Sweating, and the resulting evaporation of sweat, is an indispensable ally for humans, especially athletes. It's a disaster if it doesn't happen: it allows us to reduce the excess heat produced by the body during exercise . This mechanism is activated through the natural thermoregulation process, absorbing a considerable amount of heat (2430 kJ/l) and thus cooling our bodies.
The consequences of sweating
However, through sweating, we lose a certain amount of minerals: primarily sodium and chloride , and also some potassium and magnesium . The greater the exertion, ambient temperature, humidity, and solar radiation, the more profuse the sweating will be, and with it, the loss of these minerals. When losses are significant, it is necessary to replenish them to avoid various problems.
Sodium: how much is lost through sweat?
The most abundant mineral in sweat is sodium. Consider that potassium has a concentration 6-8 times lower than sodium, and magnesium a whopping 100 times lower. Tangible evidence of sodium in sweat is the white stains we see on clothing, particularly around the neck and armpits: the more visible they are, the less the athlete has adapted to the ambient temperature in which they train or compete.
What happens in case of sodium deficiency
Sodium deficiency can lead to serious consequences. In extreme cases, it causes hyponatremia , a condition that occurs when blood sodium levels are particularly low. It can be caused by high sodium losses through sweat, excessive intake of mineral-poor water, or a combination of the two. It can manifest itself with further profuse sweating during and immediately after exercise, and for up to 24 hours afterward.
Hyponatremia is certainly the most dangerous consequence to manage, but it's not the only one. Sodium deficiency also reduces the intestine's ability to absorb water, resulting in increased intestinal stress during exercise and reduced hydration. Sodium is primarily absorbed in the ileum, the final section of the small intestine.
How to maintain sodium levels during training and competition
Athletes can rely on various products to prevent sodium deficiency. We can choose from powdered mixes, effervescent tablets containing electrolytes, or capsules containing only sodium chloride. In recent years, the evolution of sports nutrition has led to the development of increasingly practical and diversified solutions. Alongside traditional supplements, sodium-enriched ready-to-drink beverages are now available, particularly useful for post-exercise recovery, especially when fatigue or a reduced appetite make sodium replenishment difficult to achieve. The product range has also expanded to include sodium-containing energy bars and sodium-enriched energy gels, including those with neutral flavors. Having a variety of options can be an advantage in long-distance endurance sports, where sodium losses progressively increase and so-called "gustatory fatigue"—a reduced tolerance to consistent flavors throughout a performance—can develop.
Alongside formulas that provide both carbohydrates and sodium, there are also zero-calorie electrolyte-only products that dissolve in water. These solutions allow you to replenish sodium without providing additional energy and can be particularly useful during moderately long or intense activities performed in hot conditions, where maintaining hydration is a higher priority than energy replenishment.
Sodium and muscle crampsSodium is often associated with muscle cramps. While its effects on muscle contraction are undeniable, it's still unclear whether it's linked to exercise-induced cramps. The causes of cramps may be varied. While it's true that this type of cramping is more likely to occur in hot conditions, prolonged exercise, and dehydration, it's not proven that sodium loss is the cause. Heat itself, exercise-induced fatigue, and dehydration could all play a role, particularly in the nervous system. |
Two tips to improve performance
The variety of mineral supplements available allows you to use your training to identify the best solution for your individual characteristics and the environmental context in which you'll compete. In any case, it's important to remember that the solution will be the one that promotes optimal gastric emptying and intestinal absorption. In particular, we must keep in mind:
- Timing , or the timing of your drinking: the general recommendation during exercise is to take small sips of about 150 ml every 15 minutes , consistently. If you're sweating profusely , you'll need to drink more frequently, about every 10 minutes. Don't wait until you're thirsty, but, whenever possible, anticipate it.
- Heat acclimatization reduces sodium losses through sweat: sodium concentration in sweat can decrease by approximately 20-60% compared to a non-acclimated individual, although the extent of the reduction varies considerably between individuals. Why this discrepancy? The reason is simple: a non-acclimated runner's sweat is more concentrated in minerals than an acclimated athlete. Acclimatization allows us to reduce the amount of sodium lost through sweat. In general, athletes who adapt to the climate (temperature and humidity) can improve performance on the hottest and most humid days. This process takes 7 to 14 days, during which the body, to acclimate to the increased temperature, increases blood volume, which contains a lot of water, reducing the heart rate and increasing the amount of sweat.
To summarize:
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Bibliography
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- Sawka, N.M., Montain, S.J. - Fluid and electrolyte supplementation for exercise heat stress . Am J Clin Nutr August 2000 vol. 72 no. 2 564s-572s.
- Noakes, T. - Lore of running . Ed. Human Kinetics, 2003.
- Baker, LB - Physiology of sweat gland function: the roles of sweating and sweat composition in human health . Temperatures (Austin). 2019;6(3):211-259. doi:10.1080/23328940.2019.1632145.
- Baker, LB - Sweating rate and sweat sodium concentration in athletes: a review of methodology and intra/interindividual variability. Sports Med . 2017;47(Suppl 1):111-128. doi:10.1007/s40279-017-0691-5.
PLEASE NOTE: The information provided is for informational purposes only and is not intended to replace the advice of your doctor or healthcare provider. The information is intended for healthy individuals; any diet or exercise program must be supervised by a qualified professional before beginning it, in accordance with Italian law. Enervit SpA assumes no liability, as the information is for informational purposes only, and interested parties should consult their trusted healthcare professional before undertaking any diet or exercise program.