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Hydration is a fundamental aspect for active individuals, especially for those who engage in regular workouts. Maintaining an adequate state of hydration is key for physical performance, overall health, and injury prevention. Even mild dehydration can negatively affect physical performance and cognition, impacting decision-making, concentration, and coordination.
60% of an adult’s weight is water:
- Muscle: 75% water.
- Bones: 25% water.
- Adipose tissue: 5% water.
The human body is largely composed of water, which plays a crucial role in numerous biological functions. In fact, about 60% of the total weight of an average adult is water. This proportion varies considerably among the different tissues and organs of the body, reflecting the importance of water in various structures and body functions.
Muscles, which are fundamental for movement and structural support, contain approximately 75% water. This high proportion of water in muscle tissue contributes to its functionality, as water facilitates the chemical reactions that occur during muscle contraction and aids in the transport of nutrients and the removal of waste.
Bones, often considered rigid and dry structures, contain about 25% water. Although in a lesser proportion than in muscles, this amount of water is crucial for bone health. Water in bones participates in metabolic processes, helps maintain their strength, and is essential for the production of bone cells.
Adipose tissue or body fat has a significantly lower water content, about 5%. Although it contains less water compared to other tissues, adipose tissue plays an important role in energy storage, insulation, and the protection of vital organs.
Regulates body temperature: During exercise, the body generates heat. Sweating and its evaporation are key mechanisms for cooling the body. Without sufficient hydration, this mechanism can be less effective, increasing the risk of overheating and heat stroke.
Muscle and joint function: Muscles and joints need to be well-hydrated to function properly. Dehydration can lead to a decrease in muscle strength, increased fatigue, and an elevated risk of cramps.
Nutrient transport and waste removal: Water facilitates the transport of nutrients to cells and assists in the removal of metabolic wastes. Adequate hydration is essential for these processes.
Recovery: Rehydration is a key component in recovery, helping to replenish lost fluids and facilitate muscle repair processes.
Recommendations for proper hydration
Pre-workout: Start training in a well-hydrated state. It’s advisable to drink water regularly throughout the day and consume a glass of water before beginning exercise.
During training: The amount and frequency of hydration will depend on the duration and intensity of the exercise, as well as environmental conditions, especially in hot conditions, it’s important to replenish not only water but also lost electrolytes (such as sodium and potassium). This can be done through sports drinks, electrolyte-rich foods, or supplements. In general, it’s advisable to drink small amounts of fluids regularly during training.
Post-training: It’s important to replenish lost fluids. A good rule of thumb is to drink about 1.5 times the volume of body weight lost during exercise. It’s recommended to consume at least 150% of the weight loss in the first 6 hours after exercise, to cover the fluid eliminated both by sweat and urine and thereby recover the water balance. Therefore, considering that 1 liter of sweat equates to a loss of 1 kg of body weight, you should drink 1.5 liters of fluid per kg of body weight lost.
If a 60 kg person loses 1 kg of weight (equivalent to approximately 1 liter of water) during exercise, they should aim to replenish approximately 1.5 liters (1500 ml) of fluids after exercise to compensate for the loss of fluids and facilitate adequate recovery. This table can serve as a general guide for rehydration after exercise.
| Weight (kg) | Water (liters) |
|---|---|
| 60 | 0.90 |
| 65 | 0.98 |
| 70 | 1.05 |
| 75 | 1.12 |
| 80 | 1.20 |
| 85 | 1.28 |
| 90 | 1.35 |
How can I know my hydration status?
The color of urine can be a useful indicator. Light-colored urine indicates good hydration, while dark urine suggests dehydration. Another aspect to consider is sweating during training, which is a physiological process necessary for body temperature regulation, but also involves significant loss of fluids and electrolytes (especially sodium), affecting hydration needs. The rate of sweating varies significantly among individuals due to various factors, and understanding these variations is essential for developing effective and personalized hydration strategies.
Beverages like alcohol and excessive amounts of caffeine can increase dehydration.
Alcohol ☠️
Alcohol is a diuretic, which means it increases urine production and can lead to a loss of fluids and electrolytes. It’s important to be aware of the associated risks, as alcohol, from a medical and nutritional perspective, is considered a toxin to the human body. And its consumption, especially in physically active individuals and after training, inhibits muscle protein synthesis, negatively affecting repair and muscle growth.
Caffeine 🤎
Caffeine is widely used in the sports world for its stimulant and performance-enhancing effects, it can help improve endurance and reduce the perception of effort. Also, it can increase the mobilization of fatty acids, allowing the body to use fat as an energy source more effectively, and even acts as a stimulant of the central nervous system, helping to delay the onset of fatigue. However, its consumption should be moderate, especially in relation to hydration, as it has diuretic properties, stimulating the kidneys, which means it can increase urine production. This could contribute to dehydration that negatively affects physical and mental performance, increase the risk of overheating, and cause muscle fatigue. Therefore, it’s advisable to ensure good hydration, especially if consuming caffeine before or during exercise. While it’s a useful tool for improving sports performance, it’s essential to use it responsibly and consciously, paying attention to hydration.
Consequences of dehydration
The loss of body water, even in small amounts, can have significant effects on physical performance and cognitive functions, and severe dehydration can lead to serious health consequences.
Different levels of water loss impact the body:
| Loss | Effects |
|---|---|
| 3% | Decrease in physical performance, increased fatigue, thermoregulation problems. |
| 5% | Impairment of cognitive functions, headache, irritability. |
| 10% | Life-threatening risk, organ dysfunction, circulatory failure, risk of heat stroke. |
3% Body Water Loss
Even mild dehydration, such as the loss of 3% of body water, can lead to a noticeable reduction in physical performance. This can manifest as increased fatigue, reduced endurance, decreased muscle strength, and an increase in the perception of effort. The body’s ability to regulate its temperature may be affected, increasing the risk of overheating, especially in warm environments or during intense exercise.
5% Body Water Loss
Losing 5% of body water can begin to deteriorate cognitive functions, such as concentration, attention, and short-term memory. This can affect decision-making, motor coordination, and reaction capacity. Symptoms such as headache, irritability, and an increase in heart rate may appear.
10% Body Water Loss
Dehydration reaching 10% of body water is extremely serious and can be life-threatening. It requires immediate medical attention. Symptoms include organ dysfunction, circulatory failure, risk of heat stroke, and in extreme cases, can lead to collapse and loss of consciousness.
SODIUM, avoiding overhydration
Electrolytes such as sodium, potassium, and chloride, are essential for maintaining neuromuscular function and fluid balance. Sodium is an essential electrolyte that plays a key role in regulating the body’s fluid balance and is essential for neuromuscular function and blood pressure regulation. Providing sodium during hydration is especially important in certain situations related to physical exercise and environmental conditions, especially heat.
Care must be taken with hyponatremia, which can cause cerebral edema, alterations in the level of consciousness, or even death. Hyponatremia is a medical condition characterized by an abnormally low concentration of sodium in the blood. Its symptoms include nausea and vomiting, headache, confusion or altered mental state, or loss of energy and fatigue.
The amount of sodium lost through sweat ranges from 0.5 to 2.5 liters per hour, depending on the individual. Its use is only recommended for very prolonged exercises, such as marathons or ultramarathons, or when replacing more than 80% of fluid losses.
