Getting less than five hours of sleep in mid-to-late life could be linked to an increased risk of developing at least two chronic diseases. 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.
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 30-40% increased risk of multimorbidity when compared with those who slept for up to seven hours (PLOS Medicine), says a University College London release.
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. Researchers used self-reported data on sleep, which is likely to be subject to reporting bias, although using data on 4,000 participants whose sleep was measured via an electronic device confirm the findings.
