The Wall Street Journal Says You’re Drinking Too Much During Exercise. Are they right?


There are a few article topics that pop back up into mainstream media every year or two, like “too much exercise will kill you” and “you shouldn’t eat carbohydrates during exercise”. The “you’re drinking too much during exercise” chestnut made it into The Wall Street Journal. There’s plenty of great information in the article, but as with so many of these articles it’s important to figure out how the information applies to you.

The gist of the article (and I encourage you to read it first-hand) is that the long-held guidelines regarding hydration – consume enough fluids to prevent bodyweight loss greater than 3% during activity – are outdated because new research shows that athletes don’t experience a drop in performance when they lose that much bodyweight – and more – during exercise. The aim is to move athletes away from drinking on a schedule to drinking based on sensations of thirst. And they raise the specter of hyponatremia to drive home the point that overconsumption could kill you.

I have no disputes with the science presented in the WSJ piece, but even with the addition of some new studies we’ve seen this information and these recommendations before. In fact there was a piece by Alex Hutchinson (Sweat Science) from 2013 that covered the science and debate quite well. My issue – then, now, and the next time this comes up – is that there’s no one-size-fits-all solution for hydration. Here are some perspectives to take into consideration when thinking about if and how the WSJ article applies to you:

Elite athletes take risks to win races

Some of the examples cited in the article include the fact that Dean Karnazes runs cool-weather marathons without drinking, that Meb Keflezighi (winner of the Boston Marathon) loses 3-4% of his bodyweight and still wins, and that faster marathon finishers lose more bodyweight during races than slower marathon runners. The inference is that if the top performers can lose more weight than the long-standing guidelines and still perform and win, then you can too. But part of what makes an elite athlete an elite athlete is the ability to psychologically and physically endure more than average athletes can and certainly more than novices are prepared to. Years of practice and trial and error have taught them how to gauge their intensity and manage their fluid intake. They also know that losing too much fluid weight and overheating could destroy their performance, but they push that limit as far as they can in order to win. It’s the old “In order to win you have to risk losing” mantra. But it’s not wise to extend that expectation to middle-of-the-pack or back-of-the-pack marathoners, triathletes, and cyclists.

It’s not the weight, it’s the heat

So, why does it matter how much water you lose during exercise? It matters because the fluid in your body is what gets pushed out onto the skin as sweat to evaporate and help you manage core temperature. The higher your workload (faster pace), the more heat you generate. When core temperature rises, motivation to continue at a high workload diminishes, even before there is a physical response to reduce workload. A cool environment, water poured on the athlete, or ice packs can reduce the reliance on sweat for this cooling. This can enable an athlete to blunt the increase of core temperature despite a significant loss in total body fluid weight.

In the Sweat Science article referenced above Alex Hutchinson cites a study that didn’t show a change in performance or a big increase in rectal temperature during a cycling time trial in 33C (91.4 degrees Fahrenheit) heat when subjects were 0%, 2%, or 3% dehydrated. But the time trials were only 25km (approx. 15miles) and the athletes were continually infused with fluids to maintain their level of dehydration. In the real world the issue of controlling core temperature is complicated by the fact that events are often much longer than 15 miles, environmental conditions change (it gets hotter or colder during the event), and athletes have to remember to replenish fluids and have them available.

Losing water weight makes you lighter, and being lighter improves performance.

The statement above is paraphrased from the WSJ article, and it’s correct. Talking to Jason Koop, my top ultrarunning coach, he tells his athletes that the percentage weight loss is about equal to the performance gain. Basically, once you lose 2% of your bodyweight during a run you can sustain a pace that’s 2% faster. The impact is likely greater for runners than cyclists, though, because runners have to lift their bodyweight with every stride.

The problem is, there’s a balance point involved here. Up to a point, losing some water weight might be advantageous because your power to weight ratio will go up. But then the core temperature problem catches up to you and power/pace drops, eliminating the advantage. And what’s worse, getting an athlete back to optimal function after they’ve tipped over that edge isn’t quick. If you have already optimized everything else and you’re still looking for that edge that might get you a PR or a win, then mild dehydration for weight loss–in racing but not training–might be an option. But for most athletes there are a lot of other steps that can improve race-day performance before needing to accept the risks involved in this strategy.

