May 17, 2017 4 min read

I came across an article the other day, this one was on a Triathlete’s guide to salt and while I applauded the writer for mentioning salt (sodium) and it’s importance, the information that was provided didn’t really cover all that it should have.

I am working with quite a number of athletes leading into the Ironman World Championships in Kona this year and given how important hydration is in this event, it’s not something that you can take lightly. I want to give you three examples of athletes that I am working with so you can get an idea of the different sweat rates and varying sodium concentrations in their sweat. The numbers highlight how contrasting each individuals needs are and hopefully gets you thinking a bit more about how important it is to have an understanding of your own numbers. While this information is specific to this event any athlete that is preparing to compete in heat and humidity will get a lot out of the blog post.

Before I start it’s important to think about these articles on sports nutrition and liken them to a piece of your sporting equipment….ask yourself the question is this information specific to me?. What this article didn’t make clear is that some of you will naturally prefer and perform better in hot/humid conditions compared to others and the need for sodium varies massively between individuals.

Having tested sweat rates and the sodium concentration of that sweat of over 500 athletes you build a strong understanding of which athlete will prefer certain environmental conditions.

In hot/humid conditions an athlete with a low sweat rate and low sodium concentration in their sweat will be able to minimise their percentage of loss far better than an athlete with a higher sweat rate and/or higher sodium concentration.

Here are those examples of athletes preparing for Kona – keep in mind it’s likely to be hot and humid. Athlete number 1 has a sweat rate of around 1.6 litres per hour with a sodium concentration of 356 mg 1 per litre of sweat (the lowest sodium concentration I have seen to date). So each hour she will be losing 1.6 X 356 mg = 569 mg per hour based on the sweat rate in the conditions that Kona is likely to be. Without putting too much pressure on this athlete, these numbers are very exciting and she will be able to manage her sodium losses quite easily. In regard to her sweat rate the key there is to find the maximum comfortable amount of fluid her stomach can tolerate per hour in an attempt to bridge the gap between how much fluid she loses and how much her stomach can tolerate. As a side note the sodium concentration of your sweat is a number unique to you and does not change – more on that at Sweat. Think. Go Faster

Athlete number 2 has a sweat rate of 2.1 litres per hour and a sodium concentration of 850 mg per 1 litre of sweat. His sodium loss will be 2.1 X 850 mg = 1785 mg per hour . That’s 5 times the amount of sodium per hour compared to athlete number 1. You might think that’s a lot of sodium to lose per hour, but in fact it’s quite a good number in hot/humid conditions and quite manageable if you are separating your calories from your hydration. The key for this athlete, as for athlete number 1, is to ensure he can consume enough fluid per hour in an attempt to bridge the gap between how much fluid he is losing per hour and how much his stomach can tolerate per hour.

Now for athlete number 3 he has a real battle on his hands, when compared to athlete 1 and 2, due to his sweat rate being 2 .4 litres per hour with a sodium concentration of 1946 mg per 1 litre of sweat. That’s a whopping 2.4 X 1946 mg = 4670 mg of sodium per hour.

Athlete number 3 is losing 8 times the amount of sodium per hour than athlete number 1.

How do you even get close to addressing those losses? Sorry to keep going on about this but separating your calories from your hydration is the answer. If you are still relying on calories in your drink and then having to supplement with salt tablets because the sodium content of these sports drinks aren’t addressing your needs, it might be worth thinking about how separating your calories from your hydration might benefit you.

All these athletes will require a specific hydration plan to suit their own needs and athlete number 3 might have to consider reducing his intensity on the bike in an attempt to reduce his losses, which will in turn reduce the accumulative loss of sodium. Or hope for cooler conditions that are likely forecasted. If his sweat rate dropped to 2.0 litres X 1946 mg = 3892 mg per hour it will make it a little easier to minimise percentage of loss. Athlete number 3 clearly is at a disadvantage compared with athlete number 1 and 2 , but you just have to work with the cards you are dealt because what I have recognised over the years is that athlete number 3 will likely perform better in colder conditions and be able to get his revenge on the athletes who are light sweaters with low sodium concentrations, who generally don’t perform well in the cold.

You have a unique physiological makeup with specific needs and it’s important you consider this when reading articles on sports nutrition. If they are providing a one-size-fits all solution it’s likely not directed at you.