The last myth to dispel is that lactic acid is the root cause of all muscle soreness, and ultimately, fatigue. Again, I have to be brutally honest here and let you know this is FALSE!

Lactate isn’t responsible for the soreness you feel a day or two after exercise. It’s impossible for lactate to cause this. Lactate is cleared from muscle within minutes after you’re done exercising. The true cause of muscle soreness is muscle damage.

When you do exercise that your body is not used to, you create small microtears in the fibers of your muscle. Over the next 8 hours or so, white blood cells infiltrate into the damaged tissue to help clean up metabolic byproducts of this damage. They release chemicals that stimulate pain receptors in the muscle. Therefore, you wake up the next day with sore muscles.

In terms of fatigue, as I mentioned before, lactate is used by your body as a fuel source. Since it helps reduce acid production, lactate is a good thing! In fact, research has shown that lactate has beneficial effects on the performance of muscle fatigue in rats.

The hydrogen ions (the acid produced during exercise) also don’t contribute to fatigue. Research on single muscle fibers has shown that when their environment becomes acidic, they don’t fatigue any faster than normal.

The real causes of fatigue during exercise aren’t well understood. However, recent evidence indicates that the accumulation of potassium in the muscles may contribute to fatigue. In fact, when you increase the amount of potassium in an isolated muscle fiber, the amount of force that it can produce goes down.

The bottom line is that lactic acid is a phantom menace. The body doesn’t even make lactic acid. Lactate is actually our friend and plays important roles during exercise. So, the next time you “feel the burn,” don’t blame the lactic acid. Tell your workout partner, “Wow, those hydrogen ions are really killing me today!” At least it might just intimidate enough to help you win the game.