Temperature and sleep

 

If you suffer from insomnia, you might want to turn your room temperature a bid lower. Even mildly warm environments can increase the number of times you wake up from sleep. It goes further, increased body temperature can also shift the quality of your sleep so you end up getting less REM sleep (dream stage) and less slow wave sleep (deep sleep).

 

At night, our body prepares for sleep. It does so by dropping its inner (core) temperature. You body temperature continues to drop as you sleep through the night and it reaches its lowest level about 3-4 hours after you fall asleep. If you are sleeping in a cool rather than warm environment, it is easier for your body to do what it needs to do to help you fall asleep but just as important, stay asleep.

 

In fact, if you simply lie down, you feel sleepy. This is because you are shifting heat from your core body to the periphery (hands and feet). As a result, heat escapes and your core body temperature drops just enough to make you a bid drowsy.

 

Ironically, daily bathing or a warm foot bath about 1-2 hours before bedtime has been shown to help folks fall asleep earlier. This is especially handy in the winter. This works because the warm bath initially increases your core body temperature. But then your blood vessels dilate to let the heat escape so you can reset your internal thermostat. This rapid drop in core temperature gives a special signal to your brain- the temperature is dropping, get ready for sleep. This is known as Thermoregulation.

 

The hands and feet follow a different beat though. While you want to keep your body temperature cool when you get in bed, you need to keep your feet and hands a bid warm and comfortable. This will let heat escape. You can wear socks or use a warm water bottle.

 

What is the ideal room temperature for sleep ? You might ask. It should be in the upper 60s and lower 70s Fahrenheit. Too cool of a room temperature is not comfortable either and does not necessarily add to your sleep quality. Remember, bedsides that ideal room temperature, comfortable pajamas, socks and blankets also influence your body temperature. So you have to put balance to all.

 

Chronic insomniacs have higher internal body temperature. Their thermostat is usually struggling to reset the body temperature lower at night. Insomnia symptoms have been linked to abnormalities in maintaining a regular body temperature rhythm.

 

Normal sleepers on the other hand seem to be blessed with a lower core body temperature at night. Lucky them.

 

References

 

  • Okamato Mizonu K, Mizono K, Michie S, Maeda A, Iizuka S. Effects of humid heat exposure on human sleep stages and body temperature. Sleep. 1999 Sep 15;22(6):767-73.
  • Sung EJ, Tochihara Y. Effects of bathing and hot footbath on sleep in winter. J Physiol Anthropol Appl Human Sci 2000 Jan;19(1):21
  • Raymann RJ, Swabb Df, Van Someren EJ. Skin temperature and sleep– onset latency: changes with age and insomnia. Physiol Behav. 2007 Feb 28;90(2-3):257-66. Epub 2006 Oct 27.
  • Morris M, Lack L, Dawson D. Sleep-onset insomniacs have delayed temperature rhythms.  Sleep. 1990 Feb;13(1):1-14.