What happens in the body and in the brain when you are tired? Why is it that you feel tired after an effort? Why are you dejected and “low” after prolonged worry?
People take both these forms of tiredness so much for granted that they don’t bother to find out what is happening to them. But fatigue is a form of toxicity (poisoning).
First, take a look at muscular fatigue. The poisoning develops in three main phases.
1. EFFORT: This entails a large consumption of sugar and oxygen by the body.
Imagine you are going to ride a bicycle for an hour. Your leg muscles need to be fed with energy to keep you going.
This energizing food is the glucose manufactured in the body, or more exactly the glycogen – glucose transformed and stored by the liver, which releases it as required.
The more intense the muscular effort the more the muscles eat up the glycogen – which can only be effective with a certain amount of oxygen.
French physiologist Dr. Chaveau has demonstrated that a working muscle absorbs 20 times more oxygen than a muscle at rest. The oxygen supply is ensured both by lungs and circulation. It is the blood which conveys it to the muscle.
The oxygen-glycogen combination produces lactic acid, which is the contracting agent of the muscle. This lactic acid will then be transformed into the waste matter – carbonic acid and water – and carried away by the blood, to be eliminated.
2. CRAMP: This is the first stage in the poisoning of the muscle.
As long as the liver succeeds in supplying enough glycogen, the lungs in carrying enough oxygen, the heart in making the blood circulate quickly enough to carry waste products to the kidneys – and the kidneys in filtering the toxic acids – everything goes well.
But if the effort becomes too great the overstrained muscles load themselves with carbonic acid, lactic acid, and water. In other words, they become loaded with poisons. This overloading of toxic acids can provoke cramps, which are a warning sign of fatigue.
3. FATIGUE: A state of general toxicity.
If the effort continues, the acids which are forming in the muscles will continue to pour into the blood, where they will not be correctly eliminated.
The blood, following its course, will distribute them throughout the body.
Result: a general poisoning is produced which attacks not only the muscular system but all the organs, as well as the central nervous system.
The brain sends out the alarm: fatigue. Finally comes exhaustion.
Physiologists have demonstrated the existence of this poisoning by injecting the blood of an exhausted dog into the blood of a dog which has just woken up, fit as a fiddle, and bounding around. After the injection, the newly awakened dog also shows signs of exhaustion.
Fatigue changes the composition of the cells. In normal conditions, they contain potassium but not sodium. The latter, provided by the salt you eat with your daily meals, stays outside in the interstitial tissues.
When a person is tired, the sodium enters the cell and the potassium is rejected. Potassium and sodium are enemies and cannot stay together. The loss of potassium also produces tiredness and cramps.
The adrenal glands (near the kidneys) are a vital cog in the anti-fatigue machinery. Specialists call them the energy glands. The kidneys eliminate part of the lactic acid in urine. But the adrenal glands intervene before this, at the stage when the muscle is getting tired. They purify it.
In addition, the adrenal glands secrete adrenalin, which acts on the heart to activate the circulation of the blood. The brisker the circulation the more quickly the blood is purified.
When we are in a state of lowered resistance, these glands are the first to slow down. There is a reduction in the production of adrenal hormones as soon as you lose your fitness. On the other hand, an athlete’s “form” is good when his adrenals are working well.
How about intellectual and psychological fatigue? What happens when the brain is tired?
Scientific knowledge of this is less, but it seems that excessive cerebral efforts can also produce a form of poisoning which attacks the basic nervous system.
Neuro-physiologists believe that the state of fatigue corresponds to a certain nerve pattern in the brain which they call a pattern of neuronal activity. But, as yet, they hardly know anything about this pattern.
On the other hand, they have observed certain modifications in the outlines of encephalograms in cases of intellectual fatigue. An encephalogram gives a specialist a “picture” of the brain somewhat akin to that which a cardiograph gives of the heart.
What is psychological fatigue?
In effect, it means you can feel very tired simply because you are sad or have had an argument with your husband or boss.
What happens, in this case, is that a feeling, an emotion, a sadness reverberates through the intermediary of the brain on to the pituitary gland, which has close links with the hypothalamus, the lower center of the brain, the nerve center which regulates the secretions of the endocrine glands.
These glands act in their turn on the adrenal glands, slowing’ their activity. As seen above, this adrenal laziness provokes fatigue.
And what about the kind of fatigue which is caused by sickness? For this, you must see your doctor.