As I’ve been chronicling these past few weeks, I’m on a 12-week program to make myself run a half-marathon. I’ve been quite faithful to it, but have become frustrated about my speed. My goal has been to increase distance rather than speed, but I figured that regular training would just naturally bring at least a slight increase in pace. Not only has that not happened, but my pace has actually slowed, sometimes by 30 seconds per mile. Now, thanks to the Times, I know that I’m not a lazy weakling and can blame it on the season:

One reason performance declines on sultry, humid days is that working muscles have to compete with the skin for blood. Directing more blood to the skin removes body heat and helps keep your body’s temperature from rising to dangerous levels. But that can mean less blood reaches muscles. At the same time, when your body becomes hotter, muscle enzymes speed up, burning glycogen more rapidly, depleting stores of the sugar that the muscles use for fuel.

Whole article here. Basically, even real athletes are unable to maintain a decent pace (a relative term, of course) when it’s hot. So this, and the fact that blood pools in the lower extremities in hot weather, explains why my legs feel so heavy when I run, even when I’m not that fatigued. The depleted sugar also must explain why I’m eating such insane amounts of dried fruit lately. I guess the one good thing about this is that I’ll be in awesome shape come this fall (October), when I’ll enter a real half-marathon. For now, I’ll plug along as best I can and try not to feel too bad about my inferior pace.

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