Night sweats are episodes of excessive perspiration that begin while a person is sleeping. Sweating is an important bodily function, helping to regulate body temperature, balance electrolytes, and keep the skin hydrated. But night sweats can be bothersome and uncomfortable.
Not all sweating during sleep is the same as having night sweats. Heavier sweating may be caused by a hot room or too much bedding, while night sweats can be caused by medication or a health condition.
Learning about the potential causes of night sweats and tips for coping with nighttime perspiration may help bring relief and more comfortable sleep.
What Causes Night Sweats?
There are many potential causes of night sweats, including certain medications, changes in hormone production, and medical conditions. Most people with night sweats do not have a serious disease.
When the body’s internal temperature increases, glands in the skin produce sweat in response. As sweat on the skin evaporates, it decreases the body’s temperature. Sweat is released in hot environments and during physical activity. Sweat can also be released when the body’s temperature rises in response to stress, fear, or anxiety.
Hyperhidrosis is the medical term used to describe sweating that exceeds what is needed to manage the body’s temperature. When hyperhidrosis occurs during sleep, it is referred to as night sweats.
Night sweats vary in severity from a light perspiration that may be unnoticable upon waking to a drenching sweat that soaks clothes and bedding.
Conditions That Can Cause Night Sweats
There are a wide range of conditions associated with night sweats. Night sweats don’t always have an underlying cause, but they can be triggered by fevers, changes in hormone levels, or other conditions.
Nearly any type of fever can lead to excessive sweating. Fever is when the body’s temperature is elevated by more than .5 degrees Fahrenheit above the normal core body temperature of 98.6 degrees as a result of an infection or other illness.
Body temperature often rises in response to infections. Many infections thrive at a person’s normal body temperature, so the body may develop a fever to combat the illness. Examples of types of infections that may cause night sweats include:
- Bacterial infections
- Viral infections, including COVID-19
- Fungal infections
- Parasitic infections, such as malaria and some tick-borne illnesses
Hyperthyroidism, also called an overactive thyroid, is a condition in which excessive thyroid hormone is made by the thyroid gland. Hyperthyroidism increases a person’s metabolism, which can cause the body’s temperature to go up and trigger excess sweating.
Diabetes can cause night sweats. In people with type 1 or type 2 diabetes, sweating can be triggered by low blood sugar, which activates the nervous system and causes symptoms like increased perspiration. A person with diabetes may also sweat after taking insulin or other drugs to manage blood sugar levels.
Nerve damage as a result of diabetes is another potential cause of night sweats. There are several types of nerve damage that can occur in people with diabetes, one of which is called autonomic neuropathy. Autonomic neuropathy describes nerve damage affecting internal organs, including parts of the digestive system, eyes, and even the sweat glands. Damage to these nerves can cause increased perspiration at night.
Other Hormonal Issues
The endocrine system includes several glands in the body that release hormones. Night sweats can be a symptom of many conditions that affect endocrine function. For instance, some tumors can cause changes in hormone levels. In addition, overproduction of growth hormone by the pituitary gland, known as acromegaly, can cause night sweats.
Some types of cancer can trigger night sweats. Lymphoma, kidney cancer, and prostate cancer are examples of kinds of cancer that may cause a person to experience excess sweating.
Night sweats can occur as a result of several conditions that affect the nervous system. The nervous system is composed of nerves originating in the brain and spinal cord that extend into the rest of the body.
Neurological conditions like stroke, Parkinson’s disease, and injuries of the spinal cord can cause night sweats. Excessive perspiration can also be a symptom of nerve damage or an overreaction of the nervous system to normal stimulation.
Night sweats are common in people with sleep disorders, though researchers are not sure if sleep disorders themselves cause night sweats.
For instance, as many as a third of people with obstructive sleep apnea (OSA) experience regular night sweats. OSA involves frequent interruptions in breathing during sleep, and the resulting drops in blood oxygen levels may induce night sweats.
Other Conditions Associated With Night Sweats
Numerous other health conditions are associated with night sweats, including:
What Medications Can Cause Night Sweats?
Night sweats are frequently caused by medications. Sweating at night is a side effect of many kinds of drugs including those that affect the sweat glands, the nervous system, or the regulation of body temperature.
- Antidepressants: Antidepressants are often linked to night sweats. Nearly all types of antidepressants have been associated with increased sweating, which usually begins within a few weeks of starting a new antidepressant drug.
- Methadone: Methadone, as well as several other prescription and illicit opioids, can cause a general increase in sweating.
- Hormonal medications: Medications that affects certain sex hormones, like estrogen and testosterone, may cause hot flashes and an overall increase sweating.
Other drugs associated with increased sweating include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, beta blockers, antihistamines, and cough suppressants.
If you are concerned that a prescribed medication may be causing your night sweats, please be sure to speak with a doctor before stopping the drug or changing your dose.
