Hydration Series - Sodium & Optimal Performance

Hopefully by now you’ve looked at our “All About Salt/Sodiumarticle. This should lay the foundation and the groundwork for how sodium works in the human body.


Now that we know the basics, how can we use it to fuel athletes to their best performances?


When we look at the research, specifically citing this study (1) from 2015, we can see the huge improvement in performance when sodium is replaced at an appropriate rate and dose. How much does it help?


Those who supplemented with sodium and more closely met needs ran the event almost a HALF HOUR faster than the control group… Yea... that’s a lot.  


The goal for the rest of this article is to explain WHY it works and HOW to use it for your performance and needs.

What makes sodium so important to performance?


The biggest factors are that sodium does not only do 1 thing in the body, but really it impacts many important roles in the body. Here are some examples of what is affected and how Sodium helps:


Absorption of nutrients in the gut

  • Sodium’s ability to aid here plays a major role in gut comfort. Any athlete, specifically long duration or distance ones, will tell you about gut rot. This is a terrible feeling where the fueling was not right for the training or competition. The absorption of nutrients from anything the athlete eats or drinks will help to make sure they can process and use these to be able to better perform.
  • Take home - Sodium intake is important not just immediately pre or mid higher intensity or long duration exercise, but the diet leading up to and after as well.


Sustain or improve cognitive function

  • During high intensity exercise the body shunts blood from the gut and brain to the working muscles. When this happens, the nervous system and the brain function at lower levels. Sodium can help with the fluid balance and also with making sure the blood does not thicken, which makes it harder to pump.
  • If hyponatremia sets in and the lack of sodium from dehydration, it can lead to major issues or disaster.
  • Take Home - the true culprit is the lack of balance in the cells between potassium and the sodium which disrupts the normal function due to dehydration. 


Nerve function

  • Similar to the cognitive function, sodium plays a major role in the bodies ability to work on the CNS. The sodium level plays a role in the angiotensin activity. When this happens, it increases basal renal sympathetic nerve activity. The impact it has is shifting arterial baroreflex control to a higher level of arterial pressure. When this pressure is changed, it greatly changes blood pressure too.
  • Take Home - a person’s blood pressure can be affected greatly. This impacts not only performance, but the chances of passing out.


Muscular contraction.

  • Athletes like when their muscles work correctly… funny how that works. A lack of sodium or improper balance of it means that the muscles can’t contract at the appropriate rates and times in order to sustain pace, be explosive or win a big event.
  • Take Home - If you want to have that ability to compete well in the final half, period or quarter or finish the race strong, having the appropriate amount of sodium can help


Balancing Fluid in The Body

  • This is the real money maker. The ability to balance the intra and extra cellular fluids for working muscles, allowing athletes to improve performance. Sodium is the main electrolyte the blood, constituting 15-20% of the extracellular fluid, this is where most of it is stored. With the appropriate amount of sodium, the body is able to absorb and retain fluids drank while increasing blood plasma volume. This increase in volume means less stress on the cardiovascular system to deliver oxygen and dissipate heat, helping you to stay cool while working hard and perform at a higher level.
  • Take Home - balanced sodium levels and appropriate intake for your training or competition can lead to better overall performance since there will be the right balance of sodium in your blood. 


How do athletes lose sodium?

Any time you use the lavatory or sweat, you will excrete and lose some sodium. Like a lot of things, our diet is the only way to bring in the necessary amount. The human body will only store a set amount, for our health and performance reasons, and it also can’t create more internally.


Athletes are well known for sweating, and this is the most common way for them to lose sodium during competitions and/or training. This means that athletes or people who train, work out or compete more, have different sodium intake needs compared to a more sedentary population.


So, all athletes are the same for sodium needs right?




But, all athletes playing the same sport or doing the same event need the same right?




It’s important to note that each individual loses a unique amount of sodium while sweating. The normal range is between 200mg/liter of sweat all the way up 2,000mg/liter. This means some people need to replace 10x’s more sodium!


The people who sweat more often use terms like “Salty Sweater”. This describes a person who expels more sodium than most average people. You can usually pick them out at endurance events due to the white rings on a hat, t-shirt, etc.


It’s important to note here also that those who train more are also more likely to have developed the ability to expel more sodium as part of a training adaptation.


This makes it even more important to look at the sodium intake recommendations for the general population. While these may work for those who need to limit their intake after consulting a doctor, an athlete or person who works out consistently will be very different.

What happens when sodium gets low?

The longer a person is sweating, specifically during exercise, the more their blood volume decreases. This is due to the sweat being drawn from the blood plasma. Like we discussed earlier, as blood volume decreases, there is a much higher strain on the cardiovascular system.


Blood becomes harder to pump to the skin, (how we cool off via sweat) and decreases blood to the working muscles. You don’t need a PhD in exercise science to know that if you can’t regulate body temperature and your working muscles have less blood, you’ll perform worse.


We’ve already talked about the other issues that happen if this is not accounted for (fatigue, decreased concentration, performance, etc.). In a lot of circumstances with shorter duration work, or lower intensities with a moderate environment, consuming only water will be balance the sweat loss.


With longer events, as the sodium loss escalates, it becomes imperative to replace sodium so the blood doesn’t dilute. When this happens, that is what causes hyponatremia, we’ll talk more about that in other articles.


Just tell me how much sodium I need already!

Sorry, I am sure by now you just want the answers, but we believe in empowering and educating our athletes and clients. Because the sweat rates and amount of sodium lost are so individual, giving you a ballpark answer is tough. You should consider any google search results that tell you a specific number as a VERY rough estimate.


Your mom and dad have a huge impact on your sweat rate. Not just how nervous they made you when you were in trouble, but also the genetics they passed down. Your sweat rate is VERY driven by your genetic make up and only has slight variances.  On a positive note, this does mean that once you figure out your rate with a sweat test, you won’t have to redo it.


We recommend that our athletes who want to dive deeper into their sodium needs and sweat rate go see our friends at Precision Hydration. They offer an Advanced Sweat Test. This can be done without exercising and gives data on how much sodium you lose. We can take this data and then apply it to help you create a specific hydration plan. 


*Precision Hydration also offer a free online Sweat Test. This helps our athletes get started with and offers basic advice to use for bracketing your needs by experimenting with options. The biggest reason we recommend this brand/company is that their online sweat test has been peer reviewed at Sheffield Hallam University which lead to a published paper proving their efficacy. They are a company who are trustworthy and research based.


Want to learn more about hydration, nutrition or performance enhancement? Reach out for a FREE CONSULTATION with our Powell Performance staff to get started!


*NOTE – Powell Performance DOES NOT have an affiliation or agreement with Precision Hydration, we simply appreciate and respect their information and products and recommend our athletes use them if able.



  1. Del Coso J, González-Millán C, Salinero JJ, Abián-Vicén J, Areces F, Lledó M, Lara B, Gallo-Salazar C, Ruiz-Vicente D. ‘Effects of oral salt supplementation on physical performance during a half-ironman: A randomized controlled trial’. Scand J Med Sci Sports. 2015 Feb 14. doi: 10.1111/sms.12427

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