What causes hot flashes?

Bottom lineHot flashes are sudden waves of heat with flushing and sweating, the most common perimenopause and menopause symptom, caused by changing estrogen making the brain's temperature thermostat (the hypothalamus) overreact and dump heat; triggers include stress, caffeine, alcohol, spicy food, heat, and smoking. Avoiding triggers, staying cool, and managing stress help, and HRT is the most effective treatment for moderate to severe hot flashes, with non-hormonal options available.

Hot flashes are sudden waves of heat, often with sweating and flushing, that are the most common symptom of perimenopause and menopause. They're driven by changing estrogen levels affecting the body's temperature control.

Why they happen

Falling and fluctuating estrogen affects the hypothalamus, the brain's thermostat, making it more sensitive to small temperature changes. It overreacts, triggering the body to dump heat: blood vessels widen, you flush, and you sweat.

What they feel like

• A sudden wave of heat in the face, neck, and chest
• Flushing, sweating, sometimes a rapid heartbeat
• Often followed by a chill
• Last from seconds to several minutes
• At night, they cause night sweats and disrupted sleep

Common triggers

• Stress and anxiety
• Caffeine, alcohol, and spicy food
• Heat and warm rooms
• Smoking

What helps

• Identify and avoid triggers; dress in layers
• Keep cool (fans, cool drinks)
• Manage stress; regular exercise
• HRT is the most effective treatment for moderate to severe hot flashes
• Non-hormonal medications for those who can't take HRT

When to see a doctor

• Hot flashes disrupting sleep or daily life
• To discuss HRT and other treatments

Read our perimenopause and menopause guide and what is HRT.

Femora helps you track hot flashes and triggers as part of stage-aware symptom logging.