When you hear about night sweats, you probably think: menopause. It’s true that the menopausal transition is often accompanied by night sweats that significantly affect sleep.
But hyperhidrosis—that’s the medical term for excessive sweating—can happen to anyone, adults and children, and for a variety of reasons. And hyperhidrosis that occurs at night often spells trouble for sleep.
Estimates vary, but research indicates that as much as 12% or more of the general population may experience night sweats. And the prevalence of night sweats increases with age. Among older adults, research shows nighttime sweating is more frequent. One study found that more than 40% of adults over age 64 had at least one episode of night sweats within the past month. I’ve seen patients of all ages and genders contend with nighttime sweating that creates restless, interrupted sleep.
Maybe it’s because of embarrassment, or maybe it seems like not a big deal, but hyperhidrosis is a condition that often gets overlooked. Research indicates that fewer than 4 in 10 people speak with their physicians about excessive sweating. Although most people with this condition don’t seek treatment, for many of them, the condition is debilitating. About one-third of people with hyperhidrosis say the condition is barely tolerable or intolerable, and it regularly interferes with their daily lives, according to research.
Before we look at the impact on sleep, here are a few things to know about hyperhidrosis and sleep hyperhidrosis (aka night sweats):
Hyperhidrosis involves sweating that doesn’t necessarily—or even often—relate to heat in the environment or to vigorous physical activity, two of the reasons we commonly see sweat appear. (To be clear, sweat from steamy weather and from exertion can themselves interfere with sleep.)
Hyperhidrosis comes in a couple of forms. Primary focal hyperhidrosis is excessive sweating that has no underlying medical cause. With this form of hyperhidrosis, the nervous system appears to over-signal sweat glands to produce. There seems to be a strong genetic component for primary focal hyperhidrosis. Studies suggest that there’s a family connection in 65% of cases.
Primary hyperhidrosis often occurs in specific areas across the body: the hands, the feet, the face. Many people experience this form of hyperhidrosis in more than one part of the body at the same time.
Secondary hyperhidrosis is sweating that is connected to a medical condition.
Sweating from secondary hyperhidrosis tends to be pervasive throughout the body, rather than localized.
Both primary and secondary hyperhidrosis can interfere with good sleep.
Some of the conditions that come with secondary hyperhidrosis as a symptom include menopause, thyroid disorders, heart conditions, sleep disorders, diabetes, and infection, all of which can come with sleep problems. I’ll talk more in depth about how sweat from these conditions affects sleep in a minute.
Excessive sweating can also be a side effect of medication. Medications that can cause hyperhidrosis include:
medication for GERD
drugs that treat glaucoma
medications that treat neurological diseases such as Alzheimer’s and Parkinson’s
Some cancer drugs
It takes an average of about 9 years for people to seek medical assistance for excessive sweating. That’s a long time during which sleep can be disrupted, while restlessly sweating at night. It’s also a long time for conditions that produce hyperhidrosis to go untreated, along with your restless, unrefreshing sleep.
How night sweats affect sleep and health
Sleep hyperhidrosis can do a number on your sleep, diminishing sleep quality and lowering your amount of nighttime rest. Sweating at night makes it harder to fall asleep and more likely you’ll wake throughout the night, leaving you feeling tired, low energy, and fatigued during the day.
The consequences of night sweats go beyond sleep loss. Recent research show that the sleep loss from night sweats has a negative impact on mood: there’s a strong association between depressed mood and night sweats that scientists pinpointed to the sleep problems that arise from sweating. There’s also research indicating that night sweats are linked to increased risk for cardiovascular disease. Several studies have pointed to this connection between night sweats and heart disease risk. Many of those studies involve women in stages of menopause. It’s important that we see those studies continue, and broaden to include other populations, to evaluate the relationship between sleep hyperhidrosis and cardiovascular disease risk.
Here’s another important dimension of night sweats that shouldn’t be overlooked. Night sweats can make sleeping with a bed partner difficult and put real stress on relationships. Discomfort, embarrassment, and trouble sleeping come together in a difficult mix for couples. It’s common for people who experiencing nighttime sweating to be uncomfortable sleeping close to another person. And sleeping next to a person with night sweats can disrupt partners’ sleep.
Conditions linked to night sweats
Obstructive sleep apnea. It might surprise you to hear that sleep apnea is strongly associated with night sweats. A recent study found people with untreated sleep apnea are about three times as likely as the general population to experience excessive sweating at night. This study found about a third of men and women with OSA had night sweats three or more times a week. The good news? According to research, treating sleep apnea with CPAP reduced the prevalence of night sweats in people with OSA to about the same levels as the overall population. If you’re experiencing night sweats, consider the possibility that this sweating is a sign of sleep apnea—and talk with your physician about an evaluation.
