At this time of year, I am often asked for advice on sleeping when it is so hot at night.
The temperature of the bedroom plays a significant role in determining how well you sleep. In general, the bedroom should be cool. At night, your body temperature naturally drops. Your body needs to lose heat and this is done mainly through the head and face, as these are the only areas that are not usually covered by bedding. A cool bedroom therefore facilitates this heat loss.
So how cool is cool? Many experts say that the ideal temperature for a bedroom is around 16-18oC. But whilst a cool bedroom is important, the temperature inside your bed makes a difference too. This temperature should be as close as possible to thermo-neutral, i.e. approximately 29oC. Usually you can heat your sleeping space to the correct level with your body heat alone, but if the bed is particularly cold a hot water bottle can help get the temperature up to the comfort level.
If either the room is too hot or you are too hot under the duvet, it is more difficult for the body to lose the heat that it needs to, resulting in disturbed sleep. This is why alcohol and big meals should be avoided close to bedtime: as they are both highly calorific, the body has to burn off these calories, generating extra heat. Being too cold is no better, as it prevents the body from achieving its optimal sleep temperature.
Good sleep is therefore all about juggling the different variables – air temperature, bedclothes and pyjamas – to ensure that your bedroom and bed remain as close as possible to the ideal temperatures. The general rule of thumb is warm bed / cool bedroom. Try to stick to it, and have a great summer!
Dr. Neil Stanley
Dr Neil Stanley is an independent sleep expert who has been involved in research for over 35 years. After starting out at the R.A.F. Institute of Aviation Medicine, he moved on to the University of Surrey's Human Psychopharmacology Research Unit, where he was Director of Sleep Research. Today, he travels the world lecturing on various aspects of sleep to both healthcare professionals and the public at large.