This paper provides another example of the influence of exercise on life span, even in the old. In statistical human studies all you can usually show are associations, but it is clear from animal studies in shorter lived species that there is a causative link between regular exercise and healthy life expectancy.
There has been extensive research showing that among generally healthy, cancer-free populations, physical activity extends longevity. But there has been relatively little such research on physical activity among cancer survivors. Researchers examined data from the Harvard Alumni Health Study, an ongoing study of men who entered Harvard as undergraduates between 1916 and 1950. Researchers looked at 1,021 men (average age 71) who previously had been diagnosed with cancer. In questionnaires conducted in 1988, men reported their physical activities, including walking, stair-climbing and participation in sports and recreational activities. Their physical activities were updated in 1993, and the men were followed until 2008.
Compared with men who expended fewer than 2,100 calories per week in physical activity, men who expended more than 12,600 calories per week were 48 percent less likely to die of any cause during the follow-up period. This finding was adjusted for age, smoking, body mass index, early parental mortality and dietary variables. (By comparison, a 176-pound man who walks briskly for 30 minutes a day, five days a week burns 4,200 calories.) There were similar findings for mortality from cancer and cardiovascular disease: the most physically active cancer survivors were 38 percent less likely to die of cancer and 49 percent less likely to die of cardiovascular disease during the follow-up period.