Is too much or too little sleep a risk factor for death? Many patients asked me about this study after they heard it on the news. Well it looks like BOTH can be. At a conference of the American Heart Association this month Dr Cappuccio presented details of a provocative study just published in the Journal Sleep April 3, 2008. (http://www.journalsleep.org/ViewAbstract.aspx?citationid=3407). What this study showed was that a CHANGE in sleep duration during midlife was a risk factor for death; both for too much and too little sleep.
Here are the details: Over 10,000 British civil servants aged 35-55 were followed for about 20 years to answer the question of whether lack of sleep carries a price in terms of mortality.
FINDINGS: Death from cardiovascular disease was 2.4 fold higher in those who slept an average of 6-8 hours a night at baseline BUT cut their sleep to 5 hours a night over the next 5 years as compared to those who stayed with 6-8 hours. Short sleep duration is known to be associated with high blood pressure, weight gain and diabetes all of which increase risk of death from heart disease so there isn't much mystery here. The surprising finding, however, was that the study subjects who increased their sleep duration from 7-8 hours at baseline to 9 or more had a 2.1 fold increase in NONCARDIOVASCULAR mortality (death from causes other than heart disease). We don't really know why this is but it has been suggested that there may be possible links between too much sleep and depression and cancer-related fatigue.
What does this mean for you? If you are someone who has gone through a lifestyle change (had a child, changed to a more stressful job) and went from a pattern of 6-8 hours of sleep a night to 5 hours you need to be aware you might be putting yourself at risk. Try to get back to baseline. For those who sleep more than 9 hours a night tune in to why this might be the case for you. Is it mood related? You may want to touch base with your healthcare provider to report your increased requirement for sleep.