Scientists identify sleep tipping point for poor health

Adults over 50 who get less than five hours of sleep at night may have an increased risk of developing at least two chronic diseases, research suggests.

Evidence from self-reported data indicates that compared to those who slept for up to seven hours a night, people who reported getting five hours or less shut eye were 30% more likely to be diagnosed with diseases – such as cancer, diabetes or heart disease – over the span of 25 years.

Based on the findings, published in the journal Plos Medicine, the researchers involved in the study recommend getting between seven and eight hours of sleep every night.

Dr Severine Sabia, of the University College London’s Institute of Epidemiology & Health, and Inserm, Universite Paris Cite, who is also a lead author on the study, said: “Multimorbidity (two or more chronic diseases) is on the rise in high income countries and more than half of older adults now have at least two chronic diseases.

“This is proving to be a major challenge for public health as multimorbidity is associated with high healthcare service use, hospitalisations and disability.

“As people get older, their sleep habits and sleep structure change.

“However, it is recommended to sleep for seven to eight hours a night – as sleep durations above or below this have previously been associated with individual chronic diseases.

“Our findings show that short sleep duration is also associated with multimorbidity.”

As part of the study, the researchers looked at self-reported sleep duration data from nearly 8,000 adults, measured at age 50, 60 and 70.

The team found at age 50, those who slept five hours or less had a 30% greater risk of multimorbidity over the 25 years of follow-up, compared with those who slept seven hours.

At 60, those who slept five hours or less had a 32% greater risk, and at 70, had a 40% greater risk, compared with seven hours per night.

Researchers also found that sleep duration of five hours or less at age 50 was associated with 25% increased risk of mortality.

This is possibly because short sleep duration increases the risk of chronic diseases that, in turn, increases the risk of death, the scientists said.

Dr Sabia said: “To ensure a better night’s sleep, it is important to promote good sleep hygiene, such as making sure the bedroom is quiet, dark and a comfortable temperature before sleeping.

“It’s also advised to remove electronic devices and avoid large meals before bedtime.

“Physical activity and exposure to light during the day might also promote good sleep.”

The research was funded by the National Institute on Aging, part of NIH, UK Medical Research Council, the British Heart Foundation, and Wellcome.