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Why do I wake up in the middle of the night sweating?

Waking up drenched in sweat in the middle of the night can be alarming. Known as “night sweats”, this phenomenon affects people of all ages and has a variety of potential causes.

What are night sweats?

Night sweats refer to episodes of extreme sweating that occur during sleep. They result in nightclothes and bedding being soaked with sweat. Night sweats are considered “excessive” if:

– They happen at least once a week
– They are not related to an underlying medical condition or environment
– They disrupt sleep

Some key features of night sweats include:

  • Occurring mostly during deep sleep phases like REM sleep
  • Leaving you sweaty when you wake up
  • Requiring you to change sleepwear and bedding

Night sweats can also be accompanied by flushing, clammy skin, headache, weakness, and fatigue upon waking.

What causes night sweats?

There are various reasons why someone might sweat excessively at night. Common causes include:


During menopause, declining estrogen levels can cause hot flashes and night sweats. These affect over 75% of menopausal women. Perimenopause refers to the transition period leading up to menopause, which also involves hormonal changes that provoke sweating.

Medical conditions

Many medical conditions have been associated with increased night sweat risk:

  • Infections – HIV, tuberculosis, endocarditis, osteomyelitis
  • Cancers – leukemia and lymphoma
  • Hormonal disorders – hyperthyroidism, hypoglycemia, carcinoid syndrome
  • Neurological conditions – autonomic neuropathy
  • Autoimmune disorders – rheumatoid arthritis, systemic lupus erythematosus

The sweating is thought to relate to fevers and cellular metabolism. Infections, cancers, and inflammatory diseases may trigger immune responses and release pyrogens that raise body temperature. Hormonal conditions also directly affect thermoregulation.

Medications and substances

Various prescription medications are associated with sweating as a side effect. These include antidepressants, pain medications, corticosteroids, tamoxifen, antihypertensives, and diabetes medications.

Recreational drugs (alcohol, opioids, cocaine) and withdrawal from substances may also induce sweating through effects on the sympathetic nervous system.

Obstructive sleep apnea

People with sleep apnea experience impaired breathing during sleep. This stimulates sympathetic nervous system activity, increasing perspiration. Night sweats are reported in over one-third of sleep apnea patients.


A condition called hyperhidrosis causes excessive, uncontrollable sweating. This may persist at nighttime. Primary hyperhidrosis has no apparent cause, while secondary hyperhidrosis relates to an underlying health issue.

Anxiety and stress

Anxiety activates the “fight-or-flight” response, part of which involves sweating to cool the body. Additionally, anxiety can stir up thoughts and emotions that raise body temperature. Stress is thought to trigger hormonal changes that expand blood vessels and increase sweating.

Environmental factors

Factors like high ambient temperature and humidity, heavy bedding, and warm sleepwear can all increase sweating during sleep.

Idiopathic causes

Sometimes the cause of night sweats remains unknown even after evaluation. These are termed “idiopathic night sweats”. Up to 22% of patients have no identifiable cause.

Who is affected by night sweats?

Night sweats can affect people across age groups and demographics. However, some characteristics make night sweats more likely:

Age – More common in mid-life and older ages.
Sex – Women are more prone, often relating to menopause.
Lifestyle factors – Overweight individuals and those living sedentary lifestyles sweat more at night.

Demographics like age and sex primarily relate to hormonal factors like menopause. Lifestyle factors that reduce heat tolerance may expand susceptibility.

When should you see a doctor?

Occasional mild night sweats are not necessarily concerning. However, speak to a doctor if any of the following apply:

– Sweating is excessive, frequent, or persistent
– Sweating disturbs sleep quality
– Other symptoms like fever, chills, or unexplained weight loss accompany sweating
– Sweating relates to an underlying condition like cancer or infection
– The cause of sweating is unknown

Evaluation by a physician can identify or rule out serious causes. Your doctor will review your medical history and perform relevant examinations and tests. These may include blood tests, imaging, biopsies, etc. Prompt assessment is key to directing appropriate treatment.

How are night sweats diagnosed?

Doctors take a systematic approach to diagnosing night sweats:

Medical history – Your doctor will ask about your sweating episodes, associated symptoms, medical conditions, and medication use. Details about sleep habits, lifestyle, and environment may provide helpful clues.

Physical exam – This checks for signs of infections, cancers, organ enlargement, etc. Your temperature, blood pressure, and reflexes may be assessed.

Blood tests – Blood counts, thyroid, liver and kidney function are evaluated. Inflammatory markers are checked to aid diagnosis.

Imaging tests – If cancers or anatomical issues are suspected, imaging like x-rays, CT, MRI, and PET scans may be undertaken.

Other tests – Biopsies, allergy testing, sleep studies, tilt-table testing, and hyperhidrosis assessments may be warranted for some patients.

Your doctor will select appropriate tests based on the findings and suspected causes. In many cases, a cause is identified based on history and basic tests alone.

