How to Sleep During a Heatwave
Quick Facts
Why Is It Harder to Sleep During Hot Weather?
Human sleep is closely linked to thermoregulation. As bedtime approaches, blood flow to the skin normally increases so the body can release heat and lower its core temperature. A hot bedroom, especially when combined with high humidity, makes that heat loss more difficult and may delay sleep, increase awakenings and reduce perceived sleep quality.
Humidity matters because sweating cools the body only when perspiration can evaporate. People with cardiovascular, respiratory or kidney disease may be particularly vulnerable during hot weather, while older adults, infants, pregnant people and those taking medicines that affect sweating, circulation or fluid balance may need additional precautions. Prescribed medicines should not be changed without advice from a clinician or pharmacist.
How Can You Keep a Bedroom Cooler During a Heatwave?
Close blinds, curtains or shutters on sun-facing windows before direct sunlight reaches the room. Keep windows closed when outdoor air is hotter than indoor air, and open them later if conditions outside become cooler and it is safe to do so. Turning off unnecessary lights, ovens, computers and other heat-producing appliances can also limit indoor heat accumulation.
Fans can improve comfort by increasing sweat evaporation, but they do not lower the room's temperature and may be less effective in extreme heat. Air conditioning or access to a cooled space provides more reliable protection when temperatures become dangerous. Use lightweight bedding, choose the coolest safe room available and follow local heat-health alerts, particularly when hot nights persist for several days.
Which Bedtime Habits Support Sleep in the Heat?
A cool or lukewarm shower can help remove excess heat without causing the discomfort of an ice-cold plunge. Lightweight, breathable clothing and bedding may support heat loss. Drink enough fluid during the day to avoid dehydration, but avoid consuming a large volume immediately before bed if it causes repeated nighttime bathroom visits. Alcohol can worsen dehydration and disrupt sleep architecture even when it initially causes drowsiness.
Keep usual sleep and wake times where possible, and reduce stimulating light and activity before bed. If heat symptoms include confusion, fainting, seizures, severe weakness, loss of consciousness or very hot skin, treat the situation as a medical emergency. Move the person to a cooler location, begin safe cooling and contact local emergency services promptly.
Frequently Asked Questions
A fan may improve comfort by moving air across the skin, provided it does not aggravate dry eyes, allergies or respiratory symptoms. It should not be relied upon as the only protection during extreme heat because it circulates air without reducing room temperature.
Not necessarily. A cool or lukewarm shower is often more comfortable and can support heat loss, whereas very cold water may trigger skin blood-vessel constriction and shivering.
Seek urgent medical help for confusion, collapse, seizures, loss of consciousness or other signs of heatstroke. Persistent dizziness, vomiting, severe headache or worsening symptoms also warrant prompt medical assessment.
References
- World Health Organization. Heat and health. Fact sheet.
- Centers for Disease Control and Prevention. About Sleep.
- ScienceDaily. Can't sleep in the heat? These 8 tricks could save your night. July 2026.