It’s a common myth that muscle soreness you feel after exercise is caused by lactic acid trapped in your cells. Studies have found that’s not true. Understanding lactic acid vs. metabolic acidosis can help explain what is actually happening in your muscles during intense exercise.
What is lactic acid?
Your body usually fuels your muscles with oxygen. If you start doing intense physical activity faster than your body can get oxygen to your muscles and other tissues, your cells break down glucose to create the energy you need to keep moving. Lactic acid is a byproduct of this anaerobic glycolysis.
However, the temporary rise in lactic acid isn’t dangerous and usually won’t cause any symptoms. Your liver and kidneys filter lactic acid out of your blood and break it down into glucose (blood sugar) that can be used for energy in the future. This is called gluconeogenesis. Lactic acid also attracts cells in your immune system to heal wounds and fight infections.
Some studies question the production of lactic acid in the body at all. Lindinger et al. determined that lactic acid may not be produced in meaningful concentrations, while Hall et al. went so far as to say that lactic acid might not be produced in the body, period. Other people simply consider lactic acid and lactate to be synonymous.
What is Metabolic Acidosis?
So, what do athletes experience with prolonged anaerobic exercise? They experience what’s called “metabolic acidosis”. When we use our muscles, the body breaks down ATP within the cells to cause the muscles to contract. This is called ATP hydrolysis. Every time this occurs, you have a hydrogen ion that gets released. The increase in hydrogen ions then decreases the body’s pH. If you decrease the body’s pH, you drive the body to be more acidic. If the body becomes more acidic, you start inhibiting glycolytic reactions, you start interfering with excitation-contraction coupling, and interfering with muscle cross-bridges. Basically, you start shutting down.
Basically, it becomes harder for your muscles to maintain the same level of performance. This temporary exercise-related response is different from clinical metabolic acidosis, which is associated with certain medical conditions.
What is the Lactate Threshold?
So it’s not simply a lactic acid or lactate buildup. The changes happening during intense exercise also involve increasing acidity. As the amount of effort increases, concentrations of lactate in the blood increase. When you get to a certain point, there’s an abrupt rise in lactate levels. That’s what is known as the lactate threshold.
This corresponds with the increase in hydrogen ions. So this means that you’re increasingly reliant on anaerobic energy production to produce energy for that activity. And at some point, if that exercise activity and intensity continue at that rate, you’ll have accumulated more hydrogen ions than your body can effectively buffer, and your body becomes more acidic.
That starts to put you in metabolic acidosis, and fatigue can increase, making it progressively harder to maintain the same exercise intensity.
The Takeaway Message
Metabolic acidosis is dependent upon two things: time and intensity. If you don’t properly train by either increasing the time or intensity of exercise too quickly, you run the risk of hitting the lactate threshold and throwing your body into metabolic acidosis.
LYT can help you build the strength, mobility, balance, coordination, and body awareness needed to gradually increase the demands you place on your body. By training progressively and learning how to move with greater efficiency, you can better prepare your body to handle increases in both time and intensity, helping you build capacity without asking your body to do too much, too soon.
The LYT Method focuses on building these qualities through intentional, functional movement.
