Hydration is a fundamental part of nutrition, as it must comply with the water losses of an organism composed of 50 to 75% of water;
Especially in sports, hydro-saline rehydration is an ESSENTIAL habit for optimizing performance and maintaining health. In sporting practice, in fact, the considerable water losses induced by sweating can determine the onset of IPOhydration, ie a reduction in body water in all the compartments, in particular in the circulatory stream; the relative complications determine a series of negative effects that significantly compromise some physiological systems and / or mechanisms:
- Limitation of heat dispersion capacity
- Reduction of tissue oxygenation
- Variation of electrolyte distribution
- Variation of intra and extracellular volumes
These effects are accompanied by some easily recognizable symptoms:
- Thirst
- Sense of unease and oppression
- Nausea
- Irritability, dizziness, weakness and mental confusion
The sportsman's hydration must be carried out before, during and after the performance; furthermore, it must meet various requirements useful for improving water absorption:
- The concentration (osmolarity) of the drink must be mildly IPOtonic
- It must contain the mineral salts most subject to dispersion, namely potassium and magnesium (sodium only in cases of extraordinary sweating)
- It must contain a small percentage (5-7%) of carbohydrates, indispensable elements (together with the minerals mentioned above) to the rapid and effective absorption of water and the optimization of energy reserves
- It must be at a temperature between 6 and 10 ° C.
In some cases (due to ignorance, neglect or due to reasons independent of the athlete) water losses increase dangerously. Let's see what risks are run ignoring the excessive sweating caused by intense and prolonged exercise.
| Loss% of Liquids | Effects |
| 2% | increased thirst, the sense of "oppression" appears and the appetite decreases. |
| 3% | increased blood concentration and decreased urination. |
| 4-5% | increased perception of effort; skin spots appear, drowsiness, apathy and nausea. Decrease concentration and emotional stability. |
| 6% | increase in heart rate and respiratory rate; impaired thermoregulation capacity. |
| 8% | appearance of dizziness, difficulty with work and speech, mental confusion; significant reduction in strength and subsequently in balance. |
| 10% | appearance of muscle spasms, cramps and delirium. |
| 11% | Marked haemoconcentration and reduction in blood volume; renal failure, cardiocirculatory failure, cardiovascular collapse and probable COMA. |
| > 11% | coma and probable DEATH |
Obviously, reaching a dehydration equal to or greater than 10% represents a behavior almost always forced by extreme weather conditions ... for example the "100km of the Sahara"; however, even in less demanding situations it is possible to reach highly limiting levels of IPOhydration. It is the case of long competitions ... perhaps associated with unintelligent food behaviors; some examples are:
- alcohol abuse (most often consumed in the evening meal of the previous day);
- massive integration of nervini (especially caffeine)
- the use of diuretics.
The situation may be aggravated by:
- the lack of thirst (typical of the elderly);
- the use of unsuitable clothing (typical of beginners, mistakenly convinced that wearing raincoats or slimming suits helps them lose weight);
- the use of certain drugs (diuretics, antihistamines, antihypertensives);
- particular physical conditions (dysentery, vomiting, diabetes, etc.).
