The importance of sleep for one’s general health is not news. Getting a good night’s sleep is usually an important factor of how the day is going to go, not to mention that long periods of poor-quality sleep can affect both mental and physical health.
A research published this summer in Digital Medicine has linked sleep quality with life expectancy, showing that a large number of sleep interruptions in particular can significantly shorten a person’s life.
The study, led by Stanford University, had 12,000 participants whose sleep was recorded, from heartbeat and breathing, to movement of the chin and legs. The data was then analysed by sleep specialist Emmanuel Mignot, MD, Ph.D., and his colleagues, using a machine learning algorithm to determine someone’s “sleep age”.
As people get older, the quality of their sleep lowers and the researchers wanted to see if certain sleep parameters associated with older age could predict a shorter lifespan. The changes in these sleep parameters, which indicate the “sleep age”, are potential warnings of health problems.
Our main finding was that sleep fragmentation, when people wake up multiple times throughout the night for less than a minute without remembering it, was the strongest predictor of mortality.Emmanuel Mignot, lead researcher
Once the data was analysed, the sleep age given by the algorithm showed an average difference of 14.9 from the actual age. After controlling for demographics, sleep and health covariates, each 10-year increment in age estimate error (AEE) was associated with an increased all-cause mortality rate of 29%. An increase from −10 to +10 years in AEE translates to an estimated decreased life expectancy of 8.7 years, the study showed.
The research revealed that “greater AEE was mostly reflected in increased sleep fragmentation, suggesting this is an important biomarker of future health independent of sleep apnoea”. “This is different from a person realizing they were waking up, which happens during sleep disorders such as insomnia”, Dr Mignot clarified.
As the golden rule of research states “correlation does not mean causation”, so academics are yet to determine exactly how sleep quality affects life expectancy. In this regard, Dr Mignot revealed he and his team are now working with scientists from Harvard University to conduct a larger study, of 250,000 participants. At the same time, they will also look into how sleep quality can increase the risk for heart attack and Alzheimer’s.