Ironman Race Day Salt Supplementation

Hyponatremia means roughly “low salt levels”, and can be brought on by decreased ingestion of sodium or by increased intake of sodium-free or sodium-low fluids. In effect, hyponatremia is a state in which your body’s electrolytes are too dilute. In extreme cases this can lead to death.

 In milder forms, the condition rears its ugly head in the form of swelling of the body as fluids move from the cells into the interstitial fluid in an osmotic effect, nausea, cramping, fatigue in part due to a reduced ability to metabolize carbohydrates, a swollen stomach as fluids remain trapped in the stomach because digestion is interrupted, and so on.
Mild hyponatremia is not a severe condition, but if you are not aware of the causes and effects of hyponatremia the condition can worsen, especially if you consume more and more water to compensate for symptoms that inexperienced athletes can easily misdiagnose as dehydration.
There are plenty of athletes who take extra salt both preceding and during a major race, with Hawaii being the most obvious location where extra salt should be taken in prior to the start.
In one famous instance of a hyponatraemia-induced meltdown, Jan Ripple, another famous member of the Death March Club, in her comments after a mid-80’s Hawaii race she was leading until about mile 20 of the run until she collapsed, made the comment that she didn’t know why she fell apart late in the race–“I drank 12 large bottles of water on the bike . . .”.
In effect, Jan diluted her electrolyte levels by drinking too much sodium-free fluid (water) without compensating by taking in more salt. In especially sever conditions in Lanzarote 1997, Paula Newby-Fraser observed that many athletes pee’d away their minerals and electrolytes by drinking to much in hydrating before the race without consuming extra electrolytes along with the fluids. From my experience in listening to the experts, the evidence is that salt and electrolyte loading prior and during an Ironman is crucial if you want to succeed.
 2010 Ironman World Championships in Kona. A very hot & humid day. Windy!! I bonked on the bike (mile 70) but still finished 25th Pro in 8h42min. Racing in kona is always really hard and it hardly ever goes according to plan.
Extra salt helps–a lot. Especially during training when you are lacking sleep.
Have you ever found that your body tends to swell up?–water seems to be retained in the interstitial fluid instead of in the cells. Extra salt helps restore the balance and encourages the body to eliminate the extra fluids–which runs contrary to what one would think. Truth is, if the body is lacking salt, you will swell up like a balloon as water moves out of your cells and into your interstitial fluid.
If you are sweating copiously such as in a race like Hawaii (or Brazil, Lanzarote, Malaysia, etc.), it takes TWO LITRES of Gatorade per hour to replace the salt you are losing. About 1/2 a TABLESPOON of salt is lost PER HOUR! Think about that. That’s more than the average DAILY suggested consumption. Per hour. For at least 8 – 9 hours (if you include a warm swim!), and many more for later finishers.
Since you aren’t going to absorb every bit of salt that you consume, I think this amount of salt (and consequently the volume of Gatorade) that you need to consume is in fact too low. You need more than what’s lost to be able to replenish your electrolytes, because inevitably you will metabolize some during absorption, and due to inefficiencies some will not even be absorbed.
There is a catch, however, and that is: you can absorb only up to about 800mL per hour of fluid per hour–and that’s if you’re a big person–meaning that there’s no way you can get even 1/2 the salt that you lose per hour (on a hot, long day) from drinking Gatorade electrolyte drink alone. You should not try to drink 2L of Gatorade per hour–one, you can’t absorb that much fluid, and two, you can’t grab and drink that much in one hour any way, not if you’re going hard. So you need to look elsewhere for another source of salt than just an electrolyte drink, especially if it’s a dilute electrolyte source or if the drinks have been improperly mixed and are too dilute.
Further complicating matters is the anti-salt health kick that was/is promoted so heavily in the past few years. Many people think that salt, per se, is unhealthy. This simply is not true–too much salt is unhealthy. However, the 1 teaspoon per day of salt that is recommended as a healthy amount to a couch potato! But, seriously, how much do couch potatoes sweat? Not a lot!!
An athlete in hard training needs more salt than the average person–in my view a lot more, such as double or triple the suggested amount (depending on how hard you’re training). In fact, if you are riding one of your long pre-Ironman bricks on an especially hot Saturday, you’ll be simulating race day conditions and you will need to consume extra salt to make up for what you lose in sweat (and blood and tears if it’s a tough day!).
For this reason I think electrolyte supplementation on your hard training days is important for Ironman athletes.
For these reasons I always suggest taking in extra salt in hard training for, just prior to, and during an Ironman. 


