Karl Michaëlsson and his team at Uppsala University in Sweden surveyed 2,205 men at the age of 50 years, and then again when the participants were 60, 70, 77, and 82. They were asked about their exercise routines and other physical measures like blood pressure, cholesterol, and cigarette and alcohol consumption.
The most intriguing result was that the mortality rate of men who didn't begin exercise until 50 years of age 'caught up' to men who had been exercising their whole lives.
As expected, those who were the most active lived the longest, while those with the most sedentary lifestyles were the most likely to die during the duration of the study. But the most intriguing result was that the mortality rate of men who didn't begin exercise until 50 years of age "caught up" to men who had been exercising their whole lives. The only catch was that it took at least five years for this outcome to take effect — in other words, after only five years of exercise, mortality rates of the newly-fit were still higher, but after ten years, mortality rates were indistinguishable from those who had been exercising all along.
What's more, the study found that the increase in life-span seen in those who began exercise in midlife was almost identical to that experienced by smokers who kicked the habit.
What exactly is the benefit of making these life changes? People who started exercising the most regularly at age 50 increased their life-spans by an average of about 2.3 years; those who added a moderate level of exercise added about 1.1 years to their expected life-span. Both numbers represent comparisons to men who said that they exercised the least.
Do the same results hold true for women? Michaëlsson says that although technically the results cannot be applied to women since they were not included in the study, he does add that he "cannot see a biological reason why there should be gender differences in effect." In other words, there is probably no drawback to adding moderate exercise to one's daily routine, if one is able, as it will likely improve not only quality of life but longevity as well.