Muscle Fatigue

Muscle fatigue can be experienced by all kinds of active people of all different levels of fitness. Whether it’s weight training, long distance endurance training, or a low impact cardiovascular workout, muscle fatigue can be an unwelcome and uncomfortable occurrence. But what causes muscle fatigue and how can we prevent it?

First of all we need to look at how muscles work.

In order for muscles to work, they need to have a source of energy. Muscles use a substance called ATP (adenosine triphosphate) as their fuel, which they receive in two ways.

The first way is via aerobic metabolism using oxygen which is carried by the bloodstream (during low intensity exercise). This method provides a slow yet constant and plentiful supply of ATP during low intensity workouts, but it is insufficient in high intensity situations due to a limit on the amount of blood which can be circulated to muscles at any given time.

The second method of ATP delivery is via anaerobic metabolism (during high intensity exercise), which works faster and doesn’t require oxygen, however this process is also limited in the amount of ATP which can be supplied due to lack of stores. High intensity (anaerobic) exercise such as heavy weights or sprinting can result in faster muscle fatigue due to this limited supply of ATP.

The bottom line is... if your body is not producing or delivering ATP effectively, muscle fatigue is highly likely during training.

Your body needs a range of vitamins and minerals in order to produce ATP, including B vitamins, vitamin C, folate and magnesium. Aerobic delivery of ATP also requires a healthy amount of red blood cells, which relies on good levels of iron, vitamin B12 and folic acid in the body.

The role of the nervous system in muscle fatigue.

Muscles contract and relax in response to stimulation from the brain which is carried to the muscles via the nerves. The nervous system is therefore responsible for the regulation of the force of contraction of muscles. Some muscle fatigue may be caused by a nervous system origin, because if the nerves are not communicating their messages correctly, the muscles cannot contract and relax properly.

There are many nutrients needed for a healthy nervous system such as B vitamins, but the key ingredient here is magnesium. Magnesium is a hugely important nutrient for healthy function of the nervous system due to its regulatory effect on nerve conduction. Magnesium is also needed by muscles in order for them to relax. A lack of available magnesium in the body may cause problems such as cramps, spasm, tension and muscle fatigue.

Muscles need calcium to contract properly, and if the body is low in calcium, it may contribute to muscle fatigue. It is thought that after continuous use, muscles start to leak calcium via small channels, which can lead to muscle fatigue and weakness. There is an increased need for this mineral by active people, especially endurance athletes.

A few simple supplements may provide your body with the ingredients it needs to make energy for muscles, resulting in improvements on endurance and performance. For more information on vitamins and minerals for muscles, click here.