The research found that severe sleep difficulties were linked to almost eight fewer months of working life.Sleep difficulties and very long sleep linked to shorter working lives Image: Henrietta Hassinen / YleYle News10:37Healthy sleeping habits in middle age are linked to longer working lives, according to the findings of a study by the University of Turku.Researchers examined how sleep duration and sleep difficulties are associated with working-life expectancy — the number of years a person is expected to remain in employment.The study looked at working-life expectancy among Finns aged 50 and over, up to the age of 68.At age 50, the average expected working life was 13 years and two months.Moderate sleep difficulties were linked to around five fewer months of working life, rising to almost eight months among those with severe difficulties."Our findings highlight the importance of supporting sleep health and treating sleep difficulties in middle age, particularly among people in lower socioeconomic positions," says the study’s lead researcher, Saana Myllyntausta, docent of sleep and occupational psychology.The researchers also examined sleep duration.Among municipal employees who slept nine hours or more per night, working-life expectancy was around nine months shorter than among those who slept less than nine hours.In a second sample representing the Finnish population more broadly, the difference between the two groups was as much as two and a half years.International recommendations suggest that adults under 65 should generally get seven to nine hours of sleep per night.More than 70,000 Finns took part in the follow-up study.Study does not establish cause and effectThe researchers caution that the findings do not show that sleeping for long periods or experiencing sleep difficulties directly causes a shorter working life.For example, the study could not fully rule out the effects of illnesses and mental health on the relationship between sleep and working-life expectancy.Previous research has nevertheless linked good sleep health with factors including better performance at work, cognitive functioning and overall health.