An observational Danish study suggests a U-shaped association between all-cause mortality and dose of jogging as calibrated by pace, quantity, and frequency of jogging. Light and moderate joggers have lower mortality than sedentary nonjoggers, whereas strenuous joggers have a mortality rate not statistically different from that of the sedentary group. In the study, 1,098 healthy joggers and 3,950 healthy nonjoggers were prospectively followed up since 2001. Compared with sedentary nonjoggers, 1 to 2.4 hour of jogging per week was associated with the lowest mortality. The optimal frequency of jogging was 2 to 3 times per week or ≤1 time per week. The optimal pace was slow or average. The joggers were divided into light, moderate, and strenuous joggers. The lowest mortality was found in light joggers, followed by moderate joggers and strenuous joggers. However, there is considerable controversy over a dose-response relationship between running and mortality. Larger observational studies suggested that the health benefits of running may accrue up to 30 miles per week. Source: http://content.onlinejacc.org/article.aspx?articleID=2108914; http://atvb.ahajournals.org/content/early/2013/04/04/ATVBAHA.112.300878.abstract丹麦的一项观察性研究表明，经校正速度，数量和频率，全因死亡率和跑步的量之间存在U形相关。轻中度跑步者的死亡率比久坐不动者较低，而剧烈跑步者与久坐不动者的死亡率之间则无统计学差异。该项研究对1098名健康跑步者和3,950名健康久坐不动者从2001年开始进行前瞻性随访。与久坐不动者相比，每周跑1〜2.4小时与最低的死亡率相关。跑步的最佳频率是每星期≤1次或每星期2〜3次。最佳节奏为慢跑或平均水平。跑步者分为轻度，中度和剧烈跑步。轻度跑步者死亡率最低，然后是中度和剧烈跑步者。不过，对跑步和死亡率之间存在的量效关系有相当大的争议。曾有较大的观察性研究提示，跑步对健康的益处累计可高达每星期30英里。来源：http://content.onlinejacc.org/article.aspx?articleID=2108914; http://atvb.ahajournals.org/content/early/2013/04/04/ATVBAHA.112.300878.abstract
