everyone with overweight will have night sweats—it just depends on the person. People with a higher proportion of lean muscle mass could also generate more heat, too, thanks to a quicker metabolism, according to a May 2023 review in the Nature of Science and Sleep.

3. You take certain medications

The meds you're taking could also be responsible for nighttime perspiration. Certain drugs, especially antidepressants, "can cause people to feel hot and lead to excessive sweating,” Dr. Kilkenny says.

But antidepressants aren’t the only drugs with sweaty side effects. In fact, there’s a long list of medicines that may make you more sensitive to heat. Some of these include the following, per the National Library of Medicine (NLM):

• Antihistamines
• Amphetamines or other stimulants, including those found in drugs that suppress your appetite
• Antibiotics
• Antipsychotic medicines
• Blood pressure medicines
• Cholesterol medicines (statins)
• Decongestants
• Diabetes medicines
• Overactive bladder medicines
• Pain relievers (non-steroidal anti-inflammatories)
• Parkinson medicines

If you think a medication you're taking is making you hot at night, don't stop taking it quite yet. Talk to your doctor first, who can help decide whether the drug is causing your heat intolerance. If it's safe, they may prescribe you a lower dose or put you on an alternative med.

4. You could have a sleep disorder

Chronic overheating at night could also be a sign of a sleep disorder. “Obstructive sleep apnea, especially, and other sleeping disorders can disrupt sleep and at times cause a struggle to breathe at night,” Dr. Kilkenny says. “This leads to excessive stress on the body, which causes the temperatures to rise.”

Other common symptoms of sleep apnea include the following, per the Mayo Clinic:

• Loud snoring
• Episodes in which you stop breathing during sleep—which would be reported by another person
• Gasping for air during sleep
• Waking up with a dry mouth
• Morning headache
• Difficulty staying asleep, known as insomnia
• Excessive daytime sleepiness, known as hypersomnia
• Difficulty paying attention while awake
• Irritability

Over time, sleep apnea can have some potentially serious health consequences (like a higher risk of heart disease), so tell your doctor ASAP if you have any of the above sleep problems.

5. You deal with neuropathy (aka, nerve damage)

According to Dr. Kilkenny, chronically damaged nerves in your body (also known as neuropathy) can cause heat intolerance, sweating (or sometimes, not being able to sweat), and a burning sensation in your arms and legs.

Neuropathy symptoms can vary depending on the type of nerves that are affected, but other possible signs (along with heat intolerance) can include the following, per the Mayo Clinic:

• Gradual onset of numbness, prickling, or tingling in your feet or hands that can spread upward into your legs and arms
• Sharp, jabbing, throbbing, or burning pain
• Extreme sensitivity to touch
• Pain during activities that shouldn't cause pain, such as pain in your feet when putting weight on them or when they're under a blanket
• Lack of coordination and falling
• Muscle weakness
• Feeling as if you're wearing gloves or socks when you're not
• Inability to move (if motor nerves are affected)
• Bowel, bladder, or digestive problems
• Drops in blood pressure, causing dizziness or lightheadedness

In most cases, nerve damage is related to a health condition. Diabetes, autoimmune disorders, kidney disease, and long-term alcohol use can all cause neuropathy, along with burning and hot sensations, Dr. Kilkenny says.

Other medical problems like infections, tumors, bone marrow disorders, exposure to poisons, injury or pressure on the nerve, and low vitamin levels (among other things) can also lead to nerve damage, per the Mayo Clinic.

6. You have another underlying health condition

Besides neuropathy and sleep disorders like sleep apnea, a whole host of other health issues may make you more sensitive to heat. These include the following, per the NLM:

• Cystic fibrosis
• Diabetes
• Cardiovascular disease
• Graves' disease
• Mental illness
• Multiple sclerosis
• Obesity
• Too much thyroid hormone (thyrotoxicosis)
• Alcohol use
• Bacterial or viral infection
• Having had heat exhaustion or heat stroke before
• Illegal drug use (opioids, cocaine, methamphetamines)
• Lack of physical fitness
• Menopause
• Pregnancy

As mentioned earlier, certain medications can also cause heat intolerance. So if you’re taking a drug that raises your risk for overheating and you have one of the above medical issues, you can be hit with a double dose of heat sensitivity.

7. You're working up a sweat too close to bedtime

Any type of vigorous activity—from exercise to sex—can spike your body temperature, Dr. Kilkenny says. And if you build up a sweat right before you hit the hay, your body might need some time to cool down. Taking a cool shower may help lower your temp before going to sleep.

8. You drank caffeine too close to bedtime

We've all likely heard that drinking coffee too late in the day can be overstimulating and mess with your sleep that night. But turns out, a cup of joe close to bedtime can make you feel too hot to sleep.

Caffeine is a stimulant that can quicken your breathing, increase your heart rate, and raise your core body temperature, according to the Victorian Government Department of Health. Though the caffeine high typically hits between five and 30 minutes, these side effects can last up to 12 hours, depending on the person.

This heat sensitivity may be even more intense if you're going through menopause. In fact, a February 2015 study in ‌Menopause‌² found a connection between caffeine intake and a surge in night sweats (and hot flashes) in menopausal people.

