What Causes Night Sweats & How to Stop Them

By: SleepScore Labs  |  May 11th, 2021

When is the last time you woke up in the middle of the night drenched and soaking in sweat? This overnight perspiration may have been so severe that you needed to change your clothes, or even your sheets. For many, these night sweats can contribute to poor sleep quality and hinder your ability to perform at your peak during the day. In this article, we’ll explore the potential causes of night sweats, when it may be a good idea to reach out to a doctor, and sleep hygiene tips that may help support healthy overnight temperature and sleep-wake patterns.

What Are Night Sweats?

Night sweats, medically known as nocturnal hyperhidrosis, is the repeated occurrence of excessive sweating during sleep usually related to an underlying medical illness or condition. Night sweats are technically different from feelings of overheating resulting from environmental factors like bedroom temperature or heavy bedding. When experiencing night sweats, simply lowering the temperature and removing your comforter may not always cut it.

Night sweating is also distinct from hot flashes which are sudden periods of intense heat occurring during any time of the day. Hot flashes may be classified as night sweats if they happen in the middle of the night and regularly incite excessive overnight sweating. Night sweats are also different than skin blushing or “flushing”. Flushing is a sudden reddening of the upper chest and face area resulting from increased blood flow. Unlike night sweats, periods of flushing do not usually cause intense sweating.

Night sweats are surprisingly common yet under-reported. Researchers estimate that night sweats occur in approximately 10 to 40 percent of people – with 23 percent experiencing pure night sweats, and 18 percent having both night and day sweating. A 2002 study by University of Oklahoma researchers found that the prevalence of night sweats was highest in people aged 41 to 55 years old. Unfortunately, even when night sweats were severe, a majority of patients in this study did not report their symptoms to their physicians.

What Causes Sweating in Sleep?

The body’s internal temperature regulator – a process known as thermoregulation – allows us to maintain optimal core body temperature. These mechanisms help by returning you to a state of homeostasis, or equilibrium. These thermoregulatory processes are incredibly complex and often influenced by many factors. As a result, identifying one underlying cause of night sweats can be difficult without the help of a doctor. Night sweats may be related to sleep conditions and other health problems. You should talk to your doctor if your night sweats are frequent, persistent over time, severe enough to affect your daytime life, or accompanied by other health problems. In this article, we’ll explore five common causes of night sweats.

  1. Menopause

Menopause is a time of natural menstrual cycle changes that usually occurs between 45 and 55 years of age. During menopause, significant hormonal changes to estrogen and progesterone may affect certain thermoregulatory processes causing hot flashes in approximately 85 percent of women. Menopausal hot flashes cause temporary sensations of heat, sweating, flushing, anxiety and chills that last between 1 to 5 minutes. Studies have shown that severe hot flashes are often associated with chronic insomnia. For example, researchers from Stanford University found that more than 50 percent of perimenopausal and postmenopausal reported chronic insomnia symptoms. Menopausal hot flashes occurring at night can provoke night sweats and, not surprisingly, may contribute to poor sleep quality and sleep-wake problems.

  1. Hormonal Disorders

The endocrine system comprises of a range of glands that are responsible for producing and secreting hormones. Changes to the endocrine system resulting in hormonal problems may be related to night sweats. Examples of medical conditions and hormonal problems that are associated with night sweats include:

  • Hyperthyroidism (overactive thyroids)
  • Diabetes (and elevated blood sugar)
  • Endocrine tumors (adrenal gland tumors and carcinoid syndromes)
  • Orchiectomy (testicular removal)
  • Ovarian failure
  1. Infection and Immune Responses

Infections that result in fever, chills, fatigue, and malaise may also be associated with night sweats. Excessive overnight sweating likely occurs if an infection triggers a fever. Several specific infections are thought to be risk factors for night sweats including: human immunodeficiency virus (HIV), tuberculosis, fungal infections, endocarditis (inflammation of the heart’s lining), and other infections.

  1. Medications

Several medications and drugs are known to have side effects associated with night sweats. These medications include:

  • Antipyretics including acetaminophen used to lower fevers
  • Antihypertensives used to treat high blood pressure
  • Phenothiazines used to treat psychotic disorders

Excessive caffeine too close to bedtime can also cause generalized sweating. Lastly, substance abuse – especially alcohol and heroin – can increase the risk of developing night sweats.

  1. Obstructive Sleep Apnea

Night sweats are a common symptom of obstructive sleep apnea. A 2013 study found that frequent overnight sweating (more than 3 times per week) was reported in up to 33 percent of patients with obstructive sleep apnea relative to just 12 percent of the general population. In patients who successfully treated their sleep apnea using positive airway pressure, the prevalence of night sweats dropped to 11 percent. Obstructive sleep apnea is a common but debilitating sleep disorder that goes largely undiagnosed. It’s important to speak to your doctor if, in addition to night sweats, you experience the following after unrefreshing sleep:

  • Constant tiredness
  • Poor concentration
  • Morning headaches
  • Depressed mood
  • Night sweats
  • Weight gain
  • Lack of energy
  • Forgetfulness
  • Sexual dysfunction
  • Frequent urination at night

How to Treat Night Sweats

It’s important to remember that frequent night sweats may be a sign of an underlying illness or condition that warrants a doctor’s visit. As discussed, there are many potential causes of night sweats. Ruling out more serious conditions can help your doctor find a treatment option that works best for you. Potential treatment methods may include changes to your environment, medication, or behavioral therapies.

Keeping your bedroom cool and comfortable may help you comfortably sleep through the night. Here are some healthy sleep tips that are part of a regimen of sleep hygiene to support your sleep:

  1. Keep your bedroom temperature cool: Although the recommended sleeping room temperature range is between 60 and 67 degrees, it’s important to remember that the right temperature for you is likely unique. If you frequently wake up too cold or too hot, adjust the thermostat accordingly.
  2. Use breathable bedding: Consider using a lighter mattress and sheets that can help disperse heat. Certain mattress pads like the ChiliPad Sleep System can also support sleep by allowing you to set the mattress in one-degree increments from 55° – 110° F.
  3. Limit caffeine and alcohol consumption: For many people, a major step in sleep improvement is identifying sources of caffeine and then reducing caffeine consumption, particularly later in the day. Alcohol can also spike body temperature and induce sweating. Limiting caffeine and alcohol consumption (especially in the evening) may help reduce night sweats.
  4. Relax and unwind: Several studies have found that relaxation-based methods using controlled breathing techniques can help reduce hot flashes by up to 50 percent. In addition to reducing hot flashes, relaxation techniques can help with falling asleep.

SleepScore Labs Solutions

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Sleep well!


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