When feeling ill, doctors often recommend plenty of fluids and plenty of rest, so it makes sense that plenty of sleep can lead to a long life. However, a new study has found that getting more than nine hours of sleep a night can actually lead to an earlier grave.
Senior research fellow Dr. Melody Ding, Professor Adrian Bauman, and other researchers at the University of Sydney, published their study results last week in the journal PLOS Medicine. The research analyzed data from the 45 and Up Study, which is following more than 230,000 Australian participants and studying their health as they age. At the beginning of the study, the participants filled out a survey that gave baseline data on their lifestyle. They then recorded behavior such as smoking, drinking, diet, and physical activity.
The researchers looked at lifestyle behaviors like smoking, high alcohol consumption, poor diet, and physical inactivity, which are known to increase the risk of disease and death. They also looked at too much sitting and too much sleeping to see if they would also have an effect on lifespan. They compared these factors in different combinations to see which combination was most associated with an increased risk of premature death, from any cause.
The statistics showed that when someone sat for more than seven hours a day, exercised less than 150 minutes each week, and slept more than nine hours a day, they were four times more likely to die early than someone with healthier habits. The researchers found the same four-fold increase in mortality among those who smoked, drank, and had less than seven hours of sleep each night.
These were not the only unhealthy habits to increase the chance of mortality in the study. The researchers also found that the risk of early death was doubled when the participants were physically inactive and got too much sleep, when they were physically inactive and sat too much, and when they were smokers who also drank a high amount of alcohol.
The researchers suggest that information about which combinations of unhealthy habits have the biggest effect on mortality could help direct public health policy. That way, efforts can be directed toward promoting a healthier lifestyle in the most at-risk groups.
Diseases such as heart disease, diabetes, and cancer kill more than 38 million people worldwide, more than infectious diseases, and they seem to be a growing problem. Research has linked many of these deaths to unhealthy lifestyles, and lifestyle intervention is often the first way doctors try to prevent and treat these diseases. Quitting smoking, cutting back on alcohol, eating healthy and losing weight, becoming more active, sitting less, and getting between seven and nine hours of sleep each night could help improve overall health, potentially leading to a longer life.
Previous studies have linked lack of sleep with an increased risk of obesity, heart disease, and diabetes. Lack of sleep has also been associated with a lower pain threshold, poor sex life, poor mood, poor thinking and memory, an increased risk of infectious disease, and an increased risk of injury. However, it seems that too much sleep can also have negative effects on health.
The current research did not examine reasons why more than nine hours of sleep each night seemed to have a negative effect on health. However, previous research has linked too much sleep with low socioeconomic status and depression. It is possible that these underlying causes of oversleeping are having a poor effect on health on their own, and it may not actually be the act of sleeping too much that negatively affects health.
The amount of sleep needed changes throughout a lifetime, but the average adult should be getting around eight hours a night. Treating underlying causes of poor sleep, such as sleep apnea, can help people get the right amount.