Moral of the story: Cap your caffeinated beverages to earlier in the day if the stimulant is making you sweat at night.

9. It's your age

Another thing we attribute to aging? Overheating. According to the NLM, older adults (i.e., over the age of 65) have more difficulty regulating their body temperature. On top of this, we're more likely to have underlying health conditions or take meds that raise our heat intolerance as we age.Qt4rfe12

How to stay cool while you sleep

Staying cool is an important part of getting quality sleep at night and feeling the most refreshed when you wake up the next morning. Try out some of these tips from Dr. Kilkenny, to avoid waking up hot and sweaty:

• Wear light, breathable sleepwear: Materials like fleece, wool, and down can hold body heat, especially in summer months. Instead, stick to loose-fitting, breathable fabrics like cotton.
• Choose breathable bedding: Some pillow and mattress materials, like memory foam, can trap heat, which may be uncomfortable for hot sleepers. Instead, opt for pillows, sheets, and comforters that are lightweight, breathable, and moisture-wicking, and invest in a mattress that provides good airflow.
• Turn down the thermostat: Set the room temperature to 65 to 68 degrees Fahrenheit—i.e., the most comfortable temperature to sleep. On cooler evenings, open your windows for some cool fresh air.
• Use a fan: Still figuring out how to stop night sweats? A light breeze from a fan can help cool you off quickly.
• Consider a sleep divorce: We know this sounds harsh, but more couples are opting to sleep in separate bed, especially on very warm nights. This can help improve sleep quality if your partner's body heat, or other things like restlessness or snoring, are an issue.
• Stay hydrated: Your body needs water to generate sweat—i.e., your natural cooling system. While you may not want to chug water right before bed (you'll have to get up to pee), sipping throughout the day can help.
• Take a warm bath before bed: This jumpstarts the body’s process of vasodilation (i.e., widening of blood vessels), helping cool you down faster in preparation for sleep.
• Avoid foods and drinks that make you hot before bed: Carb-heavy meals, spicy foods, caffeine, and alcohol all have potential to increase your body temperature.

When to see a doctor

Occasionally overheating at night is often no big deal. It's usually from wearing thick pajamas or using too many blankets, and can be fixed by simply throwing off your covers or changing. But if you're waking up excessively hot on most nights and/or you get night sweats “severe enough to soak through your clothes and bedding,” it’s time to see your doctor, Dr. Kilkenny says.

According to Dr. Kilkenny, overheating and night sweats could be a sign of certain medical conditions including the following:

• Infectious diseases, including tuberculosis and HIV
• Various infections including endocarditis, the flu, and COVID-19
• Medical disorders such overactive thyroid and diabetes
• Neurologic disorders including autonomic dysreflexia and autonomic neuropathy
• Cancers including leukemia and lymphoma
• Behavioral health conditions including panic disorder and anxiety

Also, if you have sleep apnea symptoms (like snoring, restlessness, and daytime tiredness), see a sleep medicine doctor ASAP. Sleep apnea “can be a dangerous disorder that can [not only] disrupt sleep, but also dramatically increase the risk of heart disease,” Dr. Kilkenny says.

FAQ

Why do I get so hot at night as a female?

Hormones, hormones, hormones (most likely). “Many women experience night sweats and the feeling of being hot, especially at night, as part of premenstrual syndrome (PMS) as well as perimenopause,” Dr. Kilkenny says. He says this is due to fluctuations in estrogen and progesterone, which cause your hypothalamus—the part of the brain that controls body heat—to have trouble regulating your internal temp.

Put another way, hot flashes and night sweats are just your body’s way of trying to control your inner thermostat.

Another time you may be waking up hot at night? During pregnancy. “Pregnancy, especially in the first and third trimester, also leads to hormonal changes that regulate your body temperature,” Dr. Kilkenny says. “This can increase blood flow and raise your core body temperature, worsening the sensation of heat at night.”

Why do I feel feverish every night but don't have a fever?

Feeling feverish usually means you are hot, but have the chills. Sometimes heat sensitivity can make it feel like you have a fever when you don't. Maybe your mattress is trapping body heat or something you ate or drank is raising your internal thermostat.

It could also have something to do with your health. Anything from sleep apnea, nerve damage, hormones, or autoimmune issues can affect how your body regulates temperature. That said, if you feel feverish before bed more often than not, and it’s interrupting your sleep, see your doctor. They can examine you and run tests to help get to the bottom of the issue.

Why do I get so hot when I sleep even when it’s cold?

If you’re dripping with sweat even when your environment is comfortably cool for everyone else, you might be dealing with heat intolerance, aka, heat hypersensitivity. This happens when your body can’t control its temperature correctly or maintain a balance between cold and hot, according to Catholic Health.

Other common symptoms of heat intolerance include the following, per Catholic Health:

• Excessive fatigue
• Headaches
• Mood changes
• Muscle cramps or weakness
• Nausea and vomiting
• Rapid heartbeat
• Sweating too much or not at all

Heat intolerance is usually a sign of another underlying issue and can be caused by many things from old age to chronic medical conditions and certain medications. If it’s affecting your sleep (or quality of life in general), talk to your doctor. They can help get to the root cause of your heat intolerance and properly treat it.

—reviewed by Angela Holliday-Bell, MD