Thursday, 17 July 2014
The Chinese midday nap causes high blood pressure
The common Chinese habit of having a midday nap - or wujiao (午觉)- is bad for blood pressure, researchers from Wuhan have shown.
In a study of blood pressure levels in more than 27,000 people, Dr Wang Youjie and colleagues from the School of Public Health, Tongji Medical College, Wuhan found that those taking daytime naps had significantly higher blood pressure than non-nappers. The risk of hypertension was directly related to the length of the midday nap, with those napping for more than 30 minutes being at significantly higher risk.
Writing in the Journal of Hypertension, Dr Wang said taking daytime naps could result in the elevation of evening cortisol levels, which may lead to high levels of blood pressure. The increased risk of hypertension in people who nap might also be related to sleep apnoea, the researchers suggested. They noted that midday napping is a also a risk factor for diabetes mellitus
"We postulate that midday napping might increase the risk of diabetes and hypertension
through the mediation of pathophysiological pathway(s) underlying metabolic syndrome, such as insulin resistance or increased inflammation," they said.
Dr Wang noted that napping is a common habit in China, ingrained from childhood, and practised by 80% of Chinese college students, even though it is "more a habit than a
physiological need", according to a recent survey.
"Considering that midday napping is a common practice, these findings have important implications for further investigation of the potential health consequences of napping and of the optimum nap regimen for elderly people," they concluded