People who stay even moderately fit as they age may live longer than those who are out-of-shape. Researchers from the University of Otago ( New Zealand) studied 4,384 middle-aged and older adults whose fitness levels were assessed via exercise treadmill tests, then whom were followed for nine years. When the team separated the participants into five groups based on fitness levels, they found that one-quarter of the least-fit men and women had died during the study period, as compared to 13% of those who were slightly more in-shape.