Last Sunday was my birthday. Forty-two years old. That makes forty-one years of running. To celebrate, I ran a nice, slow twelve miles.
Truth be told, it didn’t feel as “nice” as I would have liked. If I were really celebrating, I would have gone faster.
But I’m committed to going slower most of the time so that I can stay healthy. And so I can eventually go faster – a seeming contradiction that kept me from running slowly the last twenty years.
For much of my running life, I’ve gone way too fast on my daily runs. Without getting too deep into pace charts, I don’t think I ever ran much slower than my marathon pace; most of my runs were probably somewhere around my 10k pace. Distance didn’t matter too much, I hit the pavement the same way each day.
I’ve worn a heart rate monitor for years, but only out of casual interest. If I did anything with it, it was to make sure my average heart rate for a run wasn’t too low. I wanted to make sure I was working, you know?
Until this spring. Maybe it was all the other health issues I was having, or just a sudden realization that I was moving well past forty, but I realized I wasn’t going to get any faster unless I could get faster at a lower heart rate.
Enter Maffetone. As in Phil Maffetone, and his idea that one should build a base by running at a low heart rate. For me, according to his system, this would be no higher than 139. My typical runs had my heart rate sitting over 150, and I could imagine how slow this would have me going.
This seemed insane to me when I had encountered it in previous years. I’ll lose my mind, I thought, running that slowly. I hate running slowly, I thought. After all, it was the reason I haven’t really run with my wife in the last fifteen years. And she’s not even that slow.
I read more deeply into it, though, and encountered some of the science I hadn’t before. Apparently, running in this zone is what allows muscles to grow mitochondria and for capillaries feeding the muscles to grow and multiply. In that way, aerobic capacity grows and pace will eventually increase at those lower heart rates, and presumably at higher rates too.
What this meant for me was that all my previous attempts to slow down a little bit had probably been completely in vain. I would slow down fifteen or twenty seconds a mile, but would still be sitting in the same zone, not allowing my muscles to grow and adapt aerobically. I committed to trying it for six weeks, the growth period for mitochondria.
It only took a week before I started to see results.
Keeping my heart rate below 139, my pace in my first “Maffetone run” was above ten-minute miles. A week later, it was a few seconds faster. Another week, and a few more seconds. Six weeks in, and I had taken an entire minute off my pace when running at my Maffetone heart rate (I test it once a week on the local high school track).
Maffetone uses a formula of 180 minus age to determine these target rates; starting with 180 isn’t supposed to approximate maximum heart rate (there’s another whole post coming about my obsession with that), but simply to be a way to guarantee that people end up under the right zone. There are some small adjustments to be made for running and injury history, but I left them alone. They might have meant me bumping down a few more beats, and I just couldn’t go that far.
All of which brings me to my birthday.
I’m not 41 anymore. I’m 42. My number should be 138 now, not 139. But I can’t do it. I can’t change that setting on my Garmin.
It feels a little bit ridiculous. It’s just one heart beat. And as far as I can tell, I should be enthusiastic about lowering that number. After all, it’s part of what has kept me healthy and clocking thirty-five mile weeks.
But I can’t bring myself to do it. That’s no birthday present.
I was thinking as I ran last Sunday that our kids love to celebrate their half-birthdays. Maybe I’ll change it when I’m forty-two-and-a-half.