権威ある医学雑誌Lancetに掲載された、台湾での４２万人を対象にした８年間の観察研究です。
一般的な運動量のガイドライン「毎日３０分以上」を遵守しなくても、毎日１５分ないし週に９０分の運動で、男女いずれも「運動しない人」に比べて、死亡リスクが１４％減少（３年の寿命延長）し、さらに１００分／日までは１５分／日運動時間の増加ごとに、死亡リスクが４％ずつ低下（癌死のリスクが１％ずつ低下）して、毎日１００分の運動継続者では死亡リスクが４０％低下。逆に全く運動しない人は、もっとの少ない運動量の群（１日あたり１５分）に比べて、死亡リスクは１７％増加という結果です。
抄録しか読めないので、年齢構成や運動の内容（種類や強度）が具体的にはわかりませんし、また平日座りっぱなしで週末にまとめて９０分運動するのと毎日１５分運動するので違いがあるのかどうかもしりたいところなので、原論文入手可能になったらチェックしようと思いますが、いずれにせよ「運動は健康維持に必須であり、無用な安静は毒」であることが、欧米だけでなく東洋人でも裏付けられたという事だと思います。
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ABC World News (8/15, story 9, 0:30, Sawyer) reported, "If you need any more convincing that a little bit of exercise can make a huge difference in your life, here's some powerful new proof: A study in the medical journal Lancet looked at 400,000 people and found just 15 minutes of exercise a day increases life expectancy three years."
The AP
, CDC recommendations
, and guidelines from "other countries recommend that adults get at least a half-hour of moderate workout most days of the week," conducted the study to determine whether "exercising less than the recommended half-hour was still helpful." They asked "about 416,000 Taiwanese adults" how much exercising they "did the previous month" and recorded study participants' "progress for eight years on average." The research team found those who "exercised just 15 minutes a day -- or 90 minutes a week -- cut their risk of death by 14 percent" compared with those who did not exercise; and both men and women "benefited equally" from exercising.
Bloomberg News
(8/16, Bennett) reports that the study found those who exercised for 90 minutes per week were also "14-percent less likely to have died after eight years than those who were inactive." Moreover, every additional "15 minutes of exercise reduced the risk" of death by an "additional 4 percent up to 100 minutes a day, after which there was no additional benefit." Notably, the reduction was "as high as 40 percent for those who exercised most often and most vigorously." The results show that even a "small amount of exercise can lower an individual's risk of death and disease, and a nation's health costs," the study authors concluded. Also covering the study are BBC News
(8/16, Roberts), AFP
(8/16) and HealthDay
(8/16, Preidt).
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The Lancet, Early Online Publication, 16 August 2011
Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study
Dr Chi Pang Wen
MD a
b
†
,
†
, Summary
Background
The health benefits of leisure-time physical activity are well known, but whether less exercise than the recommended 150 min a week can have life expectancy benefits is unclear. We assessed the health benefits of a range of volumes of physical activity in a Taiwanese population.
Methods
In this prospective cohort study, 416 175 individuals (199 265 men and 216 910 women) participated in a standard medical screening programme in Taiwan between 1996 and 2008, with an average follow-up of 8·05 years (SD 4·21). On the basis of the amount of weekly exercise indicated in a self-administered questionnaire, participants were placed into one of five categories of exercise volumes: inactive, or low, medium, high, or very high activity. We calculated hazard ratios (HR) for mortality risks for every group compared with the inactive group, and calculated life expectancy for every group.
Findings
Compared with individuals in the inactive group, those in the low-volume activity group, who exercised for an average of 92 min per week (95% CI 71—112) or 15 min a day (SD 1·8), had a 14% reduced risk of all-cause mortality (0·86, 0·81—0·91), and had a 3 year longer life expectancy. Every additional 15 min of daily exercise beyond the minimum amount of 15 min a day further reduced all-cause mortality by 4% (95% CI 2·5—7·0) and all-cancer mortality by 1% (0·3—4·5). These benefits were applicable to all age groups and both sexes, and to those with cardiovascular disease risks. Individuals who were inactive had a 17% (HR 1·17, 95% CI 1·10—1·24) increased risk of mortality compared with individuals in the low-volume group.
Interpretation
15 min a day or 90 min a week of moderate-intensity exercise might be of benefit, even for individuals at risk of cardiovascular disease.