We’ve all been in the middle of a workout and had our legs feel like they are on fire. It comes out of nowhere and leaves you barely able to continue your training session. It almost feels like you’re turning into the Tin Man. It gets harder and harder to move. You stop for a second and take a couple breaths and it gets better, only to return a few seconds after continuing your training.
This is all because of lactic acid. It’s a common byproduct your body produces all the time but during short intense exercise we produce a whole lot more of it.
Aerobic vs Anaerobic
Your body has several energy systems the keep it going. These systems turn off an on depending on the intensity and duration of the need. Two of these systems are your Aerobic and your Anaerobic systems.
Your aerobic system is fueled by oxygen. You breath oxygen into your lungs and some biology happens. Then you exhale carbon dioxide as a byproduct. The aerobic system is in use for less intense sustained efforts longer than about 10 minutes. The system is pretty efficient and can run at a high level for a pretty long period of time. Think of this like the engine in a hybrid car. Not a great 0-60 speed but can go and go and go.
Your anaerobic system fuels short intense efforts like heavy weightlifting or sprints. These efforts are usually over before the aerobic system would even have a chance to off the starting line. This is your high performance racing engine. Because of this the anaerobic system needs to run on different fuel. Your body uses Glucose or sugars stored in the body (muscles and liver) to fuel the anaerobic system and the byproduct from this process is lactate or lactic acid.
Remember how efficiently we get rid of the carbon dioxide in the aerobic system? We just breath it out. Unfortunately the lactic acid isn’t disposed of as efficiently. It builds up in the muscles and that’s what makes them burn during a hard training session.
When you stop for a couple seconds your body catches up on getting rid of it but not enough to not pile up again after a few seconds. This is why we often perform sprint intervals and give you some time in between for your body to clear out the lactic acid. The anaerobic system only works for about 3 minutes before you can’t sustain that level of intensity and you slow down and start working in another energy system.
What can I do about lactic acid?
While it’s not going anywhere as it’s part of how our bodies work there are some things you can do to be in a better position to deal with it.
Lactic acid is water soluble. This means it dissolves in water. If you’re properly hydrated your body will be much more efficient at getting that lactic acid out of your muscles.
Just because you may primarily be using your anaerobic system doesn’t mean your other systems are sleeping. Keep breathing so that the energy you do get from oxygen is at full capacity and giving you all the help it can.
Train the system
Just like our muscles our energy systems can be trained and improved. When we have heavy lifting or a short workout under 3 minutes programmed make sure you’re pushing yourself hard to increase your bodies ability to adapt to the lactic acid. Adaptation happens in more than just our muscles.
Pushing yourself hard will make each workout hurt and your potential for Delayed Onset Muscle Soreness (DOMS) will increase but over time you’ll be able to push harder without the lactic acid slowing you down quit as much.
Now go move better.