June 06, 2017 4 min read

When athletes who are having trouble with their energy levels, not feeling right or can’t seem to nail their race nutrition, contact me we go through a long list of questions to identify what the cause might be. Over the years I’ve refined that list and the more common the issue, the higher it makes its way up the list.

There could be a myriad of reasons why the athlete is not feeling 100% but through a process of elimination we work together on addressing each question.

Coconut water is in my top ten, specifically the packaged variety that some athletes have taken to as their preferred post training hydration. Some athletes even use coconut water as their hydration during an event. When making choices on what might work best for you, you need to be mindful that for every action there is a positive and/or negative reaction.

As an athlete you have a heightened awareness of how you feel, with an acute understanding of when your body isn’t functioning as it should be. Coconut water started to make its way up the list after athletes reduced their daily intake of coconut water to see if it made a difference to their performance. Every athlete experienced an improvement in how they felt and the lethargy, weakness and nausea that they had been experiencing subsided.

Why would coconut water cause a problem? Well for starters, coconut water (specifically the packaged variety) is high in potassium and while it’s an important mineral, you can have too much of a good thing.

The problem with packaged coconut water is potassium. Packaged coconut water, depending on the brand, contains between 135 mg and 240 mg of potassium per 100ml serving, which means a one-litre (1000ml) bottle/package contains between 1350 mg and 2400 mg of potassium. Some of the athletes that had contacted me were consuming 2 – 3 one-litre bottles of coconut water per day, which amounted to upwards of 4000 – 6000 mg of potassium per day, not including potassium from other food sources. They were training hard and that volume of fluid was certainly warranted post-training but when we calculated the levels of potassium they were drinking and discussed how much potassium they needed, they could see they had a possible explanation for why they weren’t hitting the numbers they were used to.

Depending on what literature you read the recommended daily intake of potassium for an adult can range between 1950 mg and 5460 mg per day. All the marketing was suggesting that these packaged coconut waters were the perfect hydration for athletes, not sure why given the low amount of sodium but it all sounded good.

I first recognised the impact too much potassium had on an athlete’s performance while formulating the Shotz Electrolyte Tablet. During early trials, we saw that too much potassium in the formulation impacted on power output and also increased the likelihood of potential stomach problems. I stumbled across this while trying to improve the palatability of the tablet. I lowered the amount of potassium because it gave a chemical aftertaste, which allowed me to increase the amount of sodium.

I didn’t think this would have an impact on anything but taste, but with less potassium, power outputs were more consistent and stomach issues lessened. So I started learning more about potassium and its impact on athletes.

Through the many sweat tests I have performed on athletes the results were showing that potassium losses didn’t vary that significantly between individuals with a loss of between 190 mg and 280 mg per one-litre of sweat. Not a big range when you consider sodium losses that I have seen range between 311 mg and 2314 mg per one-litre of sweat. This is reflected in the saline drip, which has around 195 mg of potassium compared with 3000 mg of sodium.

Too much potassium in the bloodstream can cause hyperkalemia (heart arrhythmia) and the use of coconut water (high in potassium) beyond what you actually require can be the cause of fatigue, weakness and nausea, three things athletes want to avoid.

If packaged coconut waters are your go-to drink, you should take a closer look at the nutrition information panel and monitor your consumption. (When analysing nutritional information for beverages, look at per 100ml serving amount, then times that number by the volume of the bottle/package.)

As a heads up, there are some sports drinks out there that I think have way too much potassium in them, just another reminder to take note of what you are consuming. You put way too much time and effort into conditioning your body for competition to have your chosen sports nutrition product let you down.

Having worked with so many athletes over the years working on the very things that slow them down, through trial and error I have gathered a lot of information on how to eliminate stomach problems, solve muscle cramping and fatigue management. It’s detailed in my book Sweat. Think. Go Faster which you can get here >>

Plan, prepare and execute because come race day you can’t outrun the past