Regularly getting less than six hours of sleep a night could increase risk of cancer and early death for people suffering from certain health conditions.
This is according to a new study published in the Journal of the American Heart Association.
Getting sufficient sleep could be “protective” for middle-aged adults who have high blood pressure, type 2 diabetes, heart disease or stroke, the report found.
Scientists analysed data from 1,654 people aged 20 to 74 from the Penn State Adult Cohort database.
People were categorised into two groups: one group who suffered from stage 2 high blood pressure or type 2 diabetes, and one which suffered from heart disease or stroke.
Researchers asked participants to spend one night at a sleep laboratory between 1991 and 1998. They then tracked their cause of death up to the end of 2016.
Out of 512 people who died during this period, a third had heart disease or stroke as their cause of death, and a quarter died due to cancer.
Individuals in the high blood pressure or diabetes group who slept less than six hours during the night at the sleep laboratory had double the increased risk of dying from the related conditions of heart disease or stroke.
Those in the group of who had already suffered from heart disease or stroke, who slept less than six hours, had three times the increased risk of dying from cancer.
Lead study author Julio Fernandez-Mendoza, associate professor at Pennsylvania State College of Medicine, said: “Our study suggests that achieving normal sleep may be protective for some people with these health conditions and risks.
“However, further research is needed to examine whether improving and increasing sleep through medical or behavioural therapies can reduce risk of early death.”
He added: “Short sleep duration should be included as a useful risk factor to predict the long-term outcomes of people with these health conditions and as a target of primary and specialised clinical practices.
“I’d like to see policy changes so that sleep consultations and sleep studies become a more integral part of our healthcare systems.
“Better identification of people with specific sleep issues would potentially lead to improved prevention, more complete treatment approaches, better long-term outcomes and less healthcare usage.”
The study results suggest people with high blood pressure or diabetes could cancel out their increased early death risk if they slept more than six hours a night.
Yet researchers also warned of the possible influence the first-night effect – where study participants sleep worse the first night in a lab compared to following nights – might have had upon these results.