Cool science info for the day…

Question for the day: Why do you breathe harder when you exercise?

If you’re like me, you probably think it’s because your body needs more oxygen. And that’s no doubt part of the truth, but there’s another piece of the puzzle that I didn’t know until today: you breathe more rapidly in order to keep your blood from becoming too acidic.

Here’s how it works (in Cheryl’s condensed and oversimplified science version):

When your muscles work, they metabolize energy-storage compounds to release energy and—in the process—they release acidic products like lactic acid.

Lactic acid moves into the blood stream where, if nobody does anything about it, it will make the blood acidic. Too acidic = bad.

Luckily, your blood contains a buffering system made up of carbonic acid (H₂CO₃) and the hydrogen carbonate ion (HCO₃^-)

In your bloodstream, there’s a constant back and forth reaction between these two guys. H₂CO₃ loses a proton (H⁺) to form HCO₃^-; HCO₃^- picks it back up again to form H₂CO₃.

When lactic acid comes on the scene, it adds more protons to the mix, which get picked up by HCO₃^-; the tricky part is that these compounds are a sort of teeter-totter. If there are too many on one side of the teeter-totter (equation), then they’ll slide back over to the other side. Interpretation: add more protons and it forms H₂CO₃, but if too much H₂CO₃ builds up, it will break apart again.

The solution is that the body has to get rid of the H₂CO₃. Which it does by means of another reaction that converts H₂CO₃ to water and carbon dioxide (CO₂.) This reaction is on a teeter-totter, too, though. They body has to get rid of that extra CO₂ or the whole process backs up like a tube slide full of kids.

How do you get rid of CO₂? You breathe.

So when you breathe harder when exercising, just think: you’re not just gaining oxygen. You’re lowering your blood pH!

(And when you think that, you may count yourself a true science geek :).)

Cheryl