Excess Sleep Can Increase Stroke Risk by 85% by Dr. Joseph Mercola for Mercola
While the pitfalls of too little sleep have been well documented, there are also risks of sleeping too much, which is generally defined as more than nine hours a night. Specifically, excessive sleep, along with long midday naps, may increase your risk of stroke, according to a Chinese study involving 31,750 people.1
It’s unclear exactly why excess sleep increases stroke risk, but long nappers and sleepers are more likely to have increased waist circumferences and inactive lifestyles, both of which are risk factors for stroke. However, other mechanisms could also be at play, as the relationship between sleep and cardiovascular health is complex and still being explored.
Too Much Sleep, Long Naps Increase Stroke Risk by 85%
Compared with sleeping seven to eight hours a night, those who slept for nine hours or more had a 23% greater risk of stroke, while shorter sleep (less than six hours a night) had no significant effect on stroke risk. Those who took long midday naps of more than 90 minutes also had a greater stroke risk — by 25% — than those who napped for 30 minutes or less.2
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The greatest risk of all, however, occurred among those who both slept for nine hours or more at night and napped for more than 90 minutes. This excessive sleep combination increased stroke risk by 85% compared to moderate sleepers and nappers.
Sleep quality also matters, and the researchers found, “Compared with good sleep quality, those with poor sleep quality showed a 29%, 28% and 56% higher risk of total, ischemic, and hemorrhagic stroke, respectively.”3 People who were long nighttime sleepers with poor sleep quality were 82% more likely to have a stroke compared to moderate sleepers with good-quality sleep.
What’s more, even switching sleep duration from moderate to long increased stroke risk. Those who switched from seven to nine hours of sleep a night to nine hours or more were 44% more likely to have a stroke than persistent moderate sleepers.4 Previous research has also linked sleeping for more than eight hours per night with stroke, particularly in the elderly and women.5
The Link Between Sleep Duration and Stroke
In the U.S., more than 795,000 people have a stroke every year, which amounts to one stroke every 40 seconds.6 While stroke is the second leading cause of death, and a leading cause of disability, worldwide,7 it’s only recently that its link to sleep has become more widely recognized. In fact, most strokes occur in the first hours of the day, a time during sleep when blood pressure patterns dip, then surge in the morning.
“This morning blood pressure surge has been suggested to lead to increased cardiovascular and cerebrovascular events in the morning by disrupting vulnerable plaques, leading to rupture and thrombosis,” researchers explained in the journal Frontiers in Neurology.8
Sleep duration is also associated with an increased risk of high blood pressure, a leading risk factor for stroke. One study revealed, for instance, that sleeping for less than seven or more than eight hours per night is associated with an increased risk of high blood pressure.9
Disrupted sleep, including that caused by sleep apnea or limb movements during sleep, can also raise stroke risk, as noted in the Journal of Stroke,10 perhaps because it puts extra stress on your cardiovascular system:
“Any causes of sleep curtailment or fragmentation such as sleep restriction, sleep apnea, insomnia, periodic limb movements during sleep, and shift work, not only impair cardiovascular restoration but also impose a stress on the cardiovascular system. Sleep disturbances have been reported to play a role in the development of stroke and other cardiovascular disorders.”
In order to reduce your risk of stroke and other chronic conditions, optimizing your sleep is crucial — but what’s the “magic” number? Adults need an average of seven to nine hours of sleep a night, with most doing well with about eight.
