Randomized Controlled Trial of Exercise for Longevity

A critical analysis on whether physical activity is a cause of longevity concluded “the undisputed health-related benefits of exercise have yet to translate into any proven causal relationship with longevity.” This was based on the fact that though randomized controlled trials in clinical populations (suffering mostly from neurological conditions) have shown a drop in premature death rates, exercise interventions have failed to show exercise extends life among apparently healthy individuals. However these are difficult studies to run.  
 
Take the largest such study, where more than 1,500 older men and men and women (average age 73) were randomized to one of three groups for five years: A recommendation to just follow the national guidelines of 30 minutes a day five days a week, or to replace two of those weekly sessions with 50 minute sessions, or to replace two of those weekly sessions with four four-minute bursts of high intensity interval training at 90% of peak heart rate. And, there ended up being no difference in mortality rates between the two extra exercise groups and the control group. This may be because the control group ended up exercising so much. The control group advised to exercise for just 30 minutes ended up exercising more than the group told to boost weekly session up to 50 minutes. All participants had the potential to be randomized to the high intensity group and so the enrollees had to be pretty fit at baseline and with expectations of health checks at years one, three, and five the control group stepped it up so much it blurred the distinctions between the three groups.