Is taking a nap really good for your health? Recommended nap length explained
Park Chang-bum, professor of cardiology / Courtesy of Kyung Hee University Hospital at Gangdong
Following your natural biological rhythm and getting proper sleep are excellent ways to maintain your body in good condition — and taking a nap can be part of that.
A short nap when feeling tired can relieve fatigue and improve performance and concentration. But is napping truly beneficial for health? And if so, how long should a nap be?
A study that tracked adults aged 35 to 70 across 21 countries for an average of 7.8 years found that people who slept less than six hours at night and took naps of less than one hour had a 10 percent lower risk of cardiovascular and cerebrovascular diseases and those who napped more than one hour had a 20 percent lower risk, compared to those who slept six to eight hours at night without napping.
However, among those who slept more than six hours at night, taking naps of less than one hour increased the risk of cardiovascular diseases by 10 percent and naps of more than one hour increased the risk by 30 percent. The results suggest that additional napping after sufficient nighttime sleep may not be beneficial.
A meta-analysis of studies on naps and health shows that the relationship follows a J-shaped curve. Among middle-aged and elderly individuals, taking a 30-minute nap daily was associated with a lower risk of cardiovascular and cerebrovascular diseases. However, naps longer than 30 minutes were linked to increased health risks. This trend was more prominent among men and people over the age of 65.
Why are naps under 30 minutes beneficial, while naps lasting over an hour are not? Short naps help improve circadian rhythm and endocrine function in people with sleep deprivation, lowering blood pressure and stress levels.
On the other hand, naps longer than one hour can disrupt sleep and wake cycles, making it harder to achieve deep sleep at night. Chronic poor sleep can, in turn, negatively affect overall health. Some individuals who habitually take long naps were found to have conditions like sleep apnea or chronic obstructive pulmonary disease (COPD).
Sleep apnea, a disorder where breathing stops intermittently during sleep, significantly increases the risk of acute myocardial infarction and stroke. COPD, which involves a gradual decline in lung function, often due to smoking or air pollution, also raises the risk of respiratory failure and heart disease.
For those who do not get enough sleep at night, a nap of less than 30 minutes can be like a tonic. However, naps longer than one hour are not beneficial. If you still feel tired despite sufficient nighttime sleep or find yourself frequently taking long naps, it is advisable to visit a hospital to check for underlying conditions like sleep apnea or COPD.
Moreover, long naps could contribute to insomnia. If you suffer from insomnia, it is important to avoid napping. Taking long naps after a sleepless night can create a vicious cycle, making it harder to sleep the following night. If necessary, try taking a light nap of under 30 minutes.
Waking up suddenly from a deep nap can cause sleep inertia, a condition where grogginess and impaired cognitive function can last for 15 minutes to over an hour. Sleep inertia can reduce alertness and work efficiency even after waking.
This article from the Hankook Ilbo, the sister publication of The Korea Times, is translated by a generative AI system and edited by The Korea Times.