Six months of exercising can reverse age-associated decline in physical condition, according to a new study in September's Circulation.
The study showed even older people who have not stayed fit could benefit from exercise and improve their cardiovascular function.
However, the study also concluded the health benefits of exercise are lost relatively quickly, so "exercise must be a lifelong habit - like brushing your teeth or taking a shower."
As an example of how quickly physical condition deteriorates, twenty-year-olds were given twenty days of bed rest. The negative effect on their cardiovascular health was equivalent to thirty years of aging.
However, an exercise program of moderate intensity was able to reverse the loss of cardiovascular capacity, returning the group to normal.