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The human body has no water gauge

So, let’s assume that slight dehydration is actually good for performance but that overheating and excessive fluid loss is bad for performance. In the middle of a race how are you going to determine your hydration status? A scale? Pee sticks? Rectal thermometer? When it comes to workload we can measure power output and pace, but the body has no water gauge. Tim Noakes says to use the sensation of thirst. I think the sensation of thirst is useful, but it is just one factor in determining how much fluid to consume and when. There are a lot of variables to consider: ambient temperature and humidity, changing temperatures during the day, the duration of the event, athlete’s intensity level, the availability of fluids, the athlete’s ability to carry fluids, etc. Is your sensation of thirst so attuned you can account for all these variables? And perhaps the bigger issue is whether an athlete will actually respond to the sensation of thirst! Athletes get tired. They get fixated on holding a wheel or staying at a certain pace. They forget to drink; they forget they’re thirsty. Sometimes they just don’t care that they’re thirsty or they remember they’re thirsty when there’s no water available.

A hydration strategy or schedule is not about pounding fluids or drinking despite signs you don’t need to. It’s about making sure athletes are engaged enough to make the decision to drink or not to drink, and to make sure they have fluids available when they need them. Availability is less of a problem in road marathons where you’re never more than a mile from water. But it’s huge consideration in ultramarathons, road cycling and MTB events, and Ironman triathlons (at least the cycling leg).

If you take away nothing else…

Hydration is extremely individual and the best thing you can do is start with a strategy or schedule and adjust as needed based on the environment, your intensity, your sweat rate, and what your body is telling you. On the grand scale of hydration guidance, you can think of purposeful dehydration for improved performance and the risk of hyponatremia as the opposite ends of the spectrum, and there’s a huge range of options between these extremes. Over the years I have gathered a pretty good sense for the audience this blog reaches. On average you are a group of reasonably experienced and educated athletes who train consistently and compete or participate in several events each year. If that description describes you, then there is plenty of room between those extremes to find what works best for you. Your risks of hyponatremia are remote and there are better ways to improve your performance than purposely dehydrating yourself during your next race.

Have a Great Weekend,
Chris Carmichael
CEO/Head Coach of CTS

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Comments 19

  1. Is there a difference between hydrating with water vs hydrating with fluid with electrolytes?
    My understanding of the physiology is that plain water goes primarily to the Intracellular spaces and can led to more rapid hyponatremia, while fluids with electrolytes will replenish plasma and extracellular levels 2/3 and intracellular spaces 1/3, thereby maintaining plasma fluid levels without the associated risk of hyponatremia.
    Is anyone able to confirm this, or explain how/if my understanding of this is wrong?

  2. I find that hydration is dependent on the temperature of the moment. I can ride a trail in the spring with less hydration than on a hot summer day. I also have found that hydration is not just about water but electrolyte replacement. I use tea (unsweetened) and coconut juice (with pulp) to help with my hydration regimen on long rides.

  3. 35 years ago, Jack Skaff, the doctor/coach who directed the Honolulu Marathon Clinic, preached “10 ounces every 20 minutes” during sustained running or cycling activity. I’ve never gone wrong following his advice.

  4. I think you must make a distinction between training and racing. On race days I always believed that for distance events – especially on hot days – you had to rehydrate early and in the later stages of the race you gutted it out without taking on fluids.

    However, training is different. It can take days for the body to recover from dehydration at the cellular level. So when training you must keep your hydration up by continually drinking.

  5. Great comments! As an ultra trail runner and former triathlete its about what works for you! Lots of trial and error. This is not something to play with in competition or where you lack control. Become your own expert. Don’t rely on others!

