All subjects had been referred for clinical treadmill tests and had normal exercise ECG responses and no history of cardiovascular disease. They were classified for fitness by clinical characteristics, physical activity patterns, and treadmill test results. But it was whether the subject reported recent recreational physical activity that predicted mortality. "Reduced physical activity patterns rather than differences in clinical characteristics contribute to the striking difference in mortality rates between the least-fit and the next-least-fit quintile of fitness in healthy individuals," the study concluded.
How much exercise do you need? The difference in this study between least fit and most fit were less than 5.9 METs vs. 6.0-7.9. "Nearly two-thirds of the least-fit individuals were not meeting the minimum recommended amount of physical activity (at least 150 minutes per week, or 30 minutes per day, five days per week)," says the American College of Sports Medicine in a press release.
Source: MANDIC, SANDRA; MYERS, JONATHAN N.; OLIVEIRA, RICARDO B.; ABELLA, JOSHUA P.; FROELICHER, VICTOR F. "Characterizing Differences in Mortality at the Low End of the Fitness Spectrum," Medicine & Science in Sports & Exercise. August 2009 - Volume 41 - Issue 8 - pp 1573-1579
ACSM Press Release, Mortality Linked to Physical Activity Levels in Unfit Individuals," July 30, 2009.