6 most common cause(s)
Night sweats are when you sweat while you’re asleep. They are fairly common, with one review in the Journal of the American Board of Family Medicine reporting that anywhere from 10% to 41% of people may get them. They are more common in women, often triggered by hormonal changes that occur before and during menopause. But they can also happen in men who have low testosterone.
In both men and women, night sweats may be caused by increased levels of certain neurotransmitters, infections, hyperthyroidism, low blood sugar, or cancer. Often the exact reason for night sweats is not clear. Sometimes it’s caused by a blanket that’s too heavy or a bedroom that’s too hot for sleeping. Night sweats can lead to poor sleep and leave you feeling tired during the day, so it’s important to try to figure out the cause.
What night sweats feels like
Most people notice they have night sweats because they wake up with wet pajamas, sheets, and blankets. Night sweats can range from mild, where you may be just a little damp, to severe, where you wake up drenched in sweat.
Depending on the cause, they may be as brief as 30 seconds or last up to 10 minutes. Some people will have just one episode of sweating during the night and others may have them more often. They may occur every day, every few days, once in a while, or rarely. When they are frequent, they can interfere with sleep and affect your quality of life.
Night sweats in men
Night sweats are less common in men. Low testosterone, also known as male hypogonadism, can cause night sweats in men. Obstructive sleep apnea occurs more often in men and can also cause night sweats. Additionally, some cancers that cause night sweats, such as certain lymphomas and leukemias, are more common in men, according to the Leukemia & Lymphoma Society.
When to worry about night sweats
Night sweats may be a sign of a serious underlying medical condition, like cancer. If you have any of these other symptoms, you should see your doctor:
- Unexplained weight loss
- Fever
- Fatigue
- Weakness
- Easy bleeding or bruising
- Swollen lymph nodes
- Frequent infections
- Pain
- Headaches
- Nausea and vomiting
- Confusion
- Seizures
When should I be concerned about night sweats?
“If your night sweats improve simply by changing your bedding or the temperature in the room, chances are it is not due to a serious medical problem. If you are still experiencing night sweats, “Do I need blood work?” is an important question to ask your doctor. Sometimes blood work is needed to evaluate for diseases like hyperthyroidism, cancers, diabetes, and infections.”—Dr. Elizabeth Grand
Common causes of night sweats
1 . Menopause & perimenopause
Menopause refers to the end of a woman’s reproductive cycles. The official date of menopause is when a woman has not had a period for at least one year. The time when your body is transitioning to menopause, when a woman’s ovaries start to produce less and less estrogen, is called perimenopause. This phase lasts an average of 4 years.
It is thought that low estrogen levels influence the body’s thermostat to become more sensitive to changes in temperature.
Common: Women experience menopause usually between ages 45 and 55 with the average age being 51 years old. [Source: National Institutes of Health]
Co-occurring symptoms
- Hot flashes
- Vaginal dryness
- Irregular periods
- Mood changes
- Weight gain
- Dry hair
- Dry skin
Treatment and urgency: See your primary care doctor or a gynecologist if night sweats bother you or affect your quality of life, or you have other symptoms related to menopause that you want to treat.
There are medications available that can help reduce your symptoms. Hormone therapy, antidepressants, gabapentin, and clonidine may be prescribed to reduce hot flashes and night sweats caused by menopause.
2. Infections
Infections often cause fevers, which can make you feel hot and sometimes sweaty. But there are several infections that specifically cause night sweats. These include tuberculosis, HIV, endocarditis (infection of the heart valves), and osteomyelitis (bone infection).
Uncommon: Tuberculosis is rare, with only 7,163 cases reported in the entire U.S. in 2020 [source: CDC]. In 2019, there were 36,801 new cases of HIV in the U.S. [Source: CDC].
Co-occurring symptoms:
Treatment and urgency: If you suspect you have an infection, call your doctor right away. They may tell you to go to an emergency room, as some infections that cause night sweats require treatment in the hospital. Endocarditis and osteomyelitis are very serious infections and usually need to be treated with IV antibiotics.
If you have a less urgent bacterial infection, you will be given antibiotics. Tuberculosis is usually treated with a combination of antibiotic pills. HIV is treated with oral antiviral medications.