  6. Hi all,
    Well, it’s my understanding not all sodium is “created” equal. Table salt has been refined, (w/ chemicals), where some other salts, like Himalayan & certain sea salts), have a lot more healthful minerals.
    I climb, (on foot) 8k in 4.5 to 5 hr. on the average, and can go through 140 oz. never taking a pee until an hour after, at times. I live in the desert, can ride in 110F (as long as I keep moving), but find it’s helpful to have some of my liquids as electrolytes.
    So, as the articles have eluded to, hydrating has some variables indeed, (as Chris mentioned), not the least being the type of liquid, (& of course, most electrolyte co’s have done lots of research to boost their products use).

    I sweat like crazy, (CTS has talked about how many trained folks sweat sooner), so I make sure I always have a Camelbak-type hose to drink from, even on my bike whens it’s warm), as I know I stay more hydrated with this easy delivery system.

    Too bad someone wasn’t at the finish of Stage 2 of the Amgen Tour of Calif. to take blood or urine samples for dehydration studies, where the pros had to ride in 110F for some of the stage, and finish with a 2k ft. climb in 3.7 miles. These guys, (very few who were able to train in the heat before the event), were collapsing at the finish.
    I’ve also read, (I think here at CTS), that dehydration can effect oxygen uptake?
    Be well!

    1. Trace minerals affect the flavor of salt, not the chemical structure of the sodium. There is the issue that chloride can contribute to high blood pressure in sensitive people, so people with “salt-sensitive” hypertension are better off replacing sodium with sodium carbonates (which are the main ingredient of electrolyte tablets anyway) than with sodium chloride.

      1. Thanks for that clarification Dana, and explanation of these 2 types of sodium. I still use a “holistic-type” salt over processed “table salt”, since some of the other trace minerals must do some good.
        I’ve heard that potassium helps to balance the “muscle action”, similar to sodium, but in an opposite way, (contraction v relaxing)?

  7. We all have our personal opinions and experiences. The first dozen of 35 marathons I ran had only water on the course, some no more than a few water stations. I repeatedly broke 3 hours, ran Boston and am still around (at 71) to remember those experiences. More recently I did an Olympic distance triathlon and barely had 10 ounces of well balance electrolyte drink (NOT store bought fluid, personally mixed) and crashed in the first mile of the run!

    Up until about 10 years ago race medical personnel typically treated only for dehydration at the end of a marathon. The death at Boston from hyponatremia made everyone aware of the dangers of extremely low sodium levels, and the danger of using a saline fluid with a sodium content lower than normal blood levels.

    All those facts are blurred in the WSJ article. And as everyone here and the comments on the WSJ exhibit, we all are slight variations of what is typically recommended. While I have great respect for Noakes and his research, I keep in mind that his books are written for a non-scientific audience. And, his research has not provided a “one rule fits all” answer.

    As with other physiological responses, there is a great amount of variance. And designing and conducting a peer reviewed, double blind study that controls all the variables that effect it’s outcome, at this stage of our knowledge, is impossible. That’s why the scientific approach is a journey, and the “answers” we have one day usually are at least modified as the research continues.

    The interpretation of results – scientific and personal – need to be taken only as a suggested approach. We all need to continue our personal experimentation to find what works best for us. The amount of fluid, the sodium concentration, the additional minerals, the frequency of consumptions, the amount of consumption each time, the starting point of our bodies, the effort – both what we put into the activity and what the environment presents to be overcome, the emotional stress, the level of rest, our genetic make-up and on .. all contribute to our response.

    I tell all my athletes to experiment well before their goal race. Adjust, modify, and completely change the approach to hydration, electrolyte and fuel consumption.

    Pretty long winded, I know! My take-away is go into a performance – training or racing – prepared, well fueled and well hydrated, and well rested and trained. The misleading word there is “well.” I believe what makes endurance sports and endurance athletes such a challenge is our enormous challenge and our individualism. The research can only provide us with a starting point, and suggestions. We’ve all been there. What worked perfectly one day, will be a disaster on another day. Even under the same circumstances.

    Be careful out there, have fun and swim like a dolphin, ride like you stole it and run like they’re chasing you! Oh, and never, never, never stop.

