COLUMBIA, SC -- A new study in the Journal of the American Medical Association shows that fitness level, not body fat, is a stronger indicator in judging longevity for older adults.

Exercise expert Steven Blair of the University of South Carolina and his colleagues tracked more than 2,600 men and women age 60 and older, examining how physical fitness and body fat affected their death rates over 12 years. The participants’ fitness was gauged by using a treadmill test, seeing how long they could walk while the treadmill’s incline increased. The researchers also measured body mass index, waist circumference and body fat percentage.

Those participants in the lowest fifth in terms of fitness had a death rate four times higher than those ranked in the top fifth of fitness.

“Being fit provides protection against mortality in these men and women 60 and older, whether they’re normal weight, overweight or obese,” Blair says.

The study also showed that even a modest effort to improve physical activity can provide health benefits. Those in the bottom fifth in terms of fitness were about twice as likely to die than those in the next fifth.

“You shouldn’t be scared and think, ‘Oh, I’m overweight, I’m obese, it’s useless for me to be physically active,” says Dr. Xuemei Sui, another University of South Carolina researcher.

Blair adds, “If you’re overweight or obese and you’re sedentary and unfit and you start taking three 10-minute walks a day, and you do that at least five days a week, you’re not going to lose an enormous amount of weight. You’re still going to be heavy. But you’re going to be much healthier if you do that.”