How Much Fluid Should I Drink?

By T.J. Murphy

Answering the timeless triathlon question: How much fluid should I drink?

In the days leading up to the Ironman World Championship, a range of symposiums and Q & A sessions are held. One way or another, the discussions always seem to get snagged on one question. Someone always asks, "How much should I drink during the race?" It's so hard to qualify for the Ironman these days, the standard so high, it seems highly illogical that hydration remains so puzzling to so many veterans in triathlon.

On second thought, maybe it's extremely logical. If you look back through the decades to the 1950s, to the running boom of the 1970s and the triathlon boom of the 1980s, along with those booms the rise of Gatorade from a concoction designed to help college football players confront the smothering intermix of heat and humidity in Florida (not unlike Kona on a cloudless day) to the $7-billion-per year sports drink business of today, there's been a lot of information, coaching advice, anecdotal experience, research and counter-research that is hellishly confusing.

Hydration History

In the 1950s, drinking water was for the weak. My dad played football for a legendary high school coach named Les Hipple, profiled in the book, A Coach's Life, by Dan Kellams. "Playing a sport for Coach Les Hipple meant a life of rigor, clean living, modest behavior, and self-denial"--and part of that self-denial was that athletes weren't allowed to drink water during tough practices in sweltering 90-degree weather. My dad, Pat Murphy, would in later years become a top-ranked masters runner and marathoner. He told me that Hipple's rules against hydration had some of the athletes so overwrought they would hide lemon wedges in their football helmets.

In the 1960s, in a not uncommon episode in the pre-dawn of Gatorade, Don Kardong won the Boston Marathon without taking a sip of anything. The idea of an aid station was antithetical to running--the prevailing advice of the time was to not drink a thing. The term "aid station" had little (if any) meaning to runners. Sports science began to shift into gear in the 1970s, Ball State's David Costill paying for his first studies through Gatorade's financial support. Hydration became a thing. By 1981, the Comrades ultra-marathon in South Africa, working with a young sports scientist and runner who would go on to become one of the world's most accomplished researchers in the science of endurance athletics, Dr. Tim Noakes, placed aid stations at ever mile of the 56-mile race.

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I did my share of running races and triathlons in the 1980s and never really thought about how much I should drink or what I should drink. But in 1990, I did the Escape from Alcatraz back when the race director the the old-school David Horning. The run back then was 13 miles, most of it in the Golden Gate Headlands of Marin. There was exactly one aid station and he had to be convinced by a running store manager, Mike Fanelli, to even have that one. I was wobbly at the finish line--it had been a hot day--and a chiropractor/triathlete by the name of Peter Lewandowski pulled me by the arm to over to a table of cups and water and watched me drink three or four before he let me leave his sight.

A year or so after that, I raced the Wildflower long course event with a new mindset about hydration, guzzling every drop of Gatorade I could get my hands on during the race, wanting to increase performance and prevent heat illness. In later years, at races like Ironman Australia, I had gone too far for my stomach, drinking and eating in a way that gave me stomach aches that were hard to forget about.

By the mid-1990s, the American College of Sports Medicine had published guidelines that suggested you were basically being an idiot in a long race or triathlon if you weren't drinking fluids constantly, well before the thirst kicked in.

Dehydrated or Over-hydrated?

Triathlon imagery is always connected to issues of hydration. Some of the most infamous were from Hawaii: Julie Moss death-crawling across the finish line. Paula Newby-Fraser collapsing a quarter-mile away from the finish. Chris Legh's collapse and ambulance ride to the hospital for surgery.

The argument over the last 15 years has been about the mechanism of hyponatremia, the potentially-fatal state where sodium has been flushed out of the body. Noakes wrote one of his books, Waterlogged: The Serious Problem of Over-hydration in Endurance Sports, in response to the death of a runner at the Boston Marathon, who he reported was the victim of trying to drink according to the standards being promoted at the time, around 60 ounces per hour. For any serious triathlete wanting to know the history and "the science of hydration," the research culture behind it and the influence of industry, it's a must-read book.

