国内英语新闻:Napping may help lower blood pressure: study

LOS ANGELES, March 2 (Xinhua) -- Those who take a nap are more likely to have lower levels of blood pressure despite stress, said a new study in the latest issue of International Journal of Behavioral Medicine available on Wednesday.

In the study, researchers at Sarah Conklin of Allegheny College in Meadville, Pennsylvania examined 85 healthy university students, who were divided into two groups, with one group taking an hour- long nap during the day, and the other group having no time to sleep. Both groups were given a mental stress test.

The study found that participants in both groups experienced increase in blood pressure and pulse rates when they took the stress test, but the average blood pressure of those who slept for at least 45 minutes was significantly lower after the stress test than it was for those who did not sleep.

The researchers drew the conclusion that a daytime nap of at least 45 minutes may help stressed-out people lower their blood pressure and protect their heart.

"Our findings suggest that daytime sleep may offer cardiovascular benefit by accelerating cardiovascular recovery following mental stressors," the researchers said in the study.

"Further research is needed to explore the mechanism by which daytime sleep is linked with cardiovascular health and to evaluate daytime sleep as a recuperative and protective practice, especially for individuals with known cardiovascular disease risk and those with suboptimal sleep quality," they added.

Sleep deficiency is common in the United States, posing a long- term health threat. On average, Americans get nearly two hours less sleep a night than they did 50 years ago, according to background information provided by the journal.