Hot flashes before your period: why they happen and what helps

What premenstrual hot flashes feel like

A hot flash is a sudden feeling of heat, usually in the face, neck and chest, sometimes with flushing, sweating and a racing heart, followed by feeling chilly. Before a period, they tend to be milder and shorter than menopausal flashes, and often show up as night sweats: waking up hot and damp in the last few nights of your cycle.

• Sudden warmth spreading over your face, neck or chest
• Flushed skin and sweating, then a chill
• Waking hot or sweaty, kicking the covers off
• Feeling generally warmer than usual in the week before your period
• Settling a few days after bleeding starts

Why you get hot before your period

Progesterone turns up the heat

After ovulation, progesterone acts on the brain's thermostat. Core body temperature runs about 0.3 to 0.7°C higher in the luteal phase than before ovulation, and the difference is clearest during sleep. That's the same rise that basal temperature tracking and wrist temperature sensors pick up. On its own it just makes you feel warmer, but it narrows the margin before you tip into sweating.

The estrogen drop

Estrogen helps keep the brain's temperature-control center stable. When it falls sharply in the last days of the cycle, the thermostat can become more sensitive and misfire, triggering a flush to shed heat even when you don't need to. It's the same mechanism behind menopausal hot flashes, just brief and smaller.

The perimenopause link

In perimenopause, usually from your 40s, estrogen swings become bigger and less predictable. Hot flashes and night sweats often appear first around periods, before they happen at random times. If you're in your 40s and premenstrual hot flashes are new, that's a common early sign. Our perimenopause self-check can help you see the bigger picture.

What helps

1. Keep your bedroom cool, around 16 to 19°C (60 to 67°F), with a fan and breathable bedding.
2. Layer up so you can strip off quickly. Cotton or moisture-wicking fabrics help.
3. Keep cold water by the bed and a spare top if night sweats wake you.
4. Notice your triggers: alcohol, hot drinks, spicy food, caffeine, stress and hot rooms commonly set off flushes.
5. Move regularly. Fitness helps your body regulate temperature, though avoid hard workouts right before bed.
6. Try slow, paced breathing when a flush starts. Some people find it shortens them.
7. If you're in perimenopause, talk to a doctor about treatment. Hormone therapy is the most effective treatment for hot flashes, and there are non-hormonal options too.

Heat, sleep and mood

Night sweats break up sleep, and short sleep amplifies the irritability and low mood many people feel before their period. Daytime flushes can also feel embarrassing, which adds to premenstrual anxiety. Cooling your sleep space in the luteal week is one of the simplest ways to protect your mood. See insomnia before your period.