Dropping Some Science on your Ass...

Medical News today has an interesting, albeit somewhat technical article, Ironman Study Redefines Fine-tuned: Balance Training Time With Blood Pressure Variability
The gist of it is that Ironman competitors with the most training time per week have the fastest times, and the have the fastest recovery times. From the article:
For the largest part, namely for the 5 million years of the hunter-gatherer age, mankind had to perform daily a regimen of 10-30 km of walking and running for survival. This would correspond to up to 4 hours daily exercise time and a WNET of 28 hours. Our ‘well-trained' athletes achieved only between 20%-60% of this duration of training, which demonstrates the change of perspective that occurred with the beginning of the industrial age.