Night Sweats: Causes, Myths & When to See a Doctor

Introduction

You wake up in the middle of the night, sheets soaked, heart racing — even though the room isn't particularly warm. Night sweats are surprisingly common, but they're also one of the most misunderstood symptoms in both medicine and everyday life. Here's what's actually causing them — and when you should be concerned.

What Exactly Are Night Sweats?

Night sweats are episodes of excessive sweating during sleep, severe enough to soak your nightclothes or bedding. They're distinct from simply being too warm — genuine night sweats occur even when the sleep environment is cool, and they can drench bedding despite mild temperatures.

Common Causes of Night Sweats

Hormonal Changes — Menopause and Perimenopause

The most common cause in women over 40. Fluctuating and declining estrogen levels disrupt the hypothalamus (the brain's thermostat), causing sudden waves of heat followed by profuse sweating. Up to 75% of menopausal women experience hot flushes and night sweats.

Anxiety and Stress

Persistent anxiety keeps the sympathetic nervous system activated — even during sleep. This can produce night sweating unrelated to any physical cause. It's one of the most under-recognised connections between mental health and physical symptoms.

Medications

Antidepressants (particularly SSRIs and SNRIs), fever-reducing medications taken at bedtime, and hormone therapies are all common medication-related causes of night sweats.

Infections

Night sweats are a classic symptom of several infections, including tuberculosis, HIV, and endocarditis. If night sweats are accompanied by fever, unexplained weight loss, or fatigue, infection should be ruled out.

Low Blood Sugar

Nocturnal hypoglycaemia — a drop in blood sugar during sleep — causes the body to release adrenaline, which triggers sweating. It's particularly common in people with diabetes who use insulin.

Sleep Apnoea

People with untreated sleep apnoea frequently experience night sweats. The repeated breathing disruptions cause partial awakenings that activate the sympathetic nervous system and trigger sweating.

What Night Sweats Are NOT

Myth: Night sweats always mean something serious. Reality: Most night sweats have benign causes — warm bedding, alcohol before bed, mild anxiety, or a warm room. They become medically significant when they're frequent, drenching, and accompanied by other symptoms.

Myth: Only older women get night sweats. Reality: Night sweats affect all ages and genders. They're common in teenagers (hormonal changes), men (testosterone fluctuations, anxiety), and children (infections, anxiety).

When Should You See a Doctor?

Seek medical attention if: night sweats occur several times a week, they're accompanied by unexplained weight loss, you also have daytime fever, or they've appeared suddenly with no obvious cause. These warrant blood tests and a thorough evaluation.

Self-Help Measures

Keep the bedroom cool (16-19°C / 61-66°F is optimal)

Use breathable bedding — linen or moisture-wicking fabric

Avoid alcohol and spicy food in the evening

Address underlying anxiety through relaxation practices

Speak to your doctor about reviewing any medications