Hydration plays a crucial role when engaging in physical activity, affecting both health and performance.

Proper fluid balance supports essential body functions like temperature regulation, cardiovascular efficiency, and muscle function.

Regulating Body Temperature

One of the primary functions of adequate hydration during exercise is maintaining optimal body temperature. Physical activity increases metabolic heat production, prompting the body to release sweat as a cooling mechanism. Sweat evaporation from the skin surface dissipates heat, preventing overheating. However, sweating results in significant fluid loss from the body’s reservoirs. Failure to replenish these fluids impairs the body’s ability to sweat effectively, leading to a rise in core temperature and heat stress, which can diminish physical performance and cause heat exhaustion.

Hydration mitigates this by restoring lost fluids, thus maintaining the body’s cooling efficiency. This effect is critical in hot or humid environments where thermoregulation challenges increase.

Enhancing Cardiovascular and Muscular Function

Water constitutes a large percentage of blood volume, directly influencing cardiovascular efficiency. Adequate hydration supports proper circulation, enabling oxygen and nutrient delivery to working muscles, which are vital for sustained performance. Dehydration reduces blood volume, forcing the heart to work harder to pump the diminished supply, which can result in increased heart rate and perceived effort.

Hydration also affects muscle function by preserving electrolyte balance and preventing cramps or spasms. During prolonged exercise, electrolyte loss through sweat if unaddressed, disrupts muscle contractions and cellular function. Drinking fluids that contain electrolytes during intense or extended workouts supports muscle endurance and reduces fatigue.

Supporting Recovery and Reducing Injury Risk

Fluid replacement post-exercise accelerates recovery by facilitating the transport of nutrients essential for muscle repair and metabolic waste removal. Proper hydration helps maintain joint lubrication through synovial fluid production, decreasing friction and potential injury during exercise. Replenishing fluids also aids in maintaining mental focus and coordination, further reducing injury risk related to fatigue or impaired neuromuscular function.

Recommended Hydration Practices

Experts advise consuming fluids before, during, and after exercise to sustain hydration levels. Drinking a moderate amount (~200 mL) around 30 minutes before starting helps ensure adequate hydration status. During exercise, intake should match sweat loss, approximately a glass of water every 15 to 20 minutes depending on intensity, duration, and environmental conditions.

For prolonged or high-intensity activities, beverages containing electrolytes may be beneficial to replace lost salts. Overhydration should be avoided to prevent hyponatremia, a rare but potentially severe condition caused by diluted blood sodium levels.

In a 2021 review titled Rehydration during Endurance Exercise: Challenges, Research, Options, Methods, Armstrong explains that during prolonged endurance activity there are two main hydration risks: dehydration — where water and sodium lost through sweat is not fully replaced — and overhydration — where excessive intake of diluted fluids leads to retention of too much water.

Hydration during exercise is vital for regulating body temperature, supporting cardiovascular and muscular performance, reducing fatigue, and promoting recovery. Attention to fluid intake before, during, and after physical activity safeguards health and maximizes exercise benefits. Following evidence-based hydration practices helps maintain optimal performance and minimizes health risks related to dehydration or excessive fluid intake.