as i've been doing more long rides i've been reflecting on my bygone days of being a runner and gosh biking is so much more pleasant
after running a marathon, your body is a wreck. they hand out space blankets because your ability to regulate temperature shuts down. the next couole days you're wobbly. this is even when going at a sustainable, non-race pace
on the flip side, ride a bike for a similar number of hours and you're barely sore. hop back on the next day and do it again, no problem. you can cover hundreds of miles a week! incredible, what a technology
anyway i was trying to answer the question of "what's an equivalent bike ride to a marathon" and based on my own and others' experience i think the answer is just "there's no comparison, biking is so much lower impact that you just can't damage yourself in a day to the extent a marathon does"