The body drops its core temperature by 1-2 °C as it falls asleep. A cool room supports the drop; a warm room fights it. This is one of the few levers that the body cannot override with willpower.
The 18-20 °C window
Sleep researchers consistently find the optimal bedroom range to be 18-20 °C (65-68 °F). Cooler than 16 °C and the body begins to defend core temperature; warmer than 22 °C and the drop slows noticeably.
A foot out of the duvet
Heat radiates from the extremities. Letting one foot sit outside the duvet gives the body a low-effort way to dump heat without disturbing the rest of the body.
Shower, then cool-down
A warm shower 90 minutes before bed raises skin temperature briefly. As it falls, the drop mimics the natural sleep-onset cooling and can make the transition faster.
You do not need to feel cold to sleep well. You need to feel cool.
