Lactic Acid and Discomfort from Stiffness

Stiffness is an almost inevitable evil after physical exercise. To reduce aches and pains, we need to know why this occurs and how we can mitigate lactic acid production during and after sports.
Lactic Acid and Discomfort from Stiffness

Last update: 13 May, 2019

It’s common to blame lactic acid when our muscles are tired or when we suffer discomfort from muscle stiffness. The compound occurs mainly when we make extra effort during exercise. Find out more about this below.

What is lactic acid and how do we produce it?

Exercise and the effort made by our muscles, produces lactic acid through the chemical processes of pyruvic acid. Lactic acid is also produced through an enzyme called lactate dehydrogenase. Beyond scientific explanations, the truth is that after exercise, lactic acid increases. And it can cause pain and discomfort.

This doesn’t mean that non-athletes are lacking in this compound, rather their concentration is lower. Under normal conditions, there is less than 2 mmol/l of lactate in the blood. However, after exercising, this number can increase up to 12 mmol/l.

Lactic acid in sports

If you have been exercising for some time, you have probably heard or read about lactic acid? It’s very important to understand why it increases as we exercise.

We shouldn’t consider lactic acid as ‘the bad guy,’ as we may have been led to believe. The process of lactase increase in blood is actually beneficial, since it allows for the repair of damaged muscle fibers during exercise. Also, it ensures the production of energy. Otherwise, not only would our legs hurt more, but also we wouldn’t have the strength to get home after exercising.

Lactic acid effect. Woman after running.

Lactic acid comes from the decomposition of glucose during an anaerobic routine. For instance, lifting weights. The process begins after a short, but intense workout.

When we enjoy intense exercise, lactic acid accumulates faster than the body can eliminate it. The consequence? A build up of lactic acid in our bloodstream, which cause soreness in our muscle fibers. Without lactic acid, we would not be able to gain the energy and movement that we need. But, we have to overcome the barrier between calcium and muscle fibers (which allow for contraction).

Therefore, when we make too much lactic acid, we lack energy or fuel needed to contract the muscles. The only way to reduce the discomfort is to stop training until our levels return to normal.

But also, we must bear in mind that to avoid the consequences of excess lactic acid, the best remedy is training. It may seem contradictory, but it’s necessary to give the body a chance to create an adaptation mechanism.

To clarify, if we give our muscles more lactic acid, they will have a plan of action to evacuate it and support daily efforts. At first, it will hurt, it will be bothersome and it may even be uncomfortable to walk. But as time passes, we notice less fatigue in our extremities or muscle groups. From here we can start to increase our loads without any problems.

Lactic acid and muscle stiffness: demolishing myths

Lactic acid and shoelaces. Man running.

For a long time, it was thought that the increase of lactic acid in the bloodstream was the main cause of acidosis in the body. And, therefore, of the so-called ‘stiffness’ or ‘cramps’ derived from overexertion and fibrillar micro-burns.

However, investigations have removed that myth. Lactic acid doesn’t have the capacity to provoke cramps, since stiffness also occurs in people who don’t exercise and who also spend hours in the same position.

When acidosis develops during intense exercise periods, the body’s reaction is completely different and separate from that in which lactate intervenes.

Finally, a tip from those who practice running: after a race or training where the body is brought to its maximum capacity, the best way to prevent lactic acid from wreaking havoc is to perform a slow and smooth jog for a few minutes. This way the blood will be able to drain the excesses of lactate in the body.


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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.