Is Too Much Sleep Bad For You? More Than 8 Hours Of Sleep May Increase Your Risk Of Stroke

In the worst iteration of the Goldilocks dilemma in recent memory, a new study from the University of Cambridge suggests that there is such a thing as too much sleep, and it may lead to some nasty consequences. According to the latest research, adults who get more than eight hours of sleep have an increased risk of stroke, and a significant one at that. In fact, when compared to those who got only six to eight hours of sleep a night, adults who spent more than eight hours in a state of peaceful repose were 46 percent more likely to suffer a stroke. You just can't win anymore.

These findings stand in stark opposition to recommendations from the National Sleep Foundation, which dictate that adults between 18 and 64 years of age should be sleeping an average of seven to nine hours a night. But the University of Cambridge study, which followed nearly 10,000 middle-age adults for almost a decade, negates this commonly held opinion. In their research, scientists found that 346 of their subjects had a stroke during the observation period. And after taking age and gender into consideration, the other significant factor seemingly at play was the amount of sleep these individuals got on a daily basis. The results were clear — those who slept more than eight hours were at an increased risk for stroke, though those who slept for less than six hours also were more likely to have a stroke.

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The good news, of course, is that it seems that a rather small proportion of the population, or at least the sample population, gets an unhealthily large amount of sleep. Whereas 7 out of 10 participants said they slept between six and eight hours a day, just 10 percent claimed to sleep more than eight hours, because really, who has time for that?

Historically, it has always been lack of sleep that has been branded as the culprit in many health risks and disorders, but this is one of the few studies that have suggested the dangers of too much sleep. Whereas sleeping too little, which is to say, fewer than six hours a night, has been shown to raise cortisol levels, leading to higher blood pressure and potential for stroke, it is unclear why sleeping more would disrupt normal body function. It seems more likely, then, that sleeping for more than the recommended amount is not so much a cause of a problem, but rather an indication of issues to come.

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Dr. Alberto Ramos of the University of Miami’s Miller School of Medicine and James Gangwisch of Columbia University noted in the study, "Long sleep duration could therefore be a harbinger of stoke through its association with potent cardiovascular risk factors. Lengthening sleep duration could portend strokes and serve as an early warning sign, suggesting the need for further diagnostic testing or for taking precautionary measures."

Dr. Madina Kara, a research manager at the Stroke Association, pointed out that nothing in the study suggested that sleeping too much actually caused stroke, telling The Independent, "The known risk factors [for stroke] include high blood pressure, smoking and lack of exercise. Eating healthily, getting active and quitting smoking can make a big difference in reducing your risk of stroke."

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Still, the study reveals some interesting correlations. For one, researchers noticed that sleeping too much presented a much greater issue for older individuals — those over the age of 63 were much more likely to be adversely affected by too many ZZZ's. On the other hand, sleeping too little seems more dangerous for younger people, a cruel twist of fate considering what would appear to be natural lifestyle changes that occur with age. They also noticed that varying lengths of sleep were linked with different kinds of stroke — those who slept too little most often suffered ischemic strokes, which are caused by clots that block blood flow to the brain, whereas those who sleep too much seem more likely to experience hemorrhagic strokes, which occur when blood vessels rupture and bleed into the brain.

Ultimately, when taken in conjunction with previous studies, researchers determined that sleeping too little was actually less cause for concern than sleeping too much — the former was associated with an increased risk of 15 percent, whilst the latter came with a 45 percent greater risk.

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Further research is needed to fully understand the effects of sleep on health, particularly cardiovascular health, but the established link is certainly a curious one. Yue Leng, a PhD candidate at the University of Cambridge, told Science Daily, "It's apparent both from our own participants and the wealth of international data that there's a link between sleeping longer than average and a greater risk of stroke. What is far less clear, however, is the direction of this link, whether longer sleep is a symptom, an early marker or a cause of cardiovascular problems."

So in the meantime, stick with the recommended eight hours of sleep — no more, no less. Because apparently, anything other than perfection could be deadly.

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