It is finally the best period of the year when we can have together, a great outdoor fitness training session in Berlin! But what about drinking and recovery? Get to know everything you need here:
Changes in body weight indicate the amount of water lost during exercise and the adequacy of rehydration during and after exercise.
Heavy sweating is the cause of electrolyte loss during physical activity.
However, the sweat flow and the electrolyte content of sweat (Sodium, Potassium, Chloride, Calcium, Magnesium), which vary greatly from one individual to another, have an influence on the composition of sweat.
When perspiration increases, the sweat content of sodium and chloride ions increases, while that of potassium and magnesium ions remains unchanged and that of calcium decreases. It is the loss of the sodium and chlorine components that is most likely to be the cause of the perspiration deficit.
It is clearly recognized that temporary mineral deficiencies can occur during prolonged exercise. Therefore, compensation for losses is recommended for long-lasting sports.
Because of its stimulating effect on the absorption of water in the intestine, the addition of sodium to a carbohydrate drink is generally justified.
It has been shown that rehydration drinks, with the addition of sodium chloride, are better able to correct the water imbalance and plasma volume – through water retention – than still water.
If the rehydration drink does not contain enough sodium, the excess liquid absorbed will simply increase the volume of urine excreted, bringing no benefit to the rehydration process. These authors conclude that drinking a large volume of water after exercise cannot be a compensatory parameter for dehydration if the amount of sodium is not high enough, and vice versa.
Moreover, moderate exercise causes only negligible losses of potassium in sweat. On the other hand, during more intense exercise (e.g. during a competition), more potassium is lost in the sweat. Higher losses of potassium can be compensated for by eating potassium-rich foods (lemon, banana, etc.). A glass of orange or tomato juice replaces practically all the potassium, calcium, and magnesium lost in about three liters of sweat.
Alkaline “sports” drinks and recovery
In the case of the sporting activity, the acid-base (pH) imbalance in the blood disrupts both the endocrine system, the availability of energy substrates in the muscles and blood, the cardio-circulatory, and ventilatory systems, as well as the subjective perception of fatigue.
Thus, for about twenty years now, the practitioner of rather anaerobic sports (intense and short duration, or repetition of intense and short duration effort) has been advised to use alkaline drinks after intense effort, in order to shorten the recovery time of acid-base homeostasis.
Carbohydrate drinks and recovery
However, a certain degree of dehydration remains unavoidable during physical activity (especially when carried out in a hot environment), so recovery must be used to optimize the possibilities of restoring the hydro mineral balance.
This is the particular concern of sportsmen and women involved in events where efforts are repeated at short intervals (such as in triathlons, decathlons, or when there are repeated fights or assaults on the same day).
It is well established, however, that there is a prolonged period after a state of dehydration during which the sportsperson will not be able to restore 100% of his or her water capital.
It appears that the ingestion of carbohydrate solutions (CHO) during the recovery period allows exercise capacity to be restored more effectively than the ingestion of water alone. This is important when the recovery interval between two repetitions is short or when exercises are repeated over several days.
With regard to the content of carbohydrates, or carbohydrates (CHO), for recovery, glucose is often preferred and has been shown to be effective, due to its absorption, which is an active process.
Recommendations in favor of hydration during recovery:
Replace body fluids lost during exercise as quickly as possible by drinking. To be very accurate, weigh before and after to determine the athlete’s water needs. Complete fluid replacement and retention can only be achieved by ingesting 150-200% of the measured fluid deficit.
■ Athletes’ rehydration, guided by a sensation of thirst, is always insufficient to compensate for the water losses linked to the practice of exercise. In this case, fresh water at 12-15 °C and lightly flavored can really help to increase water intake compared to other drinks (cold water, warm water, mineralized water). The palatability of rehydration drinks is important in order to stimulate their intake, but whenever possible, preference should be given to the intake of electrolytes in the solid food, in order to reduce the sodium concentration of the drink.
■ Faster restoration of the water balance is achieved if large volumes (rather than small volumes of liquid) are ingested quickly, over a longer period of time. After this ingestion, it is recommended that the intake be split at a rate of 200 ml every 15 minutes.
If the athlete has at least 6 hours before the next training session, water balance can be achieved by combined ingestion of water and solid food.
■ If the time between two training sessions or competitions is too short to allow for the ingestion and digestion of a meal, and rehydration must be achieved by the ingestion of liquid alone, the solution should contain a minimum of 50 mmol.l-1 (1.15 g.l-1) of sodium and, if possible, a small amount of potassium if this is not provided by the diet.
■ In addition, a carbohydrate concentration of approximately 2% can improve intestinal absorption of water and sodium.
The ingestion of salt tablets should be prohibited because of the hypertonicity they would cause in the intestinal lumen, leading to an increase in digestive secretions and the possible occurrence of digestive disorders.
■ The ingestion of caffeine during recovery should be avoided as it increases the excretion of electrolytes in the urine (Mg2+, Na+, and Ca2+).
■ Ingestion of drinks with a glucose concentration exceeding 2.5 g/100 ml slows down the speed of gastric emptying. The addition of sodium or potassium chloride, often in excess, in exercise drinks has no effect on the speed of gastric emptying.
■ Mineral concentrations for optimal restoration of plasma volumes with stable osmolality should be 0.5 to 0.6 g.l-1 for Na+, 0.7 to 0.8 g.l-1 for Cl”, and 0.1 to 0.2 g.l-1 for K+.
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