Why Do You Sweat in Your Sleep? 11 Possible Reasons
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Medically reviewed by Valerie Cacho, MD
Occasionally sweating at night usually isn’t a cause for concern. If your bedding, pajamas, or the temperature outside is too warm, your body will sweat as a way to keep itself cool. It’s not uncommon to experience a night sweat episode. Data suggests night sweats may affect up to 41% of the adult population.
However, experiencing frequent night sweats that soak through your sleepwear, interrupt your sleep, or interfere with your daily functioning could be the result of an underlying health condition or medication side effect. If you experience regular heavy night sweats, you may want to see a healthcare provider to determine the root cause.
Related: What Is Sweating and Why Do We Do It?
Sleeping Environment
One of the more obvious causes of nighttime sweatiness is that the environment you're sleeping in is too warm. Experts generally suggest an ideal sleeping temperature is around 65 degrees, but this number can vary slightly based on preference and other factors.
Your body goes through normal temperature changes as you sleep. During points of the night when your body temperature rises, being in a warm environment can cause you to wake up in a sweat. So while wearing long-sleeve pajamas with layers of heavy bedding might feel cozy as you’re falling asleep, that extra warmth may become too hot later in the night.
Infections
Any type of infection that causes a high fever can make you sweat—even in your sleep. Fevers happen when your body is trying to kill off the virus, bacteria, or other organism that’s causing the infection. The rise in body temperature creates a harsher environment for these organisms, making it more difficult for them to survive.
Types of infections that induce night sweats could range from serious infections like HIV, mononucleosis, or pneumonia, to more common viruses like the flu or Covid-19.
If an infection is the reason for your night sweat reaction, you may also experience chills, shortness of breath, pain, vomiting, and other related symptoms.
Hormone Levels
Hormone levels can fluctuate during states of pregnancy, childbirth, and menopause; these hormone imbalances can lead to night sweats.
Too much or too little of certain hormones can throw off the way these chemical messengers regulate body functions—including your internal temperature control. Hormone therapy can prompt this reaction, too.
If hormone imbalances are the cause of your night sweats, you may also experience other symptoms like hot flashes during the daytime, menstrual irregularities, trouble sleeping, and more.
Endocrine Disorders
Conditions that impact the body’s endocrine system—like hyperthyroidism and diabetes—can also throw hormone levels off-kilter, which may sometimes result in night sweats.
In people with diabetes, blood sugar levels can dip low during the night. This is known as hypoglycemia, and often leads to sweating more than normal overnight. In these cases, you'd likely also experience other common diabetes symptoms such as increased thirst and urination.
In conditions like hyperthyroidism, the thyroid hormones become overactive and certain bodily functions may be sped up—including sweat production. Increased overnight sweating might accompany other hyperthyroid-related symptoms like weight loss, nervousness, and fatigue.
Medications
A variety of over-the-counter (OTC) and prescription medications can prompt night sweats. Certain classes of drugs may interact with the part of the brain that controls your internal temperature, or they may have an affect on the nervous system—leading to increased sweat production.
Common drugs that can cause increased sweating include:
Prescription pain medications
Heart and blood pressure drugs
Antidepressants
Thyroid medications
Decongestants
If night sweats are a side effect of a particular drug you are taking, make sure to check with a healthcare provider before abruptly discontinuing any medications.
Hyperhidrosis
Hyperhidrosis is a condition that causes excessive sweating—day or night. If you have hyperhidrosis, you may notice excess sweatiness on certain parts of the body, such as the palms, underarms, feet, or head, or you could notice increased perspiration all over.
This increased sweating happens without any apparent environmental or emotional triggers. However, in some cases, hyperhidrosis can be the result of another medical condition like lung disease, Parkinson's disease, stroke, and more.
Sleep Disorders
Research has linked some sleep disorders to night sweats, though the exact reasons aren’t completely known.
