Why is sodium critical to athlete performance?
Why is sodium critical to athlete performance?
Sodium plays a key role in your body's functions, helping to maintain hydration and cognitive function. That's why it's important to replace some of the sodium you're losing when your sweat losses really start to spike.
Why Sodium Matters
A 2015 study found that athletes who adequately replaced sodium lost through sweat completed a middle-distance triathlon an average of 26 minutes faster than those who didn't.
While this type of performance boost isn't possible for everyone, it shows the impact proper hydration can have.
Your body contains a lot of water - depending on the muscle and fat percentage, it consists of 50 to 70% of this substance. About a third of this water is outside of your cells, in extracellular fluids like your blood.
What does sodium do?
The main electrolyte in this extracellular fluid is sodium, and a majority of your body's total sodium stores are located here. This makes them quite "salty," and the total volume of extracellular fluid in your body is directly related to the amount of sodium you have on board at any given time. So more sodium means more liquid, less sodium means less liquid.
In addition to regulating fluid balance, sodium plays an important role in the absorption of nutrients in the gut, maintenance of cognitive function, transmission of nerve impulses, and muscle contraction. Basically, it's damn important.
We get most of our sodium in the form of sodium chloride, the common salt found in food and drink.
Today we take salt for granted because we have developed ways to make it available everywhere. But in the past, wars have been fought over access and control of salt, which gives you a pretty good indication of its importance to life!
Because your body can only produce or store salt up to a certain point, you must consume sodium daily to maintain your levels.
There are individual differences, as athletes primarily lose sodium and fluid during training. Because of this, those who exercise regularly have different sodium requirements.
Everyone loses a different amount of sodium with sweat. At le melo we see athletes losing anywhere from 200mg of sodium per liter of sweat to as much as 2,000mg/l. I personally lose ~1,800 mg/L and as a result often suffered from hydration issues in hot climates (I'm frequent in Turkey and Portugal). It was my personal search for a solution that led me to start the company.
Of course, the amount of sweat also varies from person to person and situation to situation (ranging from almost nothing in cooler conditions and low intensity to several liters per hour during intensive sports in the heat).
When you combine differences in sodium concentration with differences in sweat rate, the potential differences in net sodium losses between individual athletes can be very large, especially in a middle or long distance triathlon.
And in many cases, those losses are many times greater than someone who doesn't sweat regularly. Therefore, athletes should be cautious about standard federal guidelines for sodium consumption. If you sweat profusely and sweat out a lot of sodium, it's more than possible to lose the state guideline-recommended 2,300 mg of sodium per day in just one hour of exercise. If you exercise for a long time, the loss can be really enormous.
What happens when sodium losses increase?
It's impossible to pinpoint the exact point at which sodium (and fluid) loss through sweating becomes a problem for an athlete. However, it is clear that at a certain point the losses can have a detrimental effect on your performance.
Your blood volume gradually decreases as your sweat loss increases. This is because the sweat is extracted from the blood plasma. This puts more strain on your cardiovascular system and makes it harder to pump blood to cool your skin and working muscles.
Other problems such as a general feeling of fatigue and muscle cramps can also occur if losses go uncorrected long enough or if there is a significant fluid and sodium imbalance.
Up to a point, just drinking plain water is enough to make up for sweat loss. But as these losses increase, you also need to replace sodium to keep your blood from thinning.
This is a potentially catastrophic condition called hyponatremia that can ruin your race and, tragically, sometimes be fatal.
How Much Sodium Should You Replace When You're Sweating?
Because sweat/sodium losses are so individual, general guidelines for sodium and fluid replacement should always be taken with caution.
However, figuring out whether your net losses tend to be small, moderate, or large is a good starting point for determining the amount of sodium and fluid that works best for you under different circumstances.
The two most important factors that determine your personal net sodium loss are...
- The total amount you sweat. It depends on your sweat rate and the number of hours you sweat over a given period of time.
- Your sweat sodium concentration, ie how much salt you lose through your sweat.
To find out what these values are roughly, it makes sense to start with that.
Calculating your sweat rate can be a little tricky, but here's a guide to help you get a reasonable estimate of how much you're sweating per hour.
The sodium concentration in your sweat is largely genetic and varies little. This means that you can only find out by taking a sweat test, which in most cases you only have to do once.
Bestzeit offers a non-invasive sweat test that will help you find out exactly how much you're losing. → https://sweatpack.bestzeit.com/