I spoke with Noakes about the subject over a Skype call recently. Although he had pushed races like Comrades to add more aid stations in the early days, in the past decade he's been advising events like the London Marathon to revise their drinking guidelines and cut back on aid stations. "It's when the drink companies started over-promoting drinks that the risk of hyponatremia from over-drinking became a problem." He added that this was due to the suggestion, picked up on by and distributed by the ACSM, that athletes should drink as much as tolerable. This is when things got dangerous. "It was a death knell." Noakes told me that we humans are wired in such a way that the only real danger of not being able to drink enough fluids is that we'll have to slow down. The danger, he says, lies in aggressively trying drink fluids at rates the body can't keep up with--resulting in a hyponatremic state, from the form of excess fluids sloshing in the stomach to the most severe episodes of falling into a coma and risking death. In 2007, Noakes said with relief, the ACSM revised their guidelines to fit the "drink to thirst" approach to hydration.

High-Performance Triathlon & Hydration Strategy

Triathlon is tricky in that we are making demands of our bodies that are unnatural. Depending on your fitness, a 10k road race takes 30, 40 or more minutes. Even on a hot morning, you just aren't out there very long. A long triathlon is another deal. You're out there for hours. In a place like Kona, you're tired, it's hot, it's humid, sweat won't easily evaporate off of your skin. The sun just crushes you. The body sweats to dissipate heat, a system that requires tremendous energy in a hot, humid environment, yet you, the athlete, with eyes on the clock and those you might be racing, keep pressing down on the hammer.

The Hawaii Ironman is the super extreme--extreme efforts over an extreme distance in extreme conditions. Not to mention extreme competition. Hydration is a confusing topic because we're not running just a marathon or six mile race. Even the best are out there for eight hours. Hydration is as critical to performance just as energy management is critical. If you're planning on drinking to thirst, then one thing you know is that you're going to be thirsty. So what's the plan?

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This past May, I listened to a presentation by Asker Jeukendrup, PhD, a professor at the University of Birmingham and a consultant with the Gatorade Sports Science Institute. Jeukendrup had discussed the data supporting how if an athlete mixes up the type of carbohydrates they use during a race, they can increase how much carbohydrate they can oxidize per hour. The last time I had interviewed Jeukendrup, it was the day before he was racing in Kona. An accomplished scientist and editor of the European Journal of Sports Science, he's also an accomplished triathlete. So he gets it on several levels--he knows what it's like on the Queen K, and he can also talk to you about what metabolism looks like under an electron microscope. I asked him what sort of practical ideas he had for the confused Ironman triathlete.

"You have to have a plan going in," he told me. "But don't push it if it's not working. Be sensible. You have to be flexible in how you carry out that plan. If you're body is responding negatively, you have to listen and make adjustments." In other words, you come up with a plan for what worked for you in other races and in your long training. Maybe it's so many gels per hour, or so many ounces of fluid per hour, or so much nut butter if you're a low-carb athlete, etc, but if your stomach is sending you messages that it's too much, or you need more, or whatever, be willing to amend if not ditch the plan. It's also worth mentioning that one of the performance costs of drinking too much is how the clock keeps ticking when you stop at a porto-potty.

Also, you have a back-up plan if things go awry, Jeukendrup said. And as Ben Greenfield previously reported in LAVA, also have a back-up plan for the missing special needs bag.

In effect, you can prevent over-hydration by paying attention to whether your stomach is emptying. One of the problems introduced in the Ironman is that your brain is making the kind of demands that move the blood from the inner organs to the extremities. Plus the body has heat and humidity to deal with--a huge thief of resources. So as Jeukendrup explained it to me, if competing demands are tying your stomach in a knot, then slow down and let things settle. Ultimately, racing to your best potential is going to require a good plan, paying a lot of attention to how your body is responding to things, and being willing to make adjustments.

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About the Author

LAVA Magazine

Founded in 2010 and named after the iconic volcanic rock fields found at the Ironman World Championship in Hawaii, LAVA Magazine is the world's premier triathlon magazine. Along with the magazine's stunning photography and design, every issue is full of the newest gear debuts and reviews, training advice from the world's best coaches, and in-depth athlete profiles. Go to for up-to-the-minute training, racing and triathlon news, and follow them at @LavaMagazine.
Founded in 2010 and named after the iconic volcanic rock fields found at the Ironman World Championship in Hawaii, LAVA Magazine is the world's premier triathlon magazine. Along with the magazine's stunning photography and design, every issue is full of the newest gear debuts and reviews, training advice from the world's best coaches, and in-depth athlete profiles. Go to for up-to-the-minute training, racing and triathlon news, and follow them at @LavaMagazine.

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