Course Content
Sleep Well Coach Training
About Lesson

Our bodies naturally have a dip in core temperature (about 1°C) over the course of 24 hours. Have you ever noticed suddenly feeling chillier in the evening and reaching for a blanket or putting on the fire despite the heating being on? This is due to the core temperature of the body starting to drop about 2 hours before we go to bed, coinciding with the release of melatonin, so we start to feel tired and ready for sleep. It drops to its lowest point around 2-4am and then we start to warm up again signalling to the body it is time to wake up. 

We lose our body heat through our extremities, via a process known as vasodilation, which is why our feet and hands can feel warm at night. 

On a personal note, as a last resort when I have woken in the middle of the night and cannot get back to sleep I put my feet under cold water which on returning to bed instantly lulls me to sleep. I am assuming this is due to the blood being diverted to my feet to warm them up and consequently cooling me back down. Although this seems slightly at odds with the suggestion below that you heat yourself up to drop body temperature.

If we have a higher core temperature during sleep this has been shown to be linked to a lower amount of deep sleep (1), which can have a noticeable effect on how we feel when we feel when we wake up ie: the feeling of being groggy even though you think you have slept well.

If the Bedroom is Too Hot

We can feel very restless and find it difficult to sleep and the warm room can interfere with your body temperature regulation (mentioned above). This can make it difficult to fall asleep, even though we are tired, making us more fatigued and exhausted. 

The bedroom, therefore, needs to be cool to induce sleep, ideally between the temperature of 15°C -18°C. This can vary depending on the person so do check in with your client to work out a good temperature for their room.

Bedding will also have an impact on body temperature. We need to feel warm and cosy under our bedding. This also creates a temperature gradient where it is cooler outside the covers and warmer under them, which allows for efficient loss of heat from your head and also hands and feet if out from under the cover. 

Achieving a Suitable Sleeping Temperature

  • If you live in a hot place (or we get a hot summer here in the UK) close the curtains/blinds during the day which can help to reduce heat build-up in the bedroom.
  • Turning down (or switching off) the thermostat at night time.
  • Use a fan if it is a particularly warm night.
  • Take a warm bath (or shower) about an hour before bed (2), which starts the process of heat loss from your body indicating it is time to sleep and can help to fall asleep quicker and induce deeper sleep. 
  • Exercise up to 2 hours before bed can reduce how long it takes to sleep (3), attributed to the effect of exercise heating up the body and then naturally cooling down. It also helps you to feel more tired. This can be particularly useful if you have a job/day which doesn’t involve much physical activity. Exercise can also help to destress and reduce anxiety. 
  • Ensure your bedding is helping you get your temperature balance right (more on bedding in the lesson on ‘The Bed’)
  • Not eating close to bedtime as digestion increases our body temperature slightly.
  • If someone is feeling too hot in bed suggest sticking out their hands or feet to help with this temperature gradient of heat loss and see if it induces deeper sleep.
References
  1. Okamoto-Mizuno K, Mizuno K. Effects of thermal enviroment on sleep and circadian rhythm. J Phsyiol Anthropol 2012, 31:14
  2. Harding EC, Franks NP, Wisden W. The temperature dependence of sleep. Front Neurosci 2019: 13
  3. Frimpong E, Mograss M, Zvionow T, Dang-Vu TT. The effects of evening high-intensity exercise on sleep in healthy adults. A systematic review and meta-analysis. Sleep Med Rev 2021; 60: 101535