  8. As for the idea that “no one dies from dehydration during an event,” no, not directly during a marathon or shorter race, but people do die or suffer brain injury from heat stress caused by dehydration, and they do so a lot more often than they’re injured by hyponatremia. Further, chronic subclinical dehydration caused by inadequate sodium intake can derail training and/or recovery, and easily progress to clinical dehydration. Been there, done that, got the IV. There’s plenty of current research – ignored by this article – showing that average sodium intake is perfectly safe for average people, and yet even athletes who need high sodium intake are told to take less and less sodium.

  9. I’m just so tired of the idea that replacing fluids causes hyponatremia. Maybe in 6-hour marathoners who’ve been told to take plain water at every stop, but for most of us, inadequate sodium intake causes inadequate serum sodium, which in turn causes or exacerbates DEhydration. Replace lost fluids – AND replace lost minerals. Talking about the timing is important, just as we talk about the timing of calories and protein. The idea that we should just not replace fluids ought to be a no-brainer.

  10. This topic will continue to flip flop to the end of time…. Personally I believe hydration has a lot to due with lifestyle and conditioning. My opinion (and experience) is, if you went out the night before and consumed a few alcoholic beverages, you’ll definitely suffer more from dehydration the next day. If your diet is high in sodium, you might retain more water and expel more the next day during physical activity.

    One thing I think we can all agree on is that hydration is important and starts before the day of the event. It’s part of your lifestyle. What you eat and drink today will effect what you do tomorrow…

    Hydration is a science and requires research. Research requires grants. Grants require funding. Funding requires donations and sponsors. Sometimes you need to research the research or you’ll drive your self crazy. You’ll turn your body into a chemistry set.
    Your body will tell you what it needs but when your thirsty you’re probably a little dehydrated…

  11. I saw no link to the WSJ article. I think it is

    Everyone should read Tim Noakes “Waterlogged” book, not just for hydration, but a lot of ways the body elegantly handles physical stress. Also realize that a lot of the “standards” come from the Gatorade Sports Science Institute and are biased toward, you guessed it, selling Gatorade. People do die from overhydration in sport events. Performance may suffer, but nobody dies from dehydration in those events. You have to be sensible and think about hydration just as much as other aspects of race strategy. Some a priori schedule does not release you from that responsibility as external and physiological conditions are not predictable and, even if they were, we don’t really know enough to predict what is best.

  12. I’m a strong recreational rider. I don’t race. But I ride 10 -30 mile rides several times a week in all kinds of weather. I always carry at least 2 water bottles. I drink water only, except on very hot days I’ll use diluted sports drink. I only bonked once in my entire 15 years of riding, that on a 98 deg day with a camelback full of water, and I couldn’t suck it out fast enough to hydrate. In less than an hour I got dropped. It taught me some things. Now I drink a few gulps every 15 min or so. It works for me, and I ride my max effort almost always.

  13. I have a female friend who sweats very little. She can do Moab for the day on 70oz, comes back looking a tad dusty. I have a nice glisten standing around at 9° humidity on the same day, need the whole 100oz and a collapsible 16oz bag stuffed in the pack, come back with everything i have on sweat stained, looking like a dishrag. Just once, I’d like to see an “author” of one of these article declare they have actually taken a statistics class at some point in their education. And that they they understand data manipulation.

  14. As Chris points out, hydration (and caloric, electrolyte) needs can vary greatly between individuals and conditions present. Over the years I’ve found I can get away with small amounts of each in shorter races. As the distance or heat/humidity increases the more important these all become in sustaining performance. Bottom line is you have to experiment (hopefully in training, but sometimes you have to learn the hard way in races) to figure out what works for you in a variety of situations. Take in advice you read or get from friends, but in the end you and/or your coach will have to find the right mix for you. You’ll know what’s not working in short order, especially when it gets hot!

  15. Hi All
    I cycle every Saturday at 6.30 am in Melbourne Australia with a group of 20 to 60 riders for 55km at a good strong pace throughout and only use one 500ml bottle with a electrolyte solution. THIS IS PLENTY FOR THAT DISTANCE. I have found with years of cycling the body can work at a high level on small amounts of nutrition.
    Only if the weather is hot I take two 500ml bottles.

    1. Try doing that in Cairns in summer! I think what he is getting to is there are many variables and we need to know our bodies, or train by feel.

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