The NYT discusses a pair of health studies showing that "a person's fitness level at midlife is a strong predictor of long-term heart health, proving just as reliable as traditional risk factors like cholesterol level or high blood pressure:"
"When you try to boil down fitness, what does fitness mean?" said Dr. Jarett D. Berry, assistant professor of internal medicine and cardiology at Southwestern Medical School and a co-author of both papers. "In both these studies, how fast you can run in midlife is very strongly associated with heart disease risk when you're old. The exercise you do in your 40s is highly relevant to your heart disease risk in your 80s." [...]
From the study data, Dr. Berry calculated that a man in his 50s who can run a mile in 8 minutes or less, or a woman who can do it in 9 minutes or less, shows a high level of fitness. A 9-minute mile for a man and 10:30 for a woman are signs of moderate fitness; men who can't run better than a 10-minute mile, and women slower than 12 minutes, fall into the low-fitness category.
The categories make a big difference in risk for heart problems, the study found: Subjects in the high-fitness group had a 10 percent lifetime risk, compared with 30 percent for those in the low-fitness group.