Again, don't get me wrong. Every study concludes that there's benefit to be gained just by doing something , whether leisurely, moderately or intensely. But consider my home bound patient last week who spins here little cycle for 5-10 minutes/day; she really hasn't improved beyond that stage because she hasn't pushed herself. Why? No one told her to do so! No one gave her a (new) goal! When she first started, 5-10 minutes might as well have been 5-10 hours. But she's been stuck in a rut for the past several months, essentially cruising along at a performance plateau.
If you're still with me, a prospective observational study was published early online in Archives of Internal Medicine in which the authors concluded that cardiorespiratory fitness (as measured by metabolic equivalents (METs) during an exercise treadmill test) in healthy middle-aged adults was linked to better health & lower risk of chronic diseases over a quarter century later. They arrived at their conclusion by analyzing 18,670 disease-free participants avg 46-52yo at baseline in the Cooper Clinic Longitudinal Study and again upon becoming eligible to receive Medicare benefits at 65yo and beyond.
Those men and women who were the most fit at 14.1 & 11.0 METs, respectively, compared to the least fit at 8.5 & 6.4 METs, respectively, had lowest risk for any one or more chronic diseases: ischemic heart disease, stroke, diabetes, chronic obstructive pulmonary disease, chronic kidney disease, Alzheimer disease, and colon+lung cancer.
Bottom line: just walking on the treadmill is better than sitting in front of the TV. But pushing your abilities to reach 11-14+ METs leads to health dividends that pay out a quarter century later. So start investing in your health and keep your goal in mind: healthy aging!