Physical fatigue is defined as a decrease in muscle capacity after prolonged exercise. It is mainly related to the depletion of energy reserves and the accumulation of metabolites (such as lactic acid) that limit muscle contraction. (1)

• Intense physical activity : Sports, manual labor, or any activity that places heavy strain on the muscles.
• Lack of recovery : Insufficient rest prevents the regeneration of muscle fibers.
• Nutritional deficiencies : A deficiency in protein, iron, magnesium or vitamins can accentuate muscle fatigue.

• Feeling of muscular heaviness

• Reduced strength and endurance

• Muscle aches and pains

• Longer recovery time after exercise

Mental fatigue is a state of cognitive exhaustion that affects concentration, motivation, and decision-making. It is caused by excessive use of the brain, often linked to stress or excessive mental workload. (2)

• Excessive workload : Long hours of concentration on complex tasks.
• Chronic stress : Increases cortisol production, which reduces cognitive ability.
• Lack of sleep : Impairs cognitive functions and memory.
• Prolonged exposure to screens : Excessively uses the brain and reduces attention span.

• Difficulty concentrating

• Decreased motivation and feeling of weariness

• Irritability and mood disturbances

• Headaches and nervous tension