At some point the words lactic acid or acidosis has been put forth in a firefighter class on cardiac arrest, fitness or maybe in a heat cramps lecture. You hear lactic acid and lactate used interchangeably by fire and EMS educators or those talking about acidosis as a reference to muscle breakdown.
The truth is that there is a difference between lactate and lactic acid.
Your body produces lactate in response to aerobic exercise; it serves as a fuel for the muscles, delays fatigue and prevents injury. Lactic acid contains one additional proton and is not produced during exercise, but from carbohydrate metabolism in the absence of oxygen. Lactate does not cause muscle burning. It is actually a fuel source that keeps the muscles going until they are fatigued. Lactate also does not cause acidosis in the muscle, but helps alleviate it by transporting the hydrogen ion out of the muscle making lactic acid into lactate.
During hard exercise and exertion from firefighting efforts, breathing increases to deliver more oxygen to the working muscles. Some aspects of firefighting are so intense that your body cannot use oxygen fast enough to create fuel.
For these quick, intense bursts of activity, your body needs to move into anaerobic metabolism. During anaerobic metabolism the stored energy in your body is broken down into a compound called pyruvate.