I didnt even realize I started this thread. How time has passed.
Without training, I was able ro run 5 km in 17 min 10 years ago. Was playing a ton of football, but still.
Today, I went for my first run in YEARS without having done any sport like basketball, football, tennis etc. that could help me. Basically I only rode my bike.
It was obnoxiously bad. 5 km, 30 min. I honestly didn't feel like I could go any faster, my legs were completely exploded already in the first km. My HR was completely fine as I would have suspected.
Ill try to go on a few of those 5 km runs a week and in a month, I should be able to do 5 km, 25 min. Hopefully! Always felt that going around that mark is decently acceptable when youre not running a ton.