Sleep Is Good for Your Heart

But too much or too little is bad for your heart.

Posted Nov 01, 2019

What are you doing to prevent a heart attack? Perhaps you do the things cardiologists typically recommend: exercise, eat less saturated fat, take statins and omega-3 supplements. Now, there is another recommendation: get 6-9 hours of high-quality sleep each night.

One recent report of over 400,000 people who were evaluated over seven years revealed that people who slept 6-9 hours a night had a 20 percent lower risk of a heart attack than people who slept less. However, sleeping more than 9 hours had a 34 percent higher risk.

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Source: Unsplash

Napping also seems to be a good idea. A group in Switzerland just reported from 3,462 people that those who had two or more naps a week had significantly less cardiovascular disease than those who did not nap. The benefit was unrelated to the length of napping.

The reason sleep is beneficial has not been established, but two lines of reasoning could explain it. The heart gets a rest during sleep. Heart rate and blood pressure typically go down during sleep. Also, sleep gives us a break from the stressful events of the day, events that release hormones and activate the "fight or flight" system that puts a strain on the heart.

As to the paradox of the harmful effects of too much sleep (i.e., greater than 9 hours), one possible cause is too much dreaming, which is tied to the amount of sleep. During dreaming, blood and heart rate can spike, depending on the nature of what one is dreaming about. The incidence of unpleasant, and therefore stressful, dreams should increase with increasing amounts of sleep time. By the way, I published a theory that dreaming is the brain’s way to tell itself it has had enough sleep, and it is time to wake up.

Another cause of excessive sleep can be poor quality sleep. For example, insomniacs may need more sleep, because they are not getting enough good, restful sleep.

Sleep apnea is a proven cause of bad sleep. Apnea is extremely stressful and can raise blood pressure on a continual basis, even during wakeful hours.

So, sleep well, with pleasant dreams. If your dreams are disturbing, program your brain to stop that. Tell your brain its job is to nurture you, not beat up on you (see my Psychology Today post on "How Nightmares May Affect Us, and What We Can Do About It").

References

Daghlas, I. et al. (2019). Sleep duration and myocardial infarction. J. Amer. College of Cardiology. 74, 1304-1314.

Häusler, N. et al. (2019). Association of napping in incident cardiovascular events in a prospective cohort study. Heart. doi: 10.1136iuheartjnl2019-314999 (Sept. 9)

Klemm, W. R. 2011. Why does REM sleep occur? A wake-up Hypothesis. Frontiers in Neuroscience. 5 (73): 1- 12. Doi: 10.3389/fnsys.2011.00073