Getting his sweat tested helped this Arizonan age-grouper complete his first Ironman cramp-free!

By Dave Colley | 3 Minute Read

My ears perked up when I first heard about Precision Hydration's Sweat Tests. My first thought was "I need to offer my clients this test"! I’m a Sports Dietitian in Arizona and my clients are endurance athletes - triathletes, ultra-runners, and distance cyclists.

You probably know that it’s hot in Arizona. Blazing hot. People sweat a ton, and with the sweat losses go the electrolyte (mostly sodium). As regular readers of the PH blog will know, sodium has many essential functions in the body, including maintaining fluid balance, cognitive function, nerve impulse transmission, absorption of nutrients in the gut and muscle contraction. It's crucial to maintaining your performance.

The Advanced Sweat Test measures your 'sweat sodium concentration' - the amount of sodium you lose per litre (32oz) of sweat, which is largely determined by genetics. This measure is highly variable from person to person. You can be a heavy sweater, but not lose much sodium. You can be a heavy sweater and lose a lot of sodium. You can be a light sweater and lose a little or a lot of sodium.


I’ve been doing the testing for nearly 2 years now and the results have been incredible. Athletes who have previously had to deal with severe, systemic cramping have been able to complete endurance events with no cramps at all when following the hydration/electrolyte replacement plan we implement after their test!

But this type of athlete only makes up a small percentage of the people who come to me for sweat testing. You see, cramping isn’t the only issue that can occur if you don’t hydrate properly, it’s just the most obvious one. Many people who aren’t consuming enough salt during training/racing feel fatigued, aren’t performing up to their potential, and aren’t recovering well. These symptoms may be attributed to other variables – your fuel plan is off, your training plan is too heavy, you're not getting enough rest, etc  and then it all clicks into place when they learn how to hydrate appropriately for them! 

Enter Jeremy Besse

Jeremy Besse started up with me in May 2016. He had a 70.3 on the calendar and was looking to race Ironman Arizona in 2017. We set to work on his fuel plan and I encouraged him to take the Sweat Test as he had complained of major cramping during rides and runs. We had to get these issues worked out if Ironman was going to be a possibility.


Jeremy Besse had issues with cramp before his sweat test

Sure enough, when I tested Jeremy, his sweat sodium concentration was off the charts! He loses A LOT of salt per litre of sweat. He can attest to my level of excitement with these findings (sorry, Jeremy!) as I knew this would be a true assessment of the test’s efficacy in determining sodium replenishment needs.

His needs were ~1,500mg of sodium per 32 oz. of fluid. I started him on the Precision Hydration 1500 strength electrolyte drink mixes – 1.5 packets per 22-ounce bottle of fluid. Jeremy used this protocol for all of his long rides/runs throughout Ironman training and encountered no cramping issues. The icing on the cake, he recently completed Ironman Arizona with no cramping problems whatsoever over the course of the long, hot day. This is a true testament to the efficacy of the test, when considering his extremely high sweat sodium concentration and previous issues with cramping. 

“Knowing what is going on under your hood is more important than any other portion of the race preparation and execution. Simply drinking water or sports drink without knowing what your body really needs is like pumping up your tires without a gauge. Combined with the vital Sweat Test, the preparation plan Brooke has laid out for me was ironclad and proved to be spot on for Ironman Oceanside 70.3, Mountain Man Half Iron and Ironman Arizona.” – Jeremy Besse



I have countless other success stories, from athletes of all levels and abilities. This test is an absolutely necessity for anyone taking their racing seriously (in my humble opinion!). It allows athletes to gain knowledge about their individual sweat losses, and to develop an effective plan instead of simply guessing. I Sweat Test all year round, anytime is a good time to get tested. So be one step ahead of your competition, and get your test on the calendar. You won’t be disappointed.

Brooke Schohl, MS, RD, CSSD is a registered sports dietitian and the owner of Fuel to the Finish Endurance Nutrition Coaching in Scottsdale, Arizona. She is an avid triathlete, having completed many triathlons of all distances including 3 Ironman races. She integrates that personal experience and knowledge into developing customised, sport-specific fuelling plans for her clients as well as sweat sodium concentration testing. For more information on services and offerings, visit her website at

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