In the realm of sports and exercise, lactic acid has become the embodiment of evil. It's blamed for all sorts of ills: fatigue, soreness, burning sensations, etc. However, most of what you’ve heard about lactic acid isn’t true. Forget everything you know about lactic acid and let me set the record straight as your Physician Mythbuster.

When you're working out hard and doing your best to try to lose those last 10 pounds, it seems like every day your body gets more sore, making it harder and harder for you to keep up the “burn.” You're likely blaming your lactic acid levels. However, that's a hugely popular myth that during intense exercise your body produces lactic acid.

Your body's actually producing lactate during exercise, which is not an acid. Lactate is a product of the body’s process of breaking down sugar for energy. As you exercise, your body burns both fat and sugar. When your body burns sugar, it creates lactate. As you increase the intensity of your exercise, your body starts to burn more sugar and less fat. At some point, your body’s reliance on sugar dramatically increases.

The lactate in your blood also exponentially increases. This is known as your lactate threshold. In fact, lactate helps reduce the production of acid during exercise! Lactate is actually a buffer for acid production. So what exactly causes that burn during exercise? Stay tuned for my next blog as I blow the myth out of the water that lactic acid causes the “burn” you feel during exercise.

Now you know that your body isn't producing lactic acid during intense exercise, but actually the buffer lactate that reduces the production of acid. Since lactate is what is produced during exercise, lactic acid cannot be causing the “burn” you feel during exercise. Lactate isn’t responsible for the “burn.” Lactate is actually used by your heart, liver, and inactive muscle as a fuel source (this is a good thing).

So what causes the "burn"?

The biochemistry is complicated, but I’ll give you a simple summary. The chemical processes that produce energy during exercise create hydrogen ions. During low-intensity exercise, your body's able to process these hydrogen ions so that they don’t build up. However, during high-intensity exercise, the hydrogen ions get created so quickly that the body can’t buffer them. The hydrogen ions build up in the muscle, creating an acidic state. The hydrogen ions stimulate pain-producing nerves, and you feel a “burn.”

Basically acidic conditions produce the “burn,” not lactate or lactic acid. Hydrogen ions are produced so quickly that they cannot be buffered, or neutralized, and these hydrogen ions stimulate pain-producing nerves.

So during your last 10-pound boot camp regime, stop blaming lactic acid. It's all your hydrogen ions building up with no way to quickly clear. Stay tuned as I close the Mythbuster series with the last chapter of the lactic acid saga, to be posted Thursday.