3. Hyperthyroidism
The thyroid gland is responsible for producing thyroid hormones, which regulate the body’s metabolism. Hyperthyroidism is when the thyroid produces too much hormone, revving up your metabolism. The most common cause of hyperthyroidism is an autoimmune condition called Graves disease.
Uncommon: Graves disease affects 1 in 200 people in the U.S. [Source: National Institutes of Health].
Co-occurring symptoms
- Palpitations
- Weight loss
- Tremor
- Difficulty sleeping
- Anxiety
- Irregular or loss of periods
- Dry hair and skin
Treatment and urgency: Talk to your doctor, who may refer you to an endocrinologist, a doctor that specializes in hormonal conditions. Graves disease is treated with antithyroid medications, such as methimazole and propylthiouracil, and radioactive iodine therapy.
If your hyperthyroidism is due to a specific thyroid nodule or nodules, you may need surgery to remove the nodule or entire thyroid.
Night sweats and diabetes
“If you have diabetes and are experiencing night sweats, you should tell your doctor what your daily activities are like, especially during the period of time before you go to sleep. Things like changes in exercise habits, eating schedule, alcohol consumption, and timing of diabetes medications can all result in nocturnal hypoglycemia that leads to night sweats.”—Dr. Grand
4. Low blood sugar at night
If your blood sugar (also known as glucose) drops during the night, it can cause night sweats. This is known as nocturnal hypoglycemia. Very low blood sugar triggers our “fight or flight” response, which increases levels of adrenaline. That, in turn, can cause sweating, palpitations, tremors, and anxiety.
Certain diabetes medications can cause low blood sugar. It can also occur when a diabetic person misses their evening meal or exercises before bedtime. Additionally, alcohol can cause low blood sugar in people with and without diabetes.
Common in people with type 1 diabetes: About half of severe hypoglycemic episodes occur during sleep [Source: Endocrine Practice].
Co-occurring symptoms
- Palpitations
- Shaking
- Confusion
- Dizziness
- Fainting
- Seizure
Treatment and urgency: The treatment for nocturnal hypoglycemia is to eat or drink something with sugar, usually by having a small amount of fruit juice or candy, or a glucose tablet. Even if your symptoms are mild and you feel better right away, you should still call your doctor, especially if your glucose number is less than 70.
If you are taking diabetes medications, your doctor may need to adjust the dose or type of medicine to prevent hypoglycemia from reoccurring. If nocturnal hypoglycemia is severe, some people may be unconscious or in-and-out of consciousness. When this happens, call 911, and do not try to give them sugar by placing food or drink in their mouths—they could choke on it.
5. Cancers
Blood cancers like leukemia and lymphoma may cause night sweats. These cancers involve the overproduction of certain types of blood cells. It is not well understood why they cause night sweats, but theories include increased susceptibility to infections and increased inflammation in the body. Other types of cancers that may cause night sweats include prostate cancers, kidney cancers, and carcinoid tumors.
Uncommon: Almost 40% of people with a type of leukemia called chronic myeloid leukemia report night sweats, and 30% of people with Hodgkin lymphoma do [Source: Journal of the American Board of Family Medicine].
Co-occurring symptoms
- Weight loss
- Decreased appetite
- Easy bleeding or bruising
- Dizziness
- Lightheadedness
- Fainting
- Palpitations
- Headaches
- Swollen lymph nodes
Treatment and urgency: See a doctor right away if you have these symptoms. You may be referred to an oncologist (cancer specialist). Leukemia and lymphoma are typically treated with chemotherapy. Radiation therapy may also be a part of treatment, in particular if the leukemia or lymphoma has spread throughout the body. A bone marrow transplant may also be recommended.
6. Medications
There are several medications that may cause night sweats as a side effect. Some of the most commonly prescribed ones include:
- Antidepressants. These typically increase levels of the neurotransmitter serotonin, which can affect body temperature regulation. When levels of serotonin increase, some people experience excessive sweating at night and during the day. Night sweats have been reported with SSRIs (selective serotonin reuptake inhibitors), tricyclic antidepressants, and Wellbutrin.
