"Please tell me, how frequent do "fitness" or "road" cyclists take rest days?"
I suppose I should have started the thread with that issue.
I am no doctor of medicine, but my simplified understanding is this. Most folks who exercise strenuously and daily, be it road cyclists, runners, or other sports, have to take one or two rest days a week. Otherwise, they eventually get repetitive use injuries to joints and muscles. Most often with cyclists it is knees.
It is not about energy but muscle and soft tissue recovery. It is the same issue with weight lifting, where lifters only lift 3 times a week to allow the muscles to recover. Use breaks down the muscle tissue at the cell level and when that tissue heals it restores at a greater size and strength, which is why muscles get stronger with exercise. Absence of recovery time prevents the restoration process and results in weaker tissue.
If you can forgive any technical omissions or errors in the above, my question is based on the fact that touring cyclists ride day after day for a long time so I assumed they would require a rest day, but I thought the slow pace of touring might make it different. The comments here generally speak of various reasons why they do take a rest day, but they do not sound like they include any need to allow for soft tissue recovery.
I do not tour. I would love to, and have always read what I could in the way of touring stories, but I don't recall hearing anything about rest days. I am just curious why you folks don't seem to need any recovery time for your soft tissue.