Treatments for night sweats

Treatment depends on the underlying cause, when identifiable:

Menopause – Hormone therapy, certain antidepressants, and lifestyle changes may help manage menopausal night sweats.

Infections – Antibiotics, antivirals, or other antimicrobials are used according to the type of infection.

Medications – Switching or reducing doses of causative medicines can alleviate side effects.

Medical conditions – Treating the underlying illness can resolve associated night sweats.

Sleep apnea – Use of CPAP and oral devices relieves episodes of apnea and reduces night sweats.

Anxiety – Relaxation techniques, therapy, and medications help lower anxiety and stress levels.

Environment – Adjust room temperature, use lighter bedding, and wear moisture-wicking sleepwear.

For stubborn idiopathic cases, medications to reduce perspiration like low-dose anticholinergics may be trialed. Botox injections also inhibit sweat glands. Estrogen therapy helps some postmenopausal women.

Lifestyle and home remedies

Alongside medical treatment, lifestyle adjustments and home remedies can help manage night sweats:

– Maintain a cool, well-ventilated bedroom.
– Take a cool shower before bedtime.
– Use moisture-wicking sheets and sleepwear.
– Avoid heavy meals, alcohol, and spicy foods before bed.
– Exercise during the day to improve heat tolerance.
– Practice relaxing activities like yoga, meditation, or deep breathing before bed.
– Keep ice packs or a wet towel nearby to cool off if awoken by sweating.
– Use fans, open windows, and lower thermostat at night.
– Consume cool drinks like ice water if awakened by sweating.

When to seek medical care

Most instances of night sweats are not dangerous. However, promptly consult a doctor if you experience:

– Frequent or severe night sweat episodes
– Additional symptoms like unexplained weight loss
– Sweating that interferes with sleep
– Signs of infection like fever and chills
– Risk factors for cancer like smoking history
– Taking medications known to cause sweating

Sudden, severe, or persistent night sweats with other concerning symptoms should be evaluated quickly to identify underlying causes. Swift diagnosis allows specific treatments to be initiated in a timely manner.


Night sweats themselves are not medically dangerous. However, some associated complications can arise:

Dehydration – Profuse night sweats can lead to dehydration if fluids are not adequately replaced.

Sleep deprivation – Disrupted sleep reduces daytime energy and function. Cognitive impairment and accidents may result.

Skin irritation – Excessive moisture can cause itching and skin break down. Bacterial or fungal skin infections may develop.

Hypothermia – If sweating wakes you up and soaked clothing/bedding is not changed, shivering and body temperature drop can occur.

Impact of underlying condition – Severe infections, cancers, and undiagnosed diabetes/hyperthyroidism have their own significant complications if not treated promptly.

Practicing good sleep hygiene, maintaining hydration, and seeking appropriate medical care reduces the risks of complications.

When are night sweats a concern?

Night sweats are most concerning when:

– They are frequent, intense, or debilitating
– They are accompanied by unintentional weight loss, fever, or other symptoms
– They are new and unexplained, especially in older adults
– They relate to an underlying infection, illness, or malignancy
– They lead to sleep deprivation or skin damage

Benign causes like perimenopause and medications side effects are less worrisome. But new, severe, or persistent night sweats with other abnormalities should be evaluated promptly by a medical professional.

Can night sweats be prevented?

It is difficult to prevent night sweats altogether, especially when they relate to underlying medical conditions, menopause, or idiopathic causes. However, the following measures may help reduce night sweat episodes:

– Maintaining a cool sleeping environment

– Avoiding triggers like spicy food, alcohol, or heavy bedding

– Treating medical conditions, infections, and anxiety

– Adjusting problematic medications

– Using moisture-wicking bedding and sleepwear

– Maintaining good sleep hygiene with consistent bedtime routine

– Staying well hydrated, especially before bed

– Using fans, cooling mattress pads, or air conditioning

– Exercising during the day to improve temperature regulation

– Practicing relaxation techniques to lower stress

While not fail-safe, being proactive reduces the likelihood of excessive nighttime sweating and helps control episodes. Consult a doctor if sweating remains frequent or severe despite these prevention attempts.


Waking up sweaty and soaked in the middle of the night can be unpleasant and concerning. But night sweats are fairly common and generally not dangerous. They may relate to menopause, infections, medications, sleep disorders, anxiety, the environment, or have no clear cause.

Severe, frequent, or debilitating night sweat episodes should be evaluated by a doctor, especially when other symptoms are present. Testing helps diagnose any underlying condition requiring treatment. Home remedies and lifestyle measures can help reduce sweating. Prompt medical attention is advised if sweating is accompanied by fever, unintentional weight loss, or other abnormalities.

While inconvenient, night sweats are manageable in most people with an individualized treatment plan. Paying attention to patterns and triggers allows for better control. Maintaining good sleep hygiene and an optimal sleeping environment also helps minimize disruptive nighttime sweating.