The key for older people to sleep well at night could be how hot or cold their room is. Researchers say the best way to get a good night's sleep is to make sure the bedroom is between 20-25º Celsius. The researchers are from Harvard University and the Hinda and Arthur Marcus Institute for Aging Research in the USA. They asked 50 people aged 65 and older to wear a sleep monitor for a year and a half. The researchers found that the quality of sleep worsened when the room temperature was outside the 20-25-degree range. They also observed that 20ºC was the best temperature. The lead researcher said: "Sleep tends to come easier and is often deeper and more restful in a cooler environment."

The research is full of surprising information. It reported that temperature could affect sleep as much as experiencing pain or drinking alcohol before bedtime. The researchers found a 5-10 per cent drop in sleep quality when the temperature was lower than 20ºC or higher than 25ºC. They said poor sleep can lead to health issues. These include an inability to think clearly, mood swings, and higher levels of stress. Other problems include an increased chance of getting diabetes and cardiovascular diseases. The researchers said people should create, "a more comfortable home environment" to sleep well. They also highlighted, "the potential impact of climate change on sleep quality in older adults".