
In short: a hot flash opens the blood vessels in your skin and turns on sweating to dump heat fast. When it ends, you're wet, the sweat keeps evaporating, and damp sheets keep cooling you. So you swing from hot to shivering. Cleveland Clinic describes chills after hot flashes as common.
The cycle, step by step
- Your brain decides you're overheating.
- Blood rushes to your skin; you feel a wave of heat, often in the chest, neck and face.
- You sweat, sometimes heavily.
- The flash passes in a few minutes, but the sweat doesn't.
- Evaporation and damp fabric chill you. You pull the covers back on, and sometimes the next flash starts.
Why the swing wakes you up
Any big change in skin temperature tends to wake you. Going hot, then wet, then cold gives your body three chances to surface from sleep.
Breaking the cycle
- Fast-drying layers. Moisture-wicking sleepwear and sheets dry faster than cotton flannel.
- Swap, don't pile. Keep a dry top within reach instead of reaching for a heavier blanket.
- Keep the surface steady. A bed that holds a stable cool temperature takes the edge off the heat spike. Good Sleep's water-based topper can be set from 62°F up to 110°F, so you can find a setting that's cool without being cold. More at trygoodsleep.com.
- Towel layer. A thin towel over the pillow is easy to pull away when it's damp.
For the room side of the equation, see managing sleep temperature during menopause.
When to see a doctor
Chills with an actual fever, shaking chills, or sweats with weight loss or a cough aren't typical hot flashes. See a doctor promptly. Hot-cold swings that disrupt your sleep most nights are also worth raising.