柳叶刀:久坐8小时“危险”,运动1小时“好啦”
2016/08/04
对很多上班族来说,每天“静坐”8小时以上已经成了家常便饭。这样的生活习惯非常不利于身体健康。今天小编为大家带来一则好消息。日前,发表在国际顶级医学期刊《柳叶刀》上的一项研究发现,每天运动1小时能够消除静坐8小时带来的健康风险。


过去的几十年里,科学家们发现,越来越多的证据表明,缺乏身体活动是多种疾病的主要风险,也会导致过早死亡。据估计,每年全球有超过500万人因未到达建议的活动水平而死亡。

目前的身体活动指南建议,成年人每周至少要做150分钟中等强度的运动。而事实上,许多人的一天是这样度过的:开车去上班、坐在办公室、开车回家、坐下看电视。那么,足够的活动量是否能够降低或者抵消久坐带来的风险呢?

运动1小时 KO 久坐8小时

7月27日,发表在《柳叶刀》(The Lancet)杂志上的一项研究发现,每天运动1小时或更多时间能够消除每天坐8小时或更久带来的健康风险。

这一荟萃分析包括了16项研究,涉及的参与者超过100万。根据中度身体活动的水平,研究人员将他们分为4组。中度运动的定义相当于以5.6公里/小时的速度行走,或者以16公里/小时的速度骑自行车。


Ulf Ekelund教授

结果发现,每天中度运动60-75分钟,足够消除每天静坐超过8小时增加的早逝风险。该研究的通讯作者、剑桥大学的Ulf Ekelund教授表示,这背后的生物学机制尚不清楚,但动物研究表明,缺乏运动与某些激素的产生减少相关。

他说:“对很多人来说,因为在办公室工作等原因,很难逃避长时间的静坐。对他们而言,运动是非常重要的,比如午餐时间出去散步、晨跑或者骑车上班。”

理想的情况是每天运动1小时,但如果无法做到,至少每天要尽可能做一些运动帮助降低久坐带来的风险。人们可以将每天所需的运动时间拆分开,如每个小时步行5分钟。

局限性

研究人员也承认,这些数据分析存在一定的限制性,这主要与参与者的年龄(> 45岁)和所在国家(来自美国、西欧和澳大利亚)有关。然而,他们相信,这一分析的价值要超过它的局限性。更重要的是,这一科学家小组要求荟萃分析中包含的所有研究都以一种统一的方式重新分析了原有的数据。这种方式在此类规模的研究中从未用过。

备注:本文编译自Medicalxpress(An hour of moderate exercise a day enough to counter health risks from prolonged sitting)以及Medscape(One Hour of Activity Offsets Risks From 8 Hours of Sitting)。

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  • Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women

    Background High amounts of sedentary behaviour have been associated with increased risks of several chronic conditions and mortality. However, it is unclear whether physical activity attenuates or even eliminates the detrimental effects of prolonged sitting. We examined the associations of sedentary behaviour and physical activity with all-cause mortality. Methods We did a systematic review, searching six databases (PubMed, PsycINFO, Embase, Web of Science, Sport Discus, and Scopus) from database inception until October, 2015, for prospective cohort studies that had individual level exposure and outcome data, provided data on both daily sitting or TV-viewing time and physical activity, and reported effect estimates for all-cause mortality, cardiovascular disease mortality, or breast, colon, and colorectal cancer mortality. We included data from 16 studies, of which 14 were identified through a systematic review and two were additional unpublished studies where pertinent data were available. All study data were analysed according to a harmonised protocol, which categorised reported daily sitting time and TV-viewing time into four standardised groups each, and physical activity into quartiles (in metabolic equivalent of task [MET]-hours per week). We then combined data across all studies to analyse the association of daily sitting time and physical activity with all-cause mortality, and estimated summary hazard ratios using Cox regression. We repeated these analyses using TV-viewing time instead of daily sitting time. Findings Of the 16 studies included in the meta-analysis, 13 studies provided data on sitting time and all-cause mortality. These studies included 1 005 791 individuals who were followed up for 2–18·1 years, during which 84 609 (8·4%) died. Compared with the referent group (ie, those sitting <4 h/day and in the most active quartile [>35·5 MET-h per week]), mortality rates during follow-up were 12–59% higher in the two lowest quartiles of physical activity (from HR=1·12, 95% CI 1·08–1·16, for the second lowest quartile of physical activity [<16 MET-h per week] and sitting <4 h/day; to HR=1·59, 1·52–1·66, for the lowest quartile of physical activity [<2·5 MET-h per week] and sitting >8 h/day). Daily sitting time was not associated with increased all-cause mortality in those in the most active quartile of physical activity. Compared with the referent (<4 h of sitting per day and highest quartile of physical activity [>35·5 MET-h per week]), there was no increased risk of mortality during follow-up in those who sat for more than 8 h/day but who also reported >35·5 MET-h per week of activity (HR=1·04; 95% CI 0·99–1·10). By contrast, those who sat the least (<4 h/day) and were in the lowest activity quartile (<2·5 MET-h per week) had a significantly increased risk of dying during follow-up (HR=1·27, 95% CI 1·22–1·31). Six studies had data on TV-viewing time (N=465 450; 43 740 deaths). Watching TV for 3 h or more per day was associated with increased mortality regardless of physical activity, except in the most active quartile, where mortality was significantly increased only in people who watched TV for 5 h/day or more (HR=1·16, 1·05–1·28). Interpretation High levels of moderate intensity physical activity (ie, about 60–75 min per day) seem to eliminate the increased risk of death associated with high sitting time. However, this high activity level attenuates, but does not eliminate the increased risk associated with high TV-viewing time. These results provide further evidence on the benefits of physical activity, particularly in societies where increasing numbers of people have to sit for long hours for work and may also inform future public health recommendations.

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