Resting postures such as squatting or kneeling may be better for health because they require more muscle activity than sitting on a chair, researchers claim.

The findings are based on data gathered from a hunter-gatherer population in Tanzania who wore devices that measured physical activity as well as periods of rest.

Anthropologists from the U.S. found that despite being sedentary for almost 10 hours each day, equivalent to clocking a shift in the office at the desk, the Hazda people appeared to lack the markers of chronic diseases associated with long periods of sitting.

They believe this is down to the “active rest postures” used by the tribe. David Raichlen, a professor of biological sciences at the University of Southern California’s Dornsife College of Letters, Arts and Sciences, and lead author on the study, said: “Even though there were long periods of inactivity, one of the key differences we noticed is that the Hadza are often resting in postures that require their muscles to maintain light levels of activity — either in a squat or kneeling.”

Prolonged sitting has been linked to an increased risk of cardiovascular disease and death, but according to the researchers, this contradicts the evolutionary aspect which favors strategies that conserve energy.

Brian Wood, an anthropologist at the University of California, and one of the study authors, said: “Preferences or behaviors that conserve energy have been key to our species’ evolutionary success. But when environments change rapidly, these same preferences can lead to less optimal outcomes. Prolonged sitting is one example.”

To find out more, the researchers looked at the data from 28 Hadza adults who wore devices, known as accelerometers, for eight days and compared it with the information gathered from previous studies that measured inactivity in modern working populations. They found that their test subjects had high levels of physical activity for just over an hour a day alongside several hours of inactivity, between nine to 10 hours a day. But despite remaining in resting postures for long periods of time, the Hazda people did not show any signs of the health conditions associated with a sedentary lifestyle. The researchers said, it is because the squatting and kneeling postures use more muscle movement than sitting on a chair.

Words to Learn 相关词汇

【最佳的】 zuìjiā de optimal most desirable or satisfactory

【加速度计】jiāsùdùjì accelerometer an instrument for measuring the acceleration of a moving or vibrating body

研究人员指出，蹲或跪这样的休息姿势也许更有益健康，因为这些姿势比静坐在椅子上需要更多肌肉活动。

该研究发现基于从坦桑尼亚的一个游猎采集部族收集来的数据，这个部族的人佩戴了装置来测量他们的体力活动和休息时间。

美国的人类学家发现，尽管哈兹达部落的人每天静止不动的时间将近10个小时，相当于在办公桌前上一天班，但他们似乎没有久坐带来的慢性病迹象。

人类学家认为，这是由于该部落采用的“积极休息姿势”。

该研究的主要作者、美国南加州大学多恩西夫文理学院的生物学教授戴维▪瑞奇兰博士说：“尽管哈兹达人静止不动的时间长，但我们注意到一个重要区别：他们经常采用需要稍微运动肌肉来保持的休息姿势 —— 要么蹲着，要么跪着。”

久坐会导致心血管疾病风险增高和死亡，但研究人员指出，这有悖于偏好保存能量策略的进化论。

该研究的作者之一、加州大学的人类学家布莱恩▪伍德说：“保存能量的倾向或行为对于人类进化的成功很关键。”

“但是当环境迅速变化时，这种倾向却不会导致最佳结果。久坐就是一个例子。”

为了进一步了解真相，研究人员查看了来自28名佩戴加速度传感器长达八天的哈兹达成年人的数据，并将其与先前测量现代劳动人口静止状态的研究收集到的信息作比较。

他们发现，他们的测试对象一天从事高强度体力活动的时间刚过一小时，而不动的时间长达数小时，每天有9到10小时的（清醒）时间是静止不动的。但是，尽管长时间保持休息姿势，哈兹达人并没有显现出任何和久坐生活方式相关的健康问题的迹象。

研究人员称，这是因为哈兹达人蹲和跪的姿势比坐在椅子上需要更多的肌肉运动。

(chinadaily.com.cn)