For example, night sweats appear to be more common in people with conditions like obstructive sleep apnea and insomnia. This may be due to the way frequent night awakenings arouse the body. In some studied cases, when sleep apnea was treated, the night sweats diminished.
Depending on the exact type of sleep disorder, you’d also notice symptoms like trouble falling and staying asleep, snoring loudly or gasping for periods throughout the night, frequent daytime sleepiness, and more.
Anxiety and Stress
The symptoms of experiencing an anxiety disorder or chronic stress aren't just mental—they can be physical, too. Anxiety and stress can lead to night sweats as the body amps up some of its responses and functions—including sweat production.
Depending on the underlying cause of your anxiety, stress, or other related condition, you may also experience symptoms like a fast heartbeat, rapid breathing, shakiness, and more.
Substance Use
Regularly consuming alcohol or smoking can trigger excess perspiration due to the substances' impact on the body's central nervous and circulatory systems.
Depending on how your body reacts to drinking or smoking, your internal temperature can be affected and you may experience extra sweating the night after partaking in consumption. Along with night sweats, typical hangover-related symptoms such as headache, nausea, and fatigue may also be present the next day.
Cancer
Although a more rare reason for experiencing night sweats, certain types of cancer can prompt nighttime sweatiness.
In particular, research shows Hodgkin’s lymphoma can cause night sweats. With this condition, you’d likely experience other cancer symptoms like unexplained weight loss and fever.
GERD
Gastroesophageal reflux disease (GERD) is a condition that manifests when stomach acid creeps back up into your esophagus. Experts aren’t sure of the exact link, but sweating in your sleep appears to be related to this condition.
Along with related symptoms like heartburn, chest pain, a hoarse voice, and vomiting—waking up with a bitter taste in your mouth has also been reported in GERD patients who experience night sweats.
How to Stop Sweating at Night
Making some changes to your bedtime environment and your daily routine could help prevent or manage night sweats for a better night’s sleep. Here are a few places to start:
Keep your bedroom cool: Set the temperature to around 68 degrees, if comfortable for you.
Switch up your bedding and sleepwear: Choose lighter, moisture-wicking layers to allow for some temperature flexibility.
Exercise regularly: This will help regulate body temperature and circulation, but make sure to not workout too close to bedtime.
Eat a healthful diet: Eating plenty of fruits, vegetables, lean proteins, whole grains, and healthy fats can help balance hormone levels and potentially lower the chances of developing night sweats.
Manage stress: Practice meditation, breathwork, yoga, or other relaxation techniques to keep the nervous system balanced and steer clear of episodes that could trigger night sweats.
Avoid alcohol, caffeine, spicy foods, and other substances: These can all increase internal body functions, especially when consumed too close to bedtime.
When to See a Healthcare Provider
Occasional night sweats are common and can happen to anyone. However, if you’re finding that night sweats are impacting your quality of life—and ability to get some zzz’s—it might be time to have this issue checked out. Contact a healthcare provider if your night sweats are:
Frequent or extreme
Interfering with your sleep
Impacting your daytime functioning
Not explained by a medical condition or medication side effect
Accompanied by weight loss or chest pain
In the meantime, consider keeping track of nighttime sweat triggers that your healthcare provider may ask you about, including:
Sleeping patterns and bedtime routines
Stress levels
Diet
Daily activities and exercise
Any medications you may be taking
Any additional symptoms that accompany the night sweats
Pending the answers to those questions and a physical exam, your healthcare provider might order blood tests to check for any disease abnormalities or infections, or a hormone test to check for any imbalances.
A Quick Review
Waking up covered in sweat can be a sign that your sleeping environment is too warm—or it could be a red flag for another issue, like an underlying health condition or medication side effect. A few lifestyle and sleep routine changes may help get this under control. If frequent night sweats are disrupting your sleep and interfering with your daily life, a healthcare provider can help get to the root cause and offer treatment if necessary.
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