Suor, sódio e eletrólitos

Sweat, sodium and electrolytes

Sweat, sodium and electrolytes

Hey guys! With summer arriving, the temperature rises and soon, so do the sweating (or sweating) rates! Do you know what we missed in it? Is it possible to reset everything? In this post I'm going to start the subject and tell you!

During exercise, the body experiences several physiological adaptations. One of these adaptations is sweating, which regulates body temperature and eliminates unwanted substances. However, sweat also leads to the loss of essential electrolytes, including sodium, potassium and magnesium, which are fundamental to the functioning of the body during physical activity. And before talking about replacing them, I think it's important to first explain the subject, understand what happens to the body and why it's important to replace them. Let's go!


During physical activity, increased metabolic demand generates heat. To prevent overheating, the body uses sweating as a cooling mechanism. Sweat is mostly water, but it also contains electrolytes, with sodium being the predominant electrolyte. The evaporation of sweat from the skin helps dissipate heat, regulating body temperature.


Sodium is an essential electrolyte for several body functions, including blood pressure regulation, muscle and nerve function, and fluid balance. During physical activity, sweating can lead to significant sodium loss, which can be harmful if not compensated adequately. The amount of sodium lost in sweat varies from person to person and depends on factors such as exercise intensity, ambient temperature, clothing and sweating rate - some even fall into “excessive sweating” and these cases need to be individualized. Important detail: sodium retains hydration, preventing the body from dehydrating and the athlete from “breaking down”. And for this to happen you need to consume sodium and of course, water! A sodium deficiency can lead to dehydration and a decrease in the body's ability to regulate temperature. Additionally, a lack of electrolytes can cause muscle cramps and early fatigue.


Chloride is another important electrolyte that plays a significant role in maintaining acid-base balance and regulating the osmotic pressure of body fluids. During physical activity and sweating, chloride can be lost in varying amounts, along with sodium. Although chloride loss is rarely the main focus, it contributes to electrolyte imbalance and can affect performance and health, especially in athletes who sweat a lot.


Magnesium is also an essential electrolyte for muscle function, acting in muscle contraction, transmission of nerve impulses and energy production. During activity, magnesium demand may increase, and loss of magnesium through sweat is a concern. Magnesium deficiency can lead to changes in gastrointestinal, cardiovascular and neuromuscular function. Physical exercise can deplete magnesium, which, together with a relatively low dietary intake of the mineral, can impair the efficiency of energy metabolism and exercise capacity. It is generally not recommended to consume high doses of magnesium in supplements during practice as undesirable gastrointestinal symptoms may occur.


Last but not least: Potassium . Extracellular and intracellular potassium concentrations in skeletal muscle influence muscle cell function and are also important determinants of cardiovascular and respiratory function.

Several studies over the years have shown that exercise results in a release of K+ ions from contracting muscles, which produces a decrease in intracellular K+ concentrations and an increase in plasma concentrations. After exercise, there is a recovery of intracellular K+ concentrations in previously contracted muscle and plasma K+ concentrations quickly return to resting values.


Furthermore, a blunting of exercise-induced hyperkalemia (excessively high blood potassium levels) in trained individuals is associated with a decrease in net K+ loss through muscle contraction; these observations were attributed to an upregulation of Na+-K+ pump activity in both inactive tissues and active muscles. Potassium loss through sweat is relatively smaller than sodium loss, but it is still relevant, especially in prolonged and intense activities.


Loss of these electrolytes during physical activity can affect performance and health, making it important to monitor and replace these electrolytes as needed based on the type and intensity of physical activity.

Keep in mind that individual electrolyte needs may vary, and consultation with a healthcare professional or sports nutritionist may be helpful in determining each person's specific electrolyte replacement needs.


In the next posts I will delve deeper into the subject. See you later!

Gabi from Z2

References:

Goulet, E. D. (2012). Dehydration and endurance performance in competitive athletes. Nutrition Reviews, 70(Suppl 2), S132-S136.

Shirreffs, S. M., & Sawka, M. N. (2011). Fluid and electrolyte needs for training, competition, and recovery. Journal of Sports Sciences, 29(sup1), S39-S46.

Maughan, R.J., & Shirreffs, S.M. (2010). Development of individual hydration strategies for athletes. International Journal of Sport Nutrition and Exercise Metabolism, 20(5), 457-472.

Convertino, VA, Armstrong, LE, Coyle, EF, Mack, GW, Sawka, MN, Senay, LC, ... & Vogel, JA (1996). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 28(1), i-vii.

Bohl CH, Volpe SL. Magnesium and exercise. Crit Rev Food Sci Nutr. 2002;42(6):533-63. doi: 10.1080/20024091054247. PMID: 12487419.

Nielsen, F.H., & Lukaski, H.C. (2006). Update on the relationship between magnesium and exercise. Magnesium Research, 19(3), 180-189.

Potassium Regulation During Exercise and Recovery. Michael I. Lindinger, Gisela Sjagaard. Sports Medicine II (6): 382-401. 1991