Fatigue and Exercise
Fatigue is a feeling of weariness, tiredness or lack of energy. It can be a normal and important response to physical exertion, emotional stress, boredom or lack of sleep. It is a normal consequence of exercise, either high intensity exercise or prolonged exercise.
Fatigue has been classified into 2 types: peripheral and central.
Peripheral fatigue
Peripheral fatigue has been described as fatigue due to altered muscle function. It is the result of:
- An inability for the body to supply sufficient energy to the contracting muscle to meet increased energy demand (glycogen depletion).
- Dehydration caused by loss in water and minerals necessary for muscle function: magnesium, calcium, potassium and sodium.
- An accumulation of lactic acid and other acidic anaerobic metabolic by-products in the muscle.
The signs of peripheral fatigue are: muscle and joint pain, stiffness, soreness, cramps or burning sensation of muscle.
The effects are usually short term, a few days; and recovery is helped by rest, re-hydration and proper nutrition.
Central Fatigue
Central fatigue is attributed to signals arising from the central nervous system, directing a decrease in performance via a change in the frequency of action potential in motor neurons. It may occur secondary to pain, dyspnea, perceptions of exertion, hypoglycemia, hypothermia, ammonia accumulation and altered amino acid metabolism. The central fatigue in response to those stimuli is highly variable lasting from a few days to few months and could lead to burnout.
Prevention of Fatigue
It is essential to avoid muscular fatigue to prevent any signs of over-training. The nutrition of the athlete is critical and rests on two basic principles: proper hydration during the effort and manipulation of energy supply (glycogen concentration in skeletal muscle and liver). This is achieved by proper carbohydrates intake before the effort, glucose supplementation during the exercise and allowing enough time for glycogen re-synthesis after exercise.
Complete recovery from muscular fatigue between training sessions and competition is critical to prevent central fatigue.
PRS-Sport -- A major help for recovery
The use of PRS-Sport has been associated with a clear increase of the activity of the autonomic nervous system. The accelerated glycogen re-synthesis induced by the autonomic nervous system enhanced activity prevents energy depletion and exhaustion. All athletes using PRS-Sport had a better ability to focus and a better recovery both physically and mentally.