That level of baseline activity could explain why the MICT actually increased the all-cause-mortality risks. It appears the the mixed control group means that the MICT was actually reducing the average exercise intensity from the norm. What a frickin' overachieving set of septuagenarians (reminds me of Mr. Awesome in Chuck)! I'd assume if there were more "no/low" exercise group the MICT would appear much better. Tantalizing results though.

The control group wasn't assigned to do their regular level of exercise, but rather to follow an exercise routine based on the Norwegian government's existing recommendations. The authors expected a 10% 5 year mortality rate based on population-wide estimates, and their control group had a 4.7% 5 year mortality rate.