Dehydration and sport: what are its consequences?

Losing fluids through sweat is common during training. However, insufficient hydration can produce symptoms of varying severity.

Last update: 18 January, 2022

Hydration during physical activity has the main function replenish water and mineral salts that are filtered through sweat. It is common for dehydration and sport to be linked, due to the amount of fluids lost in training.

Factors such as the temperature of the environment and the intensity of the exercise influence when achieving a good water balance. In any case, water should be consumed under any condition in which sports are practiced.

Dehydration can cause everything from cramps to serious internal injuries. For this reason, it is essential to follow a series of tips to avoid reaching that state. As well as being clear about the symptoms and ways to treat it.

Why does a state of dehydration occur?

Two thirds of the human body is made up of water. This fluid represents between 50% and 70% of body weight, so its constant replacement is a primary need. When the amount is reduced below the required levels, the state of dehydration is possible.

Various factors contribute. Especially when it comes to dehydration and sports, since environmental conditions become decisive.

It is not the same to train with 15 degrees Celsius outside temperature than with 33. In addition, the level of humidity, exposure to the sun, the clothes worn and physical condition have an influence.

During a routine it is common to relegate or forget the feeling of thirst. Going too long without taking intervals to drink water exposes the body to excessive fluid loss, which leads to fatigue.

Stopping to drink water while playing sports is a good habit. Even if you don’t feel thirsty specifically.

Internal effects of dehydration

Water, together with electrolytes, is essential for the chemical effects of the organism that produce the conduction of the nervous stimulus. In addition to contributing to muscle contraction.

Lack of hydration has negative effects that are manifested in the following areas:

  • Temperature: Altered body temperature produces increased sweating.
  • Red blood cells: increases its concentration, which results in an increase in blood viscosity.
  • Muscle: blood flow to this tissue is reduced.
  • heart rate: increases.

Being overweight and lack of regular exercise have a negative influence. Especially if you intend to train with intensity after a long time stopped.



Consequences of dehydration in sport

Excessive fluid loss during sports activities reduces aerobic capacity. The symptoms that manifest vary and can range from cramps to internal organic problems and heat stroke.

Thirst is the first indicator of dehydration. Although it is not to set off alarms, you should pay attention to it and drink water.

Depending on the level of fluid lost, measured as a percentage of body weight, the following effects occur:

  • Between 2% and 3%: decreased physical performance. Feeling of fatigue and dry mouth.
  • Between 4% and 6%: cramps, dizziness and tiredness. Reduction of urine level. Increased heart rate and body temperature.
  • Between 7% and 10%: Such a high level of fluid loss can lead to contractures and headaches. Organs such as the liver and kidneys may be affected.
  • More than 10%: life-threatening and possibility of heat stroke.

Although dehydration is treated by drinking more water, there are cases in which a medical consultation is advisable. For example, when it happens in repeated situations or when feelings of dizziness and reduced urine are frequent. It must be ruled out that they are indicators of other diseases, such as diabetes.

Tips for maintaining optimal hydration during exercise

The loss of water and mineral salts is normal during physical activity. This is due to sweating and the impossibility of instant replacement. However, it is important to achieve a water balance that prevents the appearance of symptoms.

A guideline to follow is to hydrate well before exercising. This involves drinking between half and a liter of water during the two hours before training.

On the other hand, you must also drink water during the activity, at intervals of no more than 20 minutes. This time is reduced if the heat is excessive or there is excessive sweating. What’s more, hydration at the end of training is essential to replenish as much fluid as possible.

Finally, there are other aspects to take into account to avoid the link between dehydration and sport:

  • Intensity: If the routine has a high level of intensity, hydration should be increased.
  • Temperature: drink more water if the temperature or humidity of the environment is high during the activity.
  • Personal situation: having a daily consumption of water prevents dehydration.
  • Cold: the water consumed during training must be cold.
Isotonic drinks are reserved for high-performance athletes or high-intensity athletes. In all other cases, water is enough.

types of drinks

There are commercial soft drinks intended to replenish minerals after training. In general, the best option to stay hydrated is water. Isotonic drinks are more common in intense or competitive level practices, because they contain minerals.



Avoid dehydration in sport

It is important to be extra careful if you train during days of intense heat. Especially when practiced outdoors. Avoid the midday hours, being the first morning or the evening the most recommended times.

On the other hand, starting the activity gently and gradually increasing the intensity allows for progressive adaptation. You should always have a bottle of water nearby. Staying hydrated during training reduces the risk of injury and improves performance.

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