My question is about good cues for avoiding overtraining.
Background: I started running regularly just under a year back and run for fun. I have poor speed and endurance even for a hobby jogger, but that doesn’t bother me. I do get injuries from time to time, almost certainly because of my running, and want to avoid them.
Recently, I started running with a heart rate range of 140-160 (resulting in an average of just under 150 usually). My max HR is ~190. I started doing this because I realized that no matter how slow I jogged, my HR would usually climb up to ~170 if I jogged continuously. I also realized that if I took brief walking breaks, my runs are just more economical, i.e., lower HR for the same average pace (including walk breaks) or faster pace for the same HR.
Previously, I would run 15-20 mpw and run 3-5 times a week. With the rangebound HR runs, I’m running 4+ miles every single day (although 20-25% of it is walking). But suddenly seeing 30 mpw on my watch gives me pause as it’s a significant increase. On the other hand, running at 150 HR feels good and I’m rarely sore later in the evening or the next day from the run. When I was running continuously earlier, I’d often be sore especially after harder or longer run days.
Question: Is a sudden increase in mileage by itself bad even if I’m feeling fine after the runs? Other than mileage itself, what cues do you use to know that you are overtraining?
PS: I’m aware of the too often cited 10% rule but feel like it’s not useful when you don’t know what the first week mileage should be. My low HR running just feels like a different kind of running than my previous running, so I’m not sure the mileages are comparable, but am also nervous for the same reason.