From the Guidelines
The ideal sleeping temperature for most adults is between 18-24 °C, as recommended by the World Health Organization (WHO) 1. This temperature range is considered optimal for promoting better sleep quality, comfort, and overall well-being. The thermal environment plays a crucial role in sleep quality, and temperatures that are too cool or too warm can cause discomfort and decrease work performance and well-being 1. Individual preferences may vary slightly, with some people preferring temperatures at the lower or higher end of this range. Factors like bedding thickness, pajama type, and whether you sleep alone or with a partner can affect your optimal temperature. If you tend to sleep hot, aim for the cooler end of the range; if you often feel cold at night, the warmer end might be better. Maintaining consistent temperature throughout the night is also important, as fluctuations can disrupt sleep cycles. Some key points to consider when determining your ideal sleeping temperature include:
- The optimal relative humidity (RH) in indoor air for health and work performance is between 40 and 60% 1
- National guidelines for indoor temperature and RH vary, but the most commonly recommended range is 40-70% for RH and 18-24 °C for temperature 1
- A temperature range of 18-24 °C can help facilitate the natural drop in core body temperature that occurs during sleep, promoting faster sleep onset and better sleep quality 1.
From the Research
Optimal Sleep Temperature
The ideal sleep temperature is a crucial factor in determining the quality of sleep. According to the study 2, thermoneutrality is reached for an environmental temperature of 30-32 degrees C without night clothing or of 16-19 degrees with a pyjama and at least one sheet.
Factors Affecting Sleep Temperature
Several factors can affect the optimal sleep temperature, including:
- Age: Certain factors, including age, can favour internal desynchronization 2.
- Noise: Noise also modifies sleep structure and above 50dB shortens total sleeping time 2.
- Body temperature: Sleep is most conducive in the temperature minimum phase, but is inhibited in a "wake maintenance zone" before the minimum phase, and is disrupted in a zone following that phase 3.
- Sleep disorders: Different types of insomnia symptoms have been associated with abnormalities of the body temperature rhythm 3.
Recommendations for Sleep Temperature
While there is no specific temperature recommended for sleep, the studies suggest that:
- A cooler temperature may be beneficial for sleep, as it can help to increase the duration of deep sleep 4.
- A warm shower or bath before bedtime can help to improve sleep quality by increasing blood perfusion to the palms and soles and enhancing body heat dissipation 4.
- The optimal timing and duration of passive body heating before bedtime are still unknown and require further investigation 4.
Sleep Quality and Duration
Sleep quality and duration are crucial for overall health, and the optimal sleep temperature can play a role in determining sleep quality. The study 5 found that sleeping 7-8.5 hours per night is associated with longer healthy and chronic disease-free life expectancy.