University College London (UCL) researchers have found sleep duration has significant impacts to health, especially in older adults – getting less than five hours of sleep each night could increase the risk of being diagnosed with multimorbidity i.e., two or more diseases including cardiovascular disease and cancer.
The research involved more than 7,000 participants over 50 years old, who had been monitored for at least 25 years.
People who reported getting five hours of sleep or less at age 50 were 20% more likely to have been diagnosed with a chronic disease and 40% more likely to be diagnosed with two or more chronic diseases over 25 years, compared to people who slept for up to seven hours.
Additionally, sleeping for five hours or less at the age of 50, 60, and 70 was linked to a 30% to 40% increased risk of multimorbidity when compared with those who slept for up to seven hours.
Researchers also found that sleep duration of five hours or less at age 50 was associated with 25% increased risk of mortality over the 25 years of follow-up — which can mainly be explained by the fact that short sleep duration increases the risk of chronic disease(s) that in turn increase the risk of death.
“Multimorbidity 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,” said Dr. Severine Sabia from UCL’s Institute of Epidemiology & Health.
“As people get older, their sleep habits and sleep structure change. However, it is recommended to sleep for 7 to 8 hours a night – as sleep durations above or below this have previously been associated with individual chronic diseases [and now] also associated with multimorbidity.
“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.”
As part of the study, researchers also assessed whether sleeping for a long duration, of nine hours or more, affected health outcomes. There was no clear association between long sleep durations at age 50 and multimorbidity in healthy people.
However, if a participant had already been diagnosed with a chronic condition, then long sleep duration was associated with around a 35% increased risk of developing another illness. Researchers believe this could be due to underlying health conditions impacting sleep.