Temperature and Sleep: The Impact of a Cold Room

Dr. Kelvas emphasizes that extreme room temperatures, whether too hot or cold, make it difficult for the body to regulate hormones, leading to trouble falling or staying asleep.

Optimal Room Temperature for Better Sleep

The Sleep Foundation recommends keeping your room between 60°F (15.5°C) and 68°F (20°C) to aid the body’s natural thermoregulation, promoting quicker sleep onset and overall sleep quality.

How the Body Regulates Temperature

The body has a thermoregulatory mechanism that maintains internal temperature regardless of the environment. This involves physiological responses like sweating, shivering, and changes in blood flow.

• Sweating: When internal temperature rises, sweat glands produce moisture that evaporates, cooling the body.
• Shivering: When internal temperature drops, muscles contract rapidly to generate heat.
• Vasodilation and Constriction: Blood vessels near the skin dilate to release heat when the body needs cooling and constrict to conserve heat when needed.

These mechanisms prepare the body for sleep. For instance, when feeling cold in bed, putting on socks helps retain heat, while sticking your feet out from under the blanket can cool you down.

The Role of Temperature in Sleep

Throughout evolution, temperature has been a key signal for sleep and wake times, acting as a “zeitgeber” or time cue that influences circadian rhythms. Studies show people often fall asleep as temperatures drop and wake up as they reach their lowest.

Temperature affects sleep stages too. About two hours before sleep, core body temperature starts to drop, reaching its lowest during slow-wave sleep, while brain temperature also decreases slightly.

The Benefits of Sleeping in a Cold Room

Sleeping in a cold room offers several health benefits:

• Better Sleep Quality: A cooler environment helps release melatonin and prevents cortisol spikes, ensuring more time in restorative REM and slow-wave sleep phases.
• Fall Asleep Faster: Lowering core body temperature helps you fall asleep more quickly, supporting natural circadian rhythms.
• Better Weight Management: Cold temperatures activate brown fat, which burns white fat, aiding in weight management.
• Lower Risk of Diseases: Increased brown fat improves insulin sensitivity, reducing the risk of type 2 diabetes and other conditions. Cool rooms also support deep sleep, which may help prevent Alzheimer’s.

What to Do Without a Thermostat

If your home lacks heating and cooling, try these tricks to stay cool:

• Take a Warm Bath or Shower: While it may seem counterintuitive, a warm bath or shower can help cool the body by encouraging heat release afterward. Research shows that this can improve various sleep metrics, including sleep onset and overall quality.