The Army. A lot of studies are done on high-level, competitive NCAA / college athletes. Both cuz they're, like, already at a university, but also NCAA has man

The Army. A lot of studies are done on high-level, competitive NCAA / college athletes. Both cuz they're, like, already at a university, but also NCAA has mandatory physicals, and high level athletics lends itself to controlled lifestyles. Both tend to rule out most health issues as well; in theory you can be diabetic and play NCAA Div 1 ball, but selection bias tends to weed them out, while the Army explicitly does so.