The hydration during a race is essential to compensate for the fluid we lose through sweat. While dehydration is negative so is drinking. How do we know what is the right amount?
If you are someone who regularly practiced running know is the importance of being well hydrated before, during and after training. The amount of liquid that we lose during a race depends on our physical, atmospheric features of the site, such as temperature and humidity, and the intensity and duration of exercise. Nevertheless, there are some general recommendations as to not drink more liquid than expel with sweating, that is, we must maintain a slight dehydration. Excess water can end in hyponatremia, swelling of the cells has too much liquid can cause vomiting and heart failure.
The point of balance in terms of hydration refers is called rehydration, a normal level of plasma electrolytes. Food intake and adequate fluids during the 12 hours before a race should be sufficient to face the training but if for any reason at that time have not received adequate hydration would be enough to drink between 5 and 7 ml of water every kilo of body weight. If the urine is dark in a color we increase the amount of water if it is too light means that we have an excess of liquid. Remember that foods like salty snacks increased the thirst and fluid retention.
More or less sweating also depend on the type of clothing we use, atmospheric factors, genetic features … Most experts recommend a simple advice: drink whenever thirsty. The sensation of thirst is a mechanism to alert the agency warns that excess fluid is lost and needs to be hydrated, so it is necessary to drink but in small amounts and for short periods, must never drink liters of water or stroke isotonic drinks.
But many runners may distrust their thirst. Some people may be thirsty and yet maintain adequate hydration to finish the training. To easily calculate how much fluid you should drink as runner can carry out the following checks before running:
- Weigh yourself naked before training.
- Keep an intensity of competition for an hour, which is the average time to find out what our sweat rate, i.e. how much fluid lost in that time.
- Measured in millimeters how much fluid you need at that time.
- Weigh yourself naked after the race and subtract that obtained before training. Throw in the amount of liquid that you need and get your sweat rate.
- Divide your sweat rate four to get the amount of fluid you should drink every 15 minutes of running.
Sweat rate changes depending on the humidity and heat, so it is advisable to repeat this exercise on days with different weather conditions to find out how much fluid to drink as the weather. If you weigh yourself after training to have gained a few grams it means that you drank too much and can fall in hyponatremia.
After training the habitual food intake and liquids should be used to restore moisture balance, but if not we should drink a liter and a half of water per kilo of weight lost. In these situations are recommended isotonic drinks or energy high in sodium intake and even salty snacks to stimulate thirst.
In addition, to this way of calculating the amount of fluid we need are some general guidelines. So in the case of running runners weighing up to 50 kg should drink 430 ml of water during a race of 8.5 km and a quart if it is 15 km, taking into account an average temperature of 18°C. If our weight is up to 70 kg these amounts of liquid are 650 ml and 1 liter and 250 ml respectively. Weighing up to 90 kg will be 860 ml and 1 liter and 850 ml. We must bear in mind that at higher temperatures need even more fluid and our clothing and humidity also influences our physical condition, but hydration is essential for good performance.