This started as a comment to Mark's post, but it got a bit lengthy so I decided to post it here instead.
I am not tracking numbers as you know (training metrics like TSS, CTL, etc.), but the illness that swirls about me on a daily basis (everyone I know has upper respiratory infections), the increase in riding I have been doing, and the feeling I have (like I am on the verge of catching some illness) have me convinced. I am doing some low level (low to moderate) spinning on the rollers these days for a couple reasons.
I could take time off completely, but that results in me not sleeping well. I could continue training like I have been, but that will likely land me in bed recovering from illness (and sleeping poorly as a result of a cold remedy coma/stupor).
I have elected to keep it simple with low intensity. Just enough to keep the blood flowing and release some natural histamines, dopamine, and whatever else my body does as a result of riding that keeps me happy and healthy. These types of rides do not give me a lot to talk about though.
One other reason that I should mention for doing this low level stuff has a lot to do with the reasons Mark points out in his post. I try to make a point of following the advice from someone that has transformed from a strong rider that I used to put the hurts to, into a very strong rider that now puts hurt on me when we ride.
Just what the doctor ordered
Yup, pretty much my recommendation. For me, for you, for anyone who gets to feeling something coming on. You hit the nail on the head, hammer.
-- Mark