Can You Nap Your Way to Health?

Siestas and Your Heart: Can You Nap Your Way to Health?
From Harvard Health Publications

Here in the United States, many people consider eight hours an ideal amount of sleep — and most of them expect those eight hours to come in one block at night. But in Latin America, Mediterranean countries, and other parts of the world, the ideal slumber follows quite a different pattern. In sunny climates, people like to retreat from the heat and stress of a busy day for an afternoon siesta, then make up the difference by staying up late at night.

Cultural norms evolve to suit the needs and preferences of particular societies. But human biology is much the same in Athens and Chicago. Perhaps, then, a study of siestas in Greece will help Americans understand their own choices for healthful sleep. The study also raises the interesting possibility that a daily siesta may help ward off heart disease.

The Greek Epic Study

To look for a link between siestas and the risk of heart disease, scientists from the University of Athens Medical School and the Harvard School of Public Health studied 23,681 Greek men and women. All the volunteers were free of diagnosed heart diseases, cancer, and stroke when they enrolled in the study between 1994 and 1999. They all reported on their napping habits; the researchers classified them as regular nappers, occasional nappers, or non-nappers. They also collected information on all the participants’ age, education, smoking status, employment, exercise level, diet, body mass index, and waist-to-hip ratio.

The subjects were tracked for an average of 6.3 years; in this period, 133 members of the group died from coronary artery disease. As expected, advancing age, smoking, and abdominal obesity were linked to an increased risk of cardiac death, while exercise, a good diet, increased education, and gainful employment appeared protective. Surprisingly, though, midday napping was also protective, especially for men.

Among the entire group, siestas of any duration or frequency were associated with a 34% lower risk of dying from heart disease, even after accounting for other risk factors. Occasional napping was linked to a 12% reduction in cardiac mortality, but regular napping appeared to reduce risk by 37%. The apparent protection was stronger for men than women; among working men, occasional nappers were 64% less likely to die from coronary artery disease than their non-napping peers, and regular nappers were 50% less likely to die from coronary artery disease than non-nappers.

Early to bed, early to rise?

Mediterraneans and Latins may be the masters of napping, but Americans may be more likely to observe Ben Franklin’s prescription that “early to bed and early to rise makes a man healthy, wealthy, and wise.” Was Franklin right? A team of Harvard researchers had the temerity to test his dictum. They evaluated 949 men who had been hospitalized with heart attacks. After tracking them for an average of 3.7 years, they found no relationship between early bedtimes (before 11 p.m.) or early awakening (before 6:30 a.m.) and death rates, income, or educational attainment.

It’s still possible, though, that time is money, or that a penny saved is a penny earned.


Wake-up calls

Two earlier studies from Greece support the possibility that midday napping may reduce the risk of heart disease, but a larger study from Costa Rica and two from Israel produced opposite conclusions. Is there something different about Greece, or is there something different about the studies? Without discounting the unique characteristics of the Aegean nation, differences in the research may explain the contradictory results. The new study differed from the others by enrolling only healthy people; it also accounted for the effects of exercise — but the other studies did not. People who are ill often sleep during the day because of exhaustion or fatigue. By including them in the analysis, any benefit of voluntary napping by healthy people could easily be obscured. In fact, the Greek Epic Study reported the greatest benefit among working men.

If siestas are beneficial, how do they work? Stress reduction is the most plausible explanation and would fit with the observation that voluntary midday naps were particularly helpful to working men.

The power(ful) nap

The possible cardiac benefits of napping will require more study. But there are other, well-documented benefits. Studies of shift workers, airline flight crews, medical interns, and highway drivers have all reported that naps as short as 20–30 minutes decrease fatigue and improve psychomotor performance, mood, and alertness. That’s a big benefit to the napper — and to his passengers or patients.

Napping niceties

If you nap, be sure it’s because you want to, not because you have to. Sleep deprivation — from sleep apnea, restless legs syndrome, depression, or any other cause — produces daytime somnolence that may make you need to nap. Sleep deprivation is harmful to your health. If you find yourself nodding off when you least want to, don’t just give in to a nap. Instead, find out what’s wrong with your nighttime sleep, then work to correct it.

A voluntary daytime siesta is a different matter. It can be pleasurable, refreshing, and even healthful. If you do take a nap, try to time it to fit your daily sleep-wake cycle; for most men, early afternoon is best. To preserve your good night’s sleep, don’t nap too long; for most people, 20 to 40 minutes work best. And expect to be a bit sluggish or groggy when you wake up, so give yourself at least 10 minutes to fully awaken before taking on any demanding tasks.

Dream on

The Greek Epic Study raises the possibility that daytime siestas may help reduce the risk of dying from heart disease. Since napping takes less discipline than a good diet and less effort than regular exercise, it’s a hopeful possibility. But confirming studies are needed, and even if the association holds up, observational studies can never prove cause and effect. In this case, for example, siestas might be a marker for an overall healthier lifestyle rather than a unique way to protect your heart.

Remember, too, that it’s easier to nap in Athens, Greece, than Athens, Georgia, particularly for working men. A siesta may reduce stress in Greece, but it may introduce stresses in the United States.

Don’t count on naps to protect your heart — but if you enjoy siestas as part of a healthful lifestyle, nap away. And even if you can’t fit in a nap at work, if you travel to Greece you may be able to do as the Greeks do.