ok so I served a mission about 10 years ago.
yes there is 30 mins of exercise time baked in in the morning, but 95% of the time it was not used or people did a few pushups etc.
the schedule was strict. by 8am you had to be ready to study with your companion and out the door by 9 or 10am. with showering, breakfast, personal study etc, there was little wiggle time. there was no "sleeping in" in the mission either, so many used that exercise time to get an extra 30 mins of cheat sleep.
you had to within eyesight of your missionary "companion". this was strictly followed by everyone. so unless your companion (who is randomly assigned), was a good runner, you were not running. imagine getting posted to live with some random guy at the workplace...what the odds he is willing to run 5 miles at 630am every morning with you?
many areas i served in running simply didnt work. it was either a traffic filled hellhole with no place to run or deep in some rural area with 2 foot snow drifts.
I was also tired all the time. so much walking.
and this might come as a shock to many here, but I was focused nearly 100% on the missionary work, and something like running simply was not a priority (i ran track at a service academy school).
towards the end of my mission, as I was getting ready to be back in school soon (and service academy), I got some permission to take my missionary companion to run at the local track a few times a week outside the 630am time slot to get some laps in to get me ready for post mission life. I was extremely out of shape (running one mile made my lugs burn). This just helped me not be totally inept/fat.
took me several months after my mission to feel like I could "train" again. after about 6 months, I was feeling a LOT better.