It is well known that regular physical activity is associated with a reduced risk of non-communicable disease morbidity and premature death.
The WHO 2020 guidelines on exercise and sedentary behavior recommend that adults should do at least 150-300 minutes of moderate-intensity aerobic exercise or at least 75-150 minutes of vigorous-intensity aerobic exercise per week, or equivalent moderate-intensity and vigorous-intensity exercise combined with [1].
More and more people are doing sports in their leisure time to maintain their health [2-3]. However, it is unclear whether chronically higher levels of vigorous-intensity and moderate-intensity exercise are associated with lower mortality .
Recently, Dong Hoon Lee's team at the Harvard School of Public Health answered this question. They found that 300-600 minutes of moderate-intensity exercise or 150-300 minutes of high-intensity exercise per week, or an equivalent combination of the two, had the lowest risk of death . The results of this study were published in the famous journal Circulation [4].
So, my friends, if we want to live a long life, we need to strengthen our physical activity !
Previous studies have shown that with the same total amount of exercise, a higher proportion of high-intensity exercise to total exercise is not associated with lower all-cause mortality [5].
However, in a large prospective study, a higher proportion of high-intensity exercise was associated with a lower risk of death for the same total amount of exercise [6]. There are also studies that have come to the exact opposite conclusion, and some studies in runners have shown that excessive high-intensity exercise has adverse effects on cardiovascular disease (CVD) [7-9]. These findings suggest that the health benefits of physical activity may vary by intensity and duration .
These studies have certain limitations, including small study population, short follow-up time, and insufficient covariate information. In this study, Dong Hoon Lee's team included data from two large prospective cohorts of NHS (Nurses' Health Study) and HPFS (Health Professionals Follow-Up Study) with a total of 116,221 participants.
During the 30-year follow-up , the researchers performed more than 15 detailed repeated measures of participants' self-reported physical activity, which could minimize reverse causality and individual measurement errors, and analyze the relationship between long-term physical activity of different intensities and overall Association between death due to cause and cause-specific mortality.
In order to quantify the intensity of physical exercise, the research team defined metabolic equivalent (MET), 1MET=1kcal/kg/hour, which is a person's resting sitting metabolic level [10]. Sports with exercise intensity <6 METs are defined as moderate-intensity exercise, including walking, low-intensity physical exercise, weightlifting, and aerobics. Physical activity with exercise intensity ≥6 METs was defined as high-intensity exercise, including jogging, running, swimming, cycling, other aerobic exercises, playing squash/squash or tennis, outdoor work, climbing stairs, etc. Moderate-intensity exercise and high-intensity exercise are calculated based on the duration of different-intensity exercise each week.
总体来看，参与者平均年龄为66岁，平均BMI为26kg/㎡。参与者没有严重的慢性疾病如心血管疾病和癌症等，大多数参与者是白人，63%为女性，在随访期间共报告47596例死亡。高强度运动占比较高的参与者较年轻，高强度运动或中等强度运动较高的参与者更瘦，酒精摄入量和饮食质量评分较高，吸烟率较低。
具体来看，与没有长期高强度运动习惯的参与者相比，每周保持75-149分钟高强度运动的参与者全因死亡风险降低19%，CVD死亡风险降低31%，非CVD死亡风险降低15%。
2-4倍于指南建议运动量（高强度运动300-599分钟/周）的参与者死亡风险进一步降低，全因死亡风险降低约21%-23%，CVD死亡风险降低27%-33%，非CVD死亡风险降低19%。不过，更高水平的运动量（高强度运动≥300分钟/周）没有进一步降低死亡风险。
在长期中等强度运动方面，每周保持150-224和225-299分钟中等强度运动的参与者的全因死亡风险分别降低了20%和21%，CVD死亡风险分别降低22%和25%，非CVD死亡风险分别降低19%和20%。
2-4倍于指南建议运动量（中等强度运动300-599分钟/周）的参与者死亡风险进一步降低，全因死亡风险降低26%-31%，CVD死亡风险降低28%-38%，非CVD死亡风险降低25%-27%。
对高强度运动和中等强度运动的联合分析中，研究团队发现在长期中等强度运动不足的人群中，高强度运动与全因死亡和特定原因死亡率之间存在很强的负相关，在长期中等强度运动达标的人群中这一反向关联较弱。
在≥2倍指南建议中等强度运动运动量的人群中，高强度运动与全因死亡和特定原因死亡率之间没有明显的负相关。此外，这种负相关在BMI较低的个体中较明显。
研究团队进一步分析了高强度运动占总运动量的比例对全因死亡和特定原因死亡风险的影响，发现与缺乏高强度运动的参与者相比，有高强度运动的参与者的全因死亡率和因特异死亡风险都较低。然而，高强度运动占比超过25%后，死亡风险未进一步降低。
在运动不足（1-149分钟/周）或刚满足指南建议运动量（150-299分钟/周）的人群中，增加高强度运动比例有利于降低死亡风险。不过，在≥2倍指南建议运动量的参与者中，增加高强度运动比例不会使死亡风险进一步降低。
另外，对CVD相关事件的分析表明，与没有高强度运动习惯的参与者相比，达到指南推荐高强度运动运动量（75-149分钟/周）的参与者CVD风险降低22%，冠心病风险降低25%，卒中风险降低14%。达到指南推荐中等强度运动运动量（150-299分钟/周）的参与者CVD、冠心病和中风的风险降低5%-11%。2-4倍于指南建议高强度运动或中等强度运动运动量的参与者，心血管疾病和冠心病的风险进一步降低。
总的来说，通过分析两个大型前瞻性队列研究的数据，研究团队发现每周2-4倍于指南推荐运动量，即300-600分钟中强度运动或150-300分钟高强度运动或两者的等效组合，死亡风险最低。
在长期更高水平的高强度运动或中等强度运动人群中并没有观察到全因死亡风险、CVD死亡风险和非CVD死亡风险的进一步降低。此外，对于中等强度运动＜300分钟/周的参与者，高强度运动增加与较低的死亡风险相关，在中等强度运动≥300分钟/周的参与者中，高强度运动增加对死亡风险的影响不大。
参考文献
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