In some people, muscles do not eat properly and therefore do not work well. This usually does not appear at rest, but during exercise. That is, as long as a person does not jerk too much, then he does not notice problems. But during serious work, all sorts of oddities begin. Muscle pain may appear, cramps occur after work, and in general it is impossible to work for a long time.
What does muscle eat
Muscle usually feeds on glucose, glycogen, and fatty acids.
At rest, the muscle eats fatty acids.
During intense physical activity, when a person is pushing and breathing little, the muscle uses glucose. And without oxygen.
With moderate exercise, the muscle feeds on a soup of glucose and fatty acids that float in the blood. If the load increases, then the muscle switches from fatty acids to glucose and glycogen. The higher the load, the more the muscle begins to like glycogen.
Glycogen is the animal analog of starch. Canned glucose is tightly packed in it.
At some point, glucose and glycogen stores are depleted, and performance deteriorates sharply. Athletes call this a "marathon wall". That is, it is impossible to run further.
In general, the choice of fuel for muscles is highly dependent on the duration of the exercise.
If you jog on the sly, then during the first hour, the muscles will feed on glucose, glycogen and fatty acids.
For about four hours, the consumption of fatty acids will increase, and then the muscles will eat mostly fat.
Glycogen and glucose
Muscles can use glucose even without oxygen. This happens during heavy physical exertion, when, for example, you have to lift something heavy. The person is pushing and does not breathe. The blood flow to the muscles also practically stops. In this case, energy can be obtained from glucose, but at the same time a lot of lactic acid is obtained. It acidifies the muscles, and severe weakness sets in.
If we breathe freely while running or riding a bicycle, then glucose is burned in the oxygen that we inhaled, and just water and carbon dioxide are obtained. So you can run for a long time.
Fat
Muscles are very fond of eating fatty acids. They take them from blood or from adipose tissue. This occurs during prolonged, low-intensity physical activity (longer than 40-50 minutes).
When our bodies are fed on fat, there are many ketone bodies like acetone. This is also a good fuel. Especially for the brain.
