How does your body temperature affect sleep?

Your body temperature is fundamentally connected to the overall quality of your sleep.

The human body has the capacity to maintain it’s body temperature by heat absorption, production and loss.

It has two zones to regulate.  One is the core made up of the abdominal, thoracic and cranial cavities which contain the vital organs.

The other is the shell zone which includes the skin and muscles, and is mostly affected by external temperature.

When the core temperature is too high the body releases it via the skin. Sweat is produced which evaporates to help lower the temperature.  When you are cold, the blood vessels constrict to conserve heat and the blood becomes more concentrated in the internal organs away from the limbs.

The body temperature of a healthy adult is between 36 and 37.8 degrees C and fluctuates during the body’s circadian rhythm.

When your temperature rises, you’ll more likely to feel awake and when it falls, you’ll probably start to feel tired.

There are two important factors involved in the release of melatonin (the sleep hormone).  One is the reduction in your body temperature and the other is the reduction of light.  You need darkness and a cool comfortable body in order to sleep well.

You may find that when you are dreaming, your body gets hot. 

This is because your brain’s natural temperature regulation system goes to sleep and your body temperature is governed by how warm or cool your bedroom is and how much bedding there is on your bed.   It’s better to have a hot water bottle on your feet than heating the whole bed.  The warmth on the feet and leaving the body cool helps move the internal thermostat to a cooler setting for the onset of sleep.  If you are a cold bird like me, put on a warm pair of bedsocks on rather than pilling on the bed covers.

A great way of cooling the body temperature before bed is to take a warm bath about an hour before bed.  It may seem odd to recommend a warm bath before bed when you are trying to reduce the body temperature.  The reason a warm bath is recommended is that as soon as you get out the bath, your skin temperature drops very quickly which helps with the onset of sleep.

Last note…alcohol. 

When your body is processing alcohol, it creates heat and dehydration.  If the body needs to lower the body temperature in order to sleep, but it’s still trying to metabolise the alcohol, you won’t get a good nights sleep.  Go easy on the alcohol if you’re not sleeping well!