Medical Conditions That Cause Night Sweats

If you wake up drenched in sweat even in a cool room, a medical cause may be worth exploring. Night sweats — defined as sweating severe enough to soak your nightclothes or bedding — are distinct from simply sleeping warm.

Common Medical Causes

Hormonal Changes

Menopause is the most well-known cause of night sweats. Estrogen fluctuations affect the hypothalamus (your body’s thermostat), triggering false heat signals and sudden sweating. This can affect perimenopause as well.

Low testosterone in men can cause similar symptoms, though this is less commonly discussed.

Infections

Your immune system raises body temperature to fight infection. Some infections cause fever that spikes at night:

• Tuberculosis — historically called “consumption,” night sweats are a classic symptom
• Endocarditis — infection of the heart valves
• HIV — night sweats can be an early symptom
• Fungal infections — particularly in immunocompromised individuals

Medications

Several common medications list night sweats as a side effect:

• Antidepressants (SSRIs, SNRIs) — affect serotonin pathways that regulate temperature
• Hormone therapies — including tamoxifen used in breast cancer treatment
• Steroids — prednisone and similar drugs affect metabolism and sweating
• Fever reducers — aspirin and acetaminophen can cause rebound sweating

Hypoglycemia

Low blood sugar at night — particularly in people with diabetes on insulin — triggers an adrenaline response that causes sweating. If night sweats coincide with shakiness or hunger upon waking, blood sugar is worth checking.

Anxiety and Stress

Chronic anxiety activates the sympathetic nervous system, which controls sweating. This can cause night sweats even without elevated bedroom temperature.

When to See a Doctor

See a physician if your night sweats:

• Occur most nights for more than a few weeks
• Are accompanied by fever, unexplained weight loss, or fatigue
• Soak through clothing and sheets
• Are new and unexplained

A doctor can order targeted bloodwork (hormones, blood glucose, infection markers) to identify the cause.

What This Means for Hot Sleepers

If you have a medical cause, no mattress or cooling product will fully solve the problem. Treating the underlying condition is the priority. That said, products that wick moisture and promote airflow — cooling sheets, breathable mattresses — can meaningfully improve comfort while you address the root cause.