Dear Doctors: I recently watched a video on the positive effects of napping in regard to heart disease. I am 66; I am a lifelong athlete with normal blood pressure and an LDL cholesterol level that is slightly elevated. I’ve been considering a statin and now wonder how napping may affect that decision.
Dear Reader: The physical benefits of a nap are woven into humankind’s earliest history. Medical texts uncovered in ancient China cite napping as a way to restore balance to the body. In Hellenic Greece and ancient Rome, an afternoon nap was an important health practice. Modern-day researchers are also taking a keen interest in the effects of a daytime snooze. After more than four decades of inquiry, though, the conclusions are mixed.
Some studies, such as those referred to in the video you shared with us, found that napping can have a beneficial effect on cardiovascular health. Others have linked the practice to certain health risks. The reason for these contradictions lies in the complexities of sleep patterns and cardiovascular conditions, and the mechanisms of the studies themselves.
Let’s start with the specific research you are asking about. A study in Switzerland looked at health data from 3,500 adults. The study found that people who napped once or twice a week had a 48% lower risk of cardiovascular disease than those who didn’t nap. Another study, from researchers in Greece and the Harvard School of Public Health, analyzed health data from 23,000 Greek adults. They found that those who took a nap of at least 30 minutes three times a week were less likely to die of heart disease than those who never napped.
And now, the flip side of the coin. Studies have associated daytime napping with an increase in biomarkers of inflammation, impaired blood sugar control, unhealthy blood pressure, sleep disruption and an increased risk of cardiovascular disease. These adverse outcomes are sometimes linked to long daily naps. Others suggest a habit of long naps may be an early marker of cognitive decline. All of the research makes clear that age, health, fitness, genetics and lifestyle also play a significant role.
It is also important to note these are observational studies. These studies extrapolate conclusions from existing health data and not from direct experimentation. An observational study can suggest a correlation between certain factors, but it can’t prove or explain it. When it comes to the effects of napping on cardiovascular health, both sides of that equation are incredibly complex.
Sleep is made up of multiple stages, each with a distinct physiological effect on the body. The development and manifestation of cardiovascular disease is influenced by genetics, diet, environment and lifestyle choices. All of this makes it impossible to make a definitive statement regarding napping and cardiovascular health.
When it comes to napping for improved health, the consensus appears to be that brief naps a few times a week can have a beneficial effect. However, longer naps, particularly for people who are already struggling with overnight sleep, may be associated with cardiovascular risks.
(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
