Hydration guidelines for athletic performances

Water is a significant component of the human body, accounting for around 60% of an average adult's total body weight. It is divided into intracellular and extracellular water, with intracellular water constituting 55-65% of the body's total water. The osmotic action of ions or electrolytes primarily determines the distribution of fluids between these compartments. The primary osmotic solvent in intracellular water is potassium (K+), while sodium and its conjugated anions, including chloride and bicarbonate, play a crucial role in regulating extracellular water volume and movement. The daily needs of athletes are determined by the total body water loss, with athletes having higher daily needs due to their higher water losses. Fatigue in sports is mainly caused by muscle exhaustion and dehydration. A proper hydration protocol, implemented before, during, and after competition, can enhance performance and recovery. Humans have developed adaptations to regulate body temperature, such as the ability to produce sweat through sweat glands. This allows the body to release heat into the environment and maintain a stable internal temperature. However, high humidity levels can increase the body's temperature, potentially threatening an athlete's health. The rate of transpiration, or sweat production, depends on various factors, including training duration, wind speed, ambient temperature, relative humidity, and exercise intensity. Dehydration is a dynamic process in which the body loses water, affecting both physical and mental functions. It is crucial to start physical activity with correct hydration, provide liquids during exercise, and reconstitute lost water after exercise. Determining the state of hydration involves assessing changes in body weight, urine color, and blood indices. Dehydration can be classified as isotonic, hypertonic, or hypotonic based on the loss of ions relative to body water. The most significant loss of liquid during exercise is due to urine, which is a hypotonic fluid. The acclimatization of athletes improves the kidneys' ability to absorb sodium. Homeostasis mechanisms aim to prevent excessive sodium loss, but if sodium concentration is below a minimal level, organic hypertension and even death may occur. Recommendations for good hydration during exercise include averaging 5-7 ml/kg of urine 4 hours before exercise, consuming 5-7 ml/kg 2 hours before exercise, and maintaining a liquid temperature below ambient temperature. For more extended exercises, sports drinks should be consumed at regular intervals to avoid a loss of more than 2% of body weight. Sports drinks are classified based on their tonicity or osmolarity relative to blood plasma.