Causes of Night Sweats in Women
Night sweats in women and people assigned female at birth can be caused by hormonal changes during menstruation, pregnancy, and menopause.
Nighttime sweating can be a result of hot flashes. Hot flashes are common in people with premenstrual syndrome (PMS), a set of symptoms that occur in around 90% of women and people assigned female at birth.
PMS happens in the days or weeks before a menstrual period. Although the exact cause of PMS is unknown, researchers suspect that symptoms are triggered by changes in hormone levels.
Hot flashes and night sweats can also be a sign of a severe form of PMS called premenstrual dysphoric disorder (PMDD).
Hot flashes and night sweats may develop during pregnancy or after giving birth. These hot flashes are believed to be linked to the hormonal fluctuations that occur during and after pregnancy.
One study found that more than 30% of pregnant people experience hot flashes, which often reach their height during the third trimester. Around 25% of people continued to experience postpartum hot flashes that generally began to resolve after about two weeks.
Menopause describes the point one year after a person stops having menstrual periods. Symptoms such as changing periods, sleep difficulties, hot flashes, and night sweats commonly begin several years before a person’s final menstrual period, a time called perimenopause.
Hot flashes occur in up to 80% of people going through menopause. Researchers believe that hot flashes are a symptom of withdrawal from premenopausal levels of estrogens in the body. As a result of this withdrawal, the body initiates sweating at a lower temperature than it did before.
Causes of Night Sweats in Men
Night sweats in men and people assigned male at birth may be caused by low levels of testosterone.
Testosterone is a sex hormone that is mostly produced in the testicles in men and people assigned male at birth. Testosterone has many functions in the body, including fueling the development of muscles and bones and maintaining the production of red blood cells and sperm cells.
Without enough testosterone in the body, a person may experience symptoms like reduced sex drive and depression. If the level of testosterone falls quickly or to a very low level, it may trigger hot flashes and night sweats.
Testosterone levels naturally lower with age, but low testosterone can also develop due to certain health conditions or medical treatments. For example, several treatments for cancer can trigger night sweats, including hormone therapy for prostate cancer.
Other Reasons for Sweating at Night
While there are a range of medicines and health conditions that can cause night sweats, most people who sweat excessively at night do not have a serious underlying health condition.
In many cases, sweating at night is caused by keeping a bedroom above the ideal temperature, wearing too many layers of clothing to bed, being covered with excessive bedding, or regularly using tobacco, alcohol, or caffeine.
When to Get Help for Night Sweats
Anyone concerned about nighttime sweating should talk to their doctor. People should pay particular attention to symptoms that may signal an underlying health condition, including:
- Drenching night sweats that require changing bedding
- Night sweats occurring nightly or on a regular basis
- Sweats that have a noticeable hue or color
- Excess sweating that occurs along with other health issues, such as fever, unexpected weight loss, or exposure to COVID-19
Ways to Reduce Night Sweats
While night sweats cannot always be prevented, several steps may be helpful to reduce their frequency and impact.
- Talk to a doctor: The only way to learn the cause of night sweats is to talk to a doctor. A doctor can assess specific symptoms, suggest diagnostic testing, and provide treatment when appropriate.
- Review medications: Because several medications are linked to night sweats, consulting with a doctor can help identify any medications that could be increasing sweating. The doctor may be able to change the dose or find a new medication without this side effect.
- Wear baggy bedclothes: Many causes of night sweats are linked to an increase in body temperature. To reduce sweating, wear baggy, breathable clothing to bed.
- Improve airflow in the bedroom: Airflow can help sweat evaporate and cool down the body during sleep. Try opening doors and windows or using fans to enhance airflow in the bedroom.
- Cognitive behavioral therapy: Cognitive behavioral therapy (CBT) is a form of talk therapy that has been found to help decrease the symptoms of menopause and reduce hot flashes in people taking hormone therapy for prostate cancer.
- Find support: While emotional support cannot cure night sweats, it can help those experiencing the challenges caused by this symptom. Excessive sweating can affect sleep and other elements of day-to-day life, so consider talking to a counselor or other mental health professional for support.
Managing Menopausal Hot Flashes
For people in perimenopause, there are several additional tips that may be helpful for coping with night sweats and other menopausal symptoms.
- Ask about medicines: Although many people in perimenopause do not require treatment, those hoping to reduce hot flashes, night sweats, and other symptoms may find it beneficial to discuss hormone replacement therapy and other medical treatments with their doctor.
- Avoid triggers: Certain triggers can exacerbate menopausal symptoms. Staying away from things like spicy food, alcohol, coffee, and other sources of caffeine may be helpful.
- Try mind and body methods: Several mind-body practices have been found to help reduce the symptoms of menopause, including yoga, tai chi, acupuncture, and hypnosis.
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