satchboogie said:
actually, sometimes even if i'm extremely exhausted and force my ass to the gym, i have explosive workouts.
There is a reason for this.
Many times fatigue is associated with depression and various related factors such as serotonin and norepinephrine.
CATECHOLAMINES
The catecholamine molecules are epinephrine (adrenaline) and norepinephrine (noradrenaline).
During times of stress such as anaerobic and aerobic exercise, we activate our sympathetic nervous system. Norepinephrine is a neurotransmitter within the sympathetic nervous system. By stimulating nervous transmission, more norepinephrine is able to innervate the adrenal medulla, which is a component making up part of the sympathetic system. Increased innervation of this endocrine gland causes increased release of norepinephrine and epinephrine. When these two chemicals are released into the bloodstream they have an effect on distant tissues and so act as hormones.
The effects of the catecholamines on the nervous system are evidently more to do with norepinephrine as a neurotransmitter. Concentrations of serotonin, another neurotransmitter, are also affected.
Research studies into depression have shown that it is caused by low concentrations or impaired transmission of the neurotransmitters, noreinephrine and serotonin. By increasing the concentration of these transmitters when we exercise, their concentrations in the neurons will increase. Depressed subjects will improve and others will feel a lift in their mood.
BETA ENDORPHINS
Beta endorphins consist of 30 amino acid subunits and it is the beta endorphins which show the greatest increase in plasma concentration during times of exercise.
Endorphins are thought to be released from the pituitary during times of pain or stress. Studies have also looked into the affect of acidosis, caused by exercise, on endorphin release. Exercise induced acidosis of the blood appears when prolonged exercise has occurred and oxygen flow to the muscles has decreased. Anaerobic respiration occurs causing lactic acid accumulation, which results in acidosis. This acidosis is then thought to stimulate the pituitary to release the endorphins.
By having this analgaesic effect on the body, endorphin release results in a state of euphoria. As well as reducing pain this also aids in the reduction of stress. Due to these effects, endorphins are known as the body's "natural painkillers". Because they have similar actions to opiate drugs they are also known as the endogenous opioids.
Blood levels of beta-endorphins have been found to increase to as much as five times their resting levels during a prolonged bout of exercise. This measurement varies from person to person and is affected by how much regular exercise you take part in.
As tolerance of the body to opioid drugs increases with increased use over time, the pattern of tolerance to endorphins follows a similar path. The more regularly you exercise, the higher the body's natural tolerance to endorphins. This means that as you exercise more, you require a higher intensity of exercise in order to produce the same endorphin release. As with opioid drugs, exercise can become addictive, as athletes begin to require the analgaesic effects of the endorphins. This analgaesic effect is sometimes referred to as "the runners high". Like any addiction, exercise addiction can result in dependence, tolerance, and continued use or participation despite adverse affects, leading to the sacrifice other activities to devote more time to exercise.
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