Hormone imbalances, including thyroid disorders and low sex hormones. The hypothalamus is the part of the brain that regulates body temperature. More broadly, this area of the brain is responsible for maintaining homeostasis, or internal balance. The hypothalamus regulates the production and release of hormones. (It’s also directly involved in regulating sleep cycles.) Hormone imbalances often go hand in hand with irregular, excessive sweating. One of the most common hormone irregularities linked to night sweats is an overactive thyroid, a condition known as hyperthyroidism. When hyperthyroidism occurs, the thyroid gland over-produces its hormone, thyroxine, leading to an overstimulation of the nervous system and a series of arousal-based symptoms, including nervousness and anxiety, irregular heartbeat, weight loss—and excessive sweating, both during the day and at night. According to research, people with hyperthyroidism have particular difficulty falling asleep and maintaining sleep throughout the night. In many cases, I will check for hyperthyroidism when evaluating someone with insomnia.
Other hormone imbalances that lead to night sweats include the low and fluctuating estrogen levels of menopause (more on that in a minute), and low testosterone in men. Testosterone declines naturally in men with age. We know that night sweats become more common in older adults. Medical conditions, including infection and injury to testes, metabolic disorders, inflammatory diseases and medications such as steroids and hormone therapy to treat cancer, are other causes of low testosterone that may lead to sleep hyperhidrosis.
Excessive adrenaline in the system can cause hyperhidrosis. Adrenaline is part of the body’s stress response, and stress is another reason behind sweating uncomfortably at night.
Low blood sugar. Night sweats often accompany hypoglycemia, or low blood glucose. Low blood sugar interferes with the activity of the nervous system, and its role in regulating body temperature and sweating. Night sweats are a common symptom of diabetes.
Cancer. Sweating at night can be a symptom of cancer. Night sweats are also one common side effect of both chemotherapy and radiation. These common cancer treatments also may trigger the onset of other medical conditions, such as hypothyroidism, alterations to mood and stress levels, and changes to hormone levels, all of which can cause sweating at night. Drugs used in cancer treatment, including hormone therapy medications, steroids, pain relievers, and antidepressant medications can also induce night sweats.
Infection. Night sweats frequently occur when the body is fighting infection, often accompanied by fever. Feeling unwell and experiencing night sweats can be a sign of the presence of infection.
GERD. Gastroesophageal reflux disease, GERD, or chronic acid reflux, is another cause of night sweats that surprises people. GERD has serious negative consequences for sleep. Because of lying down in bed, symptoms of GERD are often at their worst at night, as stomach acid rises through the esophagus and burns the back of the throat, making it difficult to fall asleep and keeping people in light, restless sleep. There’s also a large overlap between GERD and sleep apnea. Research suggests that roughly 60% of people with OSA also have GERD. Night sweats are another, lesser known symptom of GERD that can interrupt sleep and reduce its quality.
Menopause. In menopause, night sweats are one of the body’s responses to drops in estrogen. Many women start to experience night sweats during perimenopause, and uncomfortable, sleep disruptive sweating at night often increases in frequency until a woman reaches a couple years’ post-menopause, at which point night sweats tend to diminish.
Obstructive sleep apnea becomes common in women as they age. By menopause, a woman’s risk for OSA is about equal to a man’s risk. Recent studies show a link between hot flashes and obstructive sleep apnea in menopausal women. According to the research, women with severe hot flashes during the day or night may be at significantly higher risk for obstructive sleep apnea than women who experience mild hot flashes, or none at all.
What you can do about night sweats
You know what I’m going to tell you first and foremost: talk with your physician. Excessive sweating, day or night, is an uncomfortable, disruptive problem that warrants your—and your doctor’s—attention. The associated sleep problems that come with hyperhidrosis also need to be addressed, to avoid the long-term consequences to health, performance and emotional well being that come from chronically disrupted sleep.
Wear light breathable fabrics to bed. Or sleep nude. When picking your pajamas, steer clear of synthetic fabrics that trap heat. Opt for cotton instead. Sleep in as little clothing as is comfortable for you—and try sleeping in the nude.
Select natural, non-synthetic bedding. Cotton sheets and blankets won’t trap heat the way polyester does. That super-soft microfleece blanket that keeps you warm may be keeping you too warm. Layer your bedding so it’s easy to remove a blanket to keep things cool.
Avoid heat-trapping memory foam. Pillows and mattresses made from memory foam create heat surrounding your body, which may exacerbate nighttime sweating.
Actively cool yourself during sleep. I recommend the Chilipad to my patients—it’s a mattress topper that enables you to exert control over your body temperature during sleep, to avoid being too hot (or too cold).
Nighttime sweating shouldn’t be ignored. Get to the bottom of your hyperhidrosis, find out whether there’s an underlying medical issue that’s causing it, and you’ll both feel better and improve your nightly rest.
Michael J. Breus, PhD
The Sleep Doctor™
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