Paying the Piper

Well, it's finally happened: muscle injuries, plural. Minor ones, but not fun.

In Doing Lake Centennial on a Saturday Morn I told of running the 2.4-mi. loop around a nearby lake at a previously unapproached rate of over 164 — and up to 168 — beats per minute on my heart rate monitor. Never before had I sustained an average HR above the vicinity of 154, ten beats fewer per minute.

Later on that same day, my lower back began to hurt. That was a first since I began my fitness program about five weeks ago.

Then, a few hours after a walk-only outing the next morning, the insides of my calves began to ache. Another first.

Most of the pain in both cases is/was on my body's right side, but there are/were echoes in corresponding places on the left side.

I began taking Aleve, assiduously resting, and icing the affected areas. This morning I was able to do a laid back walk-jog around the same lake with little distress. I took care to stretch my lower back much more carefully than I had been doing in the past.

So I appear to have started to recover already. Although I'm still sore, using ice and Aleve, and resting a lot, I'm better off than I was yesterday.

But I realized yesterday evening that (duhhhh!) I was finally paying the piper for pushing myself well above my actual exercise capacity. I can do 154-bpm jogs without repercussions; I can't sustain 164-bpm jogs. I've learned my limit.

Notice I say "jogs." Not "runs." They're not even "jogs," per se; they're "slow jogs." Grandma Moses would pass me by, if she were still around.

My slow jogs which produce such high heart rates, quite near my measured maximum of 170 bpm, do not make me winded or overly sweaty. They make me feel great, both during and after. The only thing is, my heart rate goes up real high: into the 90%- or 95%-of-maximum range. 90% (153 bpm), I find I can hack. 95% (161 bpm) and above trigger repercussions.

And the literature confirms my experience: exercising above one's 90% level is supposed to involve an increased threat of injury. That's one reason why exercisers are supposed to stay below 90%.

So the question is, why do I get such high heart rates with slow (by the standards of 99% of the other joggers I encounter) exercise that doesn't leave me anywhere near being doubled over, trying to suck in more air?