The statistics are simply too overwhelming to ignore-most Ironman events take place in extreme conditions, there are invariably many cases of hyponatremia as people tend to overcompensate for the heat by drinking too much plain water or dilute electrolyte solution.

Here are some preventative steps to take prior to and during the race.

This includes:

  • Increasing sodium intake in the 3 – 4 days leading up to the race
  • Consuming some salt with any plain water that you consume
  • Not over-hydrating prior to a race (yes, one can over-hydrate!)
  • Not over-hydrating during a race (see above!)
  • Consuming some form of ADEQUATE salt replacement during a race


Remember these two simple rules on race day to help balance electrolytes:

  • If the electrolyte drink available tastes too “watery” – take in more salts!

  • If the drink tastes too concentrated, take on more water!

Before every race, make sure that you know what the electrolyte drink will be for the race. If you are not familiar with the brand, compare labels with Gatorade, which has about 1/2 to 1/3 of the salt required to fully replenish a heavy sweater’s sodium balance during an Ironman held in extreme conditions.

If it’s Gatorade, depending on your weight, you will consume anywhere from 3-10 300-600mg salt tablets during the bike, or about 1 – 2 per hour. (Idea: Leave one piece of Powerbar on your bike just to stick on salt and Tums for consumption later in the race).

Try to consume all solids (if you can handle solids that is) in the first 2/3 of the bike. You can also add some electrolyte powder (by opening and dumping capsules) into your drinks at the beginning and special needs drinks that you pick up at the 1/2 way on the bike.
Try to get in a few tablets if you can remember during the run, but if you’ve consumed all of the bike salt you should be ok for the marathon. Yes, it tastes very terrible to chew on an extremely salty Powerbar, but in my view it’s an Ironman and not a banquet, so who cares!
If that doesn’t work for you, you also just swallow the salt tablet whole and wash it down with water or electrolyte drink.
Compare your electrolyte drink of choice to Gatorade and see how the sodium levels match up. If you are a heavy sweater, think about the equivalent amount of salt that is in 2L of Gatorade that you’ll need per hour and if you are getting enough from your drink to meet your needs. If you’re not acclimatised to the extreme conditions in which a race your Ironman will be held, assume that you will be a heavy sweater on race day regardless of your experience in training.
Keep in mind that for a well-trained athlete, it takes a full three weeks to acclimatise properly to hot and humid conditions –if you can’t prepare adequately for the heat (Heat training protocol), consider taking in extra salt on race day.
Keep in mind that many inexperienced athletes in fact START an Ironman in a slightly hyponatremic state. They feel puffy, full of fluid, groggy and a little slack in general, often feeling as if they haven’t tapered right (which is another issue in and of itself!).
In fact, these athletes have probably been cutting back on salt intake as part of their general diet and although their bodies have adapted to it, when it comes time to hydrate for the race they fail to increase their salt intake along with their increased fluid/water intake.
Consequently they end up diluting their body’s electrolyte levels, creating an imbalance that can effect proper nervous function, muscular contraction, carbohydrate metabolism and digestion to varying degrees.
If you haven’t done the math on the ~600mg salt tablets to know how much salt is right for you.
It will be a trial and error process, with some extra salt being better than none.

Extra salt is a necessity to performing well in extreme conditions in long endurance events, and for that reason I suggest you always make sure that your heavy training, pre-race, race, and post-race nutrition for Ironman events held in extreme conditions include extra salt to cope with the demands that you will place on your body on race day.

Please keep in mind that I’m not a nutritionist. I suggest to consult with one and to use the above as a starting point or inspiration -if you like- to become pro-active in planning your own race nutrition (water intake, salt intake, food intake (solid,semi-solid, liquid).