Do You Need Salt Tablets?

Oct 28, 2021

Many endurance athletes take salt tablets, but do we really need them? I spoke with the sodium and hydration master aka Alan McCubbin to break down everything you need to know about sodium, hydration and endurance exercise.

Here’s what we discussed:

Why is sodium is important for sports like triathlon?

  • When we sweat during exercise, sodium is the main mineral we lose along with chloride
  • The main electrolyte in our blood is also mainly sodium, and this plays a big role in moving water around the body

 Are there currently any guidelines around sodium replacement?

  • The guidelines are currently very vague
  • There aren’t really any specific guidelines around sodium replacement during exercise apart from a broad statement from the American College of Sports Medicine indicating that people should replace sodium when large losses occur, but they don't define what a large loss is

What research is currently underway to find some answers?

  • A study to survey what athletes think about sodium found that the majority of endurance athletes tend to think that because they sweat a lot, they need to consume a lot more sodium than the general population on a day-to-day basis however
  • We know that loading up on sodium a few days before a race affects sweat sodium loss during the event. The study found that it affected sweat sodium by around 10-12%

What happens if we over replace or under replace sodium during exercise?

  • Our blood sodium will increase during exercise as no matter how salty our sweat is, it’s always less salty than our blood
  • Blood sodium will only decrease if you are excessively drinking water or exercising for  more than 10+hours
  • Hyponatremia can occur if you’re over replacing fluid losses. Example - if you're replacing 80-90% of your fluid losses and not having any sodium over a long period of time (ie. Ironman & Ultra marathons)

  • You don’t need to replace sodium via tablets/capsules if you are doing less than 10 hours of exercise as your body has enough stores to get you through
  • You don’t need to replace 100% of your sodium losses either - somewhere between 25-50% is all you need to replace for ultra-endurance events
  • You must have a planned strategy rather than just popping capsules for the sake of it 


Does it matter what form sodium replacement is in? For example sports drinks vs tablets vs capsules?

  • You can replace sodium with food, drinks, and gels – it doesn’t have to be capsules or tablets
  • Capsules with a particular coating dissolve immediately once they hit the stomach, releasing a large amount of salt in a short space of time and will cause nausea and vomiting
  • Sodium in food is padded out and less concentred therefore it is easier on the stomach
  • The form of sodium doesn’t necessarily matter as long as it’s controlled and tolerated, and strategic 

What role does Sweat Testing play in all of this?

  • Anything less than Ironman distance for a triathlon is probably unnecessary for sweat testing because you're unlikely to replace fluid to the extent where a significant amount of sodium is going to be necessarily that helpful for you
  • Sweat sodium losses during exercise can vary quite a bit in the same person (up to 15%) and
  • Sweat sodium loss at one measured site of the body doesn’t reflect what’s going on over the whole body. A qualified practitioner can use scientific regression equations to estimate whole-body sodium
  • Most importantly, understanding and interpreting your results from sweat testing and then applying it to you specifically and your event is going to be the most beneficial

To go deeper, listen to the Triathlon Nutrition Academy Podcast Episode 14: Do you need Salt Tablets with Alan McCubbin for more!


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