What is lactic acid and how can it impact performance?
What is lactic Acid?
Lactic Acid, or lactate, is a normal by-product that our bodies produce during energy breakdown when oxygen is lacking.
Our bodies need energy to function and perform. Energy is provided to working muscles and body systems through the process of glycolysis. Glycolysis is the breakdown of glucose into a form that is usable as energy for our skeletal muscles. The preferable way for this to occur is with the use of oxygen. When oxygen is plentiful, this process is therefore what we would call aerobic, meaning with oxygen.
In normal daily activities such as walking, our muscles are working at a low intensity and therefore our demand for energy and oxygen is low. We are able to sustain a perfect balance of providing energy to our muscles with an adequate amount of oxygen. In this circumstance, lactate is not produced as the demand and supply are virtually equal.
When we start to exercise more vigorously our demand for energy and oxygen increases as our muscles begin to work harder. This is usually associated with heavier breathing as we attempt to transfer oxygen from our lungs to our muscles much quicker. Eventually, the demand for energy breakdown will exceed the available oxygen and glycolysis will become anaerobic, meaning without oxygen. It is only when glycolysis becomes anaerobic that lactic acid will start to be produced. The working cells can only sustain an anaerobic state for a short period of time, thus we recognise it as a signal to rest.
High levels of lactate increase the acidity of muscle cells. When cells are more acidic, the process of energy break down becomes less efficient. Our muscles are no longer able to sustain high levels of exertion within the acidic environment. Although it has the potential to inhibit performance, it is a natural protective mechanism to prevent serious muscle damage during extreme exertion.
What are the signs and symptoms of lactic acid build up?
A build-up of lactic acid presents as a burning sensation that we feel when are getting close to a state of fatigue. It may be accompanied by a visual shake of the muscle and a short-term feeling of loss of strength or power. It is a temporary sensation only and we recover quickly as the body clears the lactate and other metabolites when oxygen becomes plentiful.
Signs and associated symptoms:
Burning sensation in muscles
Shortness of breath
Historically, a build-up of lactic acid was said to be the reason for post exercise muscle soreness. It was thought that the more acidic environment in our muscles was the cause of several days of ‘heavy legs’ or delayed onset muscles soreness (DOMS) after strenuous exercise. We now know that is not the case.
It is more likely that muscle soreness after exercise is the result of tiny micro tears and cellular damage within the muscle fibres that occur during exercise. This process is completely normal and necessary for our muscles to get bigger and stronger. It is common for symptoms of DOMS to last between 24 and 72 hours.
How can I reduce the likelihood of lactic acid build up?
With any new exercise regime, you should build up slowly. In increasing our tolerance to exercise our bodies becomes more efficient in the processes necessary for oxygen delivery, energy breakdown, and energy utilisation. Eventually, your body will be able to tolerate more strenuous exercise with less discomfort by raising your lactate threshold.
Other strategies or considerations:
Eat well to ensure you are getting adequate nutrition for cellular processes
Get plenty of magnesium in your diet
Warm up before strenuous exercise
Allow for rest periods in your workouts
Have a balance or aerobic and anaerobic workouts across your week, e.g walking or low intensity workouts vs jumping, sprinting or HIIT
Do I need to be concerned about lactate build up?
No. The build-up of lactic acid can be a nice reminder to rest during workouts but it is not dangerous in small amounts. It is a normal process occurring within our bodies that we needn’t be fearful of. It is not something that people seek treatment for and is usually self-managed. Education is key. A good understanding of what lactic acid is and some consideration with workout planning is usually all you need for safe workouts.
Muscles of course do require recovery after strenuous exertion. Although this is not directly linked to lactic acid, it is recommended that individuals seek advice around appropriate loading if they are not recovering well or are suspicious of a short tissue injury.