Heat and sleep: a complicated duo

Glowing feet, damp hair, sheets too warm, sheets kicked off, sheets back on. The classic tropical-night routine. Why exactly does heat make sleep so hard? And why do some people seem to manage it while others lie awake until 3am? It comes down to specific biology — and once you understand what's going on, the right fixes become obvious.

1. Why your body fights heat at night
2. The body temperature curve
3. What makes it worse
4. What actually helps
5. Setting up your bedroom for heat

Why your body fights heat at night

Falling asleep depends on your body lowering its core temperature by about 1°C. This isn't optional — it's a hardwired part of the sleep process. Your brain reads the temperature drop as a signal that it's safe to switch off. In a hot bedroom, your body can't lose heat efficiently, so the temperature drop is delayed or doesn't happen properly. You feel tired but can't sleep. Or you fall asleep, but only lightly, and wake easily.

The body temperature curve

Your core temperature naturally drops in the late evening and bottoms out around 4–5am. Heat disrupts this curve in two ways. First, the initial drop is shallower in a warm room. Second, the deepest sleep stages — slow-wave sleep — are more fragile when body temperature is elevated. So even when you're asleep in heat, the sleep is less restorative.

What makes it worse

• Heavy duvets — designed to retain heat, which is exactly wrong now
• Polyester or synthetic bedding — traps heat and moisture against the skin
• Alcohol in the evening — disrupts the body's thermoregulation, makes night sweats worse
• Late heavy meals — increase metabolic heat through the night
• Stress — raises core temperature; high stress + hot night is a difficult combination

What actually helps

• Lukewarm shower 60–90 min before bed — triggers a temperature drop
• Cool feet — your feet are major heat-radiators. Keep them outside the duvet, or run cold water over them before bed
• Breathable bedding — see our cooling bamboo range
• Lighter duvet — switch to a summer-weight duvet
• Bedroom temperature 16–19°C — see our temperature guide
• Hydration during the day — dehydration makes thermoregulation harder

Setting up your bedroom for heat

The bedroom should be the coolest room in the house during a heat wave. Concrete steps:

1. Close blinds and curtains during sun hours
2. Block off the bedroom from heat-generating rooms (kitchen, sun-facing living room) by closing internal doors during the day
3. Open windows after 10pm and create cross-flow if possible
4. Switch to summer bedding for the season — bamboo specifically performs well in heat
5. Have a glass of water and a small towel by the bed

Heat and sleep don't have to be a battle. With the right setup, you can sleep through 28°C nights as well as you do at 18°C.