- Diabetes medications. These lower blood glucose levels, but if levels get too low, it can cause hypoglycemia. Symptoms of hypoglycemia include dizziness, lightheadedness, palpitations, shaking, sweating, and passing out. Certain classes of diabetes medications have a higher risk of hypoglycemia including sulfonylureas (i.e., glyburide), meglitinides (i.e., repaglinide), and insulin.
- Anti-estrogen medications. Raloxifene, which is used to treat certain types of breast cancer, may cause night sweats. Leuprolide, used to treat prostate cancer, certain breast cancers, and endometriosis, and used in transgender hormone therapy, reduces sex hormone levels and can cause night sweats.
Do SSRIs cause night sweats?
“It has been reported that an estimated 7–19% of people on SSRIs experience night sweats. If you are experiencing night sweats and on an SSRI, talk to your doctor about whether this is a potential side effect. “—Dr. Grand
7. Idiopathic hyperhidrosis
- Excessive sweating during the day
- Night sweats
- Moisture stains on clothing
- Itching
- Strong body odor
Hyperhidrosis is the medical term for excessive sweating. When something is idiopathic, it means that the cause is unknown. People with idiopathic hyperhidrosis experience excessive sweating both during the day and while sleeping. The sweating can be limited to certain areas of the body like palms and soles or over the entire body.
Uncommon
Co-occurring symptoms
- Excessive sweating during the day
- Itching
- Strong body odor
Treatment and urgency: Excessive sweating is usually treated with an aluminum-based prescription deodorant, which works by blocking sweat glands. Another option is an anti-moisture cream containing glycopyrrolate, which also reduces sweating. Oral medications such as oxybutynin and benztropine may also be prescribed.
A procedure called iontophoresis is used for excessive sweating on hands and feet. A small electrical current is passed through water and delivered to the skin, which is thought to reduce the activity of sweat glands or block the ducts.
Botox injections into the affected areas, such as armpits, also help reduce sweating. If none of these options work, or if the hyperhidrosis is severe, surgery to either remove sweat glands or cut certain nerves related to sweating may be recommended.
How to stop night sweats
The first step in reducing night sweats is to identify the cause.
- If you have a fever, contact your doctor to see if you need to be tested for an infection.
- Check your bedding. Your blankets may be too warm for your room. Use lighter-weight bedding to see if that helps.
- Wear lighter or moisture-wicking clothing at night.
- If night sweats do not improve, or you are concerned that you have an underlying health problem, call your doctor.
FAQs about night sweats
Here are some frequently asked questions about night sweats.
Why do I have night sweats after drinking alcohol?
When you drink large amounts of alcohol, it may cause your blood vessels—especially the blood vessels near your skin—to dilate. This causes the reddening or flushing effect that happens when someone drinks a lot or they are intolerant of alcohol. The dilation of blood vessels near the skin can cause flushing and sweating. Additionally, alcohol can lower your blood sugar level, which can also cause night sweats if you drink before you go to bed.
Can stress and anxiety cause night sweats?
Yes, stress and anxiety can cause sweating at any time if it is severe enough. It usually does not cause sweating, however, while you are sleeping. A night terror or nightmare can cause increased stress hormones and sweating. Medications used to treat anxiety, such as SSRIs, can also cause night sweats.
How long do menopause-related night sweats last?
Menopause-related night sweats may last for years, though they may decrease in frequency over that time. Women experience night sweats and hot flashes during perimenopause and menopause an average of 7 years, according to a study in JAMA Internal Medicine.
Why do I suddenly have night sweats?
Sudden night sweats are most often a sign of a change in bedding or atmosphere at night, such as bedsheets being too heavy or temperature being too warm. It can be unsettling to wake up with night sweats. Check if a bed partner is having the same symptoms. If so, it is likely from something related to your sleeping environment.
However, ongoing and severe night sweats with no explanation can be a sign of something very serious and should be evaluated, especially if you also have dizziness, fatigue, pain, change in vision or mental status, weight loss, or easy bleeding or bruising.
Why do my night sweats come and go?
Night sweats most often come and go with bed habits. For example, the heat of the room or the amount of bedding may play a role in night sweats. Low-grade infections, hormonal changes, and medications may also cause night sweats.
Night sweats may not mean anything serious, and often are from environmental changes and not bodily changes. They are usually only worrisome if they continue for a prolonged period of time or you have other new symptoms.
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