Heard a story on KCRW this morning. Apparently lactic acid might not be responsible for muscle fatigue after all (as my high school biology class taught). The connection was made because lactic acid was found in fatigued muscles, but recent research suggests that it may prevent muscle fatigue. It turns out that if lactic acid is removed from overworked muscle fibers, they actually stop working.
Of course, it is probably responsible for the burn you get while exerting.
(It’s kind of like when I learned that a fever was actually an immune system technique to fight infection, and not something the infection did itself.)
That makes perfect sense. It reminds me of. . . er, a neurochemical whose name I can’t remember. Auriel told me about it. I think it has to do with cortisol. Anyway, it builds up over the day, and gradually makes us feel more and more tired and sluggish. We absorb it in our sleep. We produce it at increased rates sometimes when we’re really sick, and that’s why we feel so inordinately tired then. It’s good for us because it discourages us from expending energy we can’t afford to use.
And caffeine makes us numb to its effects. That’s why coffee can make you feel wide awake. The biggest danger with caffeine is that when you’re on it, you’ll overextend yourself without noticing, and eventually wreak long term damage. Or you won’t notice you’re really sick until you’ve made a sickness much, much worse.