Sodium plays an important role in body function as it helps maintain fluid balance and cognitive function. Therefore, if your sweat loss is truly cumulative, it's important to replenish some of the sodium you're losing.
Why Sodium Is Important
A 2015 study found that athletes who adequately replenished sodium lost through sweat completed a middle-distance triathlon an average of 26 minutes faster than those who did not.
This kind of performance boost isn't for everyone, but it highlights the potential impact of proper drinking strategies.
Your body contains a lot of water - in fact 50-70% of it is made up of water, depending on how much muscle and fat you have. 1 is found outside cells, in extracellular fluids such as blood.
What Does Sodium Do?
The main electrolyte in this extracellular fluid is sodium, and much of the body's total sodium reserves are located here. It is directly related to the amount of sodium in the body. So more sodium means more liquid. Less sodium means less liquid.
In addition to maintaining fluid balance, sodium plays an important role in nutrient absorption in the gut, maintenance of cognitive function, transmission of nerve impulses, and muscle contraction. Most of the sodium we eat comes in the form of sodium chloride, or common table salt found in foods and drinks.
Today, we take salt for granted because we have developed methods to make it widely available. However, wars have been fought over salt access and control in the past. This gives us a pretty big clue about the importance of salt for life!
Your body cannot produce or store sodium past a certain point, so you must consume sodium daily to keep levels replenished.