Tips For Effective Runner Hydration

blue labeled plastic bottle

Photo by Oleg Magni on

I usually don’t drink much water before or during a workout. During races, however, I hit the fluids at almost every aid station in almost every race.

Over time, I figured out the right balance of consuming water/fluid against your training. For most, getting it 80% right or better is really as simple as carrying a small water bottle with you, or running near ready access to water.

I think most runners over-think and over-do hydration. I think spending more than a sentence discussing hyponatremia is overkill (if you drink the electrolyte fluid available, you aren’t drinking a gallon of water per hour, and you eat a salty diet before the race, you’re fine). And I think a lot of the discussion online and in running groups is simply about upselling ‘hydration’ products you mostly don’t need.

And a lot of hydration related distress is beyond the control of your hydration: You either went too hard, it’s too hot outside, or both. No amount of hydration can prevent that scenario, and the best that effective hydration can do is partially mitigate the problem. What many think is a hydration problem is really a climate adjustment problem.

Still, I’ve figured out some effective principles that can keep you hydrated without sending you on needless trips to the restroom.

Focus more on how you hydrate the day before key workouts and races.

If you’re dehydrated at 4pm, no amount of water is going to avoid you being somewhat affected from that dehydration in a 5pm workout. The body needs time to circulate that water and restore your organs/cells plus reverse side effects from dehydration. The closer to a workout or race you are dehydrated, the less likely you can drink your way out of the problem.

Ironically, the worst thing you can do to re-hydrate is to pound a lot of fluid right before your race or workout. All you’ll end up doing is peeing a lot before the run, and most likely needing to pee during the run. And you’ll still start the run rather close to the state you were in before you began binging on water.

Similar to how nutrition and recovery works, effective hydration is much more about your body of work in the preceding days than about what you did right before go-time. Balanced, consistent hydration in the day before you run will ensure you’re not dehydrated when it’s time to go.

If you know you’re got an important workout or a race, spend the prior couple days consistently sipping water. No need to chug: Carry a water bottle, or fill a cup and gradually empty it over time, depending on your circumstances. Get your 8 or so daily cups in the day before. If your run is later in the day, continue your consistent water intake during the morning and afternoon.

Unless running in the morning, take it easy on drinking water within 1-2 hours of your workout

Again, you don’t want to spend your run thinking about the restroom, or spend a lot of time before the run in the restroom.

One key reason you drink consistently the day before is so you can ease off the liquids in the hour or two before your run. So, if your water intake sends you to the restroom a lot, this gives your bladder a break and a chance to stay empty for the start of the run.

Obviously, if you run right after waking up, this would be a problem since we wake up somewhat dehydrated. So, provided you use the bathroom first thing, it’s no big deal having a cup or glass of water first thing in the morning right before running.

Keep it to one cup (8-10oz) before longer runs, as more than that may send you to the can in the first hour. If you need more than that, bring a water bottle with you and sip during the run. Your body will use it instead of peeing it out.

Avoid salty food right before hot or hard workouts.

Sodium leads the body to retain water. While this and other effects have some benefits, this can interfere with your body’s utilization of water for cooling/sweat. This can be a problem on warmer runs when you need that effect to cool off.

If you eat before your run, avoid processed foods (which are high in sodium) and take it easy on any other kinds of salty foods. It’s no big deal to eat something like a croissant, provided you’ve hydrated well beforehand. I’d be more worried about fast food, packaged box meals, snack food like potato chips, or pizza. You generally shouldn’t be eating that kind of food anyway, but definitely not before a hard run.

The sodium content will lead to any consumed water being retained, plus it may siphon any current hydration into buffering the inflamed tissue that results when you eat that stuff. This becomes a huge problem if it’s hot and/or humid outside during your run.

The shorter and less intense the workout, or the cooler it is outside, the less of a big deal this is. Of course, some people don’t run well with food in their stomach anyway. This should be easy for you then, since you probably won’t eat before running.

Salty electrolyte solutions like Gatorade are a judgment call. Generally, I’d only sip or drink it before a run if I would need to drink it during that run (such as during a marathon or a hard workout), and definitely only if the run is going to be long or otherwise difficult.

Unless running in the AM, drink a maximum of one cup of water right before heading out

Even though I said avoid water in the 1-2 hours before a run, it’s often a good idea to have a little bit of water right before heading out.

This not only mitigates any possible dehydrative effects from the prior 1-2 hours without fluid (not to mention can salve any pre-run paranoid cravings for water; some people do get them!), but it also provides a head start on restoring hydration from the run.

The water won’t digest until you’re some ways into the run, allowing that water to be effectively utilized.

But keep it to one cup (8oz) of water max. Any more than that, I find, leads to craving something else: A trip to the restroom within a few minutes of starting the run.

Aid stations do this for more practical reasons (like runners needing to be able to carry it), but they’ve got a point in giving you 4-8oz cups of fluid at those stations. About 4oz (half a cup, or four gulps) is probably an ideal amount of water to pound right before heading out.

The cleaner you eat, the more sodium you need to take in before/during workouts

Companies make money selling you salt tablets and non-nutritive electrolyte drinks (e.g. Nuun). They’ve sold runners on the risk of hyponatremia, where you take in so much fluid that there isn’t enough electrolytes in your body to compensate.

Generally speaking, a lot of runners who suffer this also eat incredibly clean diets. While the rich whole foods are quite good for you, they also lack sodium unless you add salt. Many of these people also don’t get enough sodium in their diet. Whether or not they do, add in a lot of hard running, with a lot of water intake, and now they’re in trouble. These people, barring an adjustment to their diets, probably do need electrolyte products.

Most of us are probably okay without salt tablets and Nuun. The irony of a low-calorie electrolyte drink is that an electrolyte drink’s key value in a race or hard run is its fast acting carbohydrate content. The sugar! The run is the one time you could really use sugar. Once they remove the sugar, they’ve removed virtually all of its value. You can get electrolytes from so many other sources before and during a run.

All of this is to say that, if you eat super clean, you should probably take in some extra sodium between your workouts. It’s okay to put some salt on your food! Any possible hyponatremic risk from hard running likely disappears if you get a bit more sodium in your diet. No salt tabs required!

Carry 16-20oz of water on longer runs. Take a sip or two every mile.

Most of the time, I don’t run with any water. Even in Chicago where the parks have water fountains, I usually didn’t have a need for them.

If I finished a run within an hour, I could get away with no hydration before the end of the run. Once I got into harder running like speedwork, or runs beyond 60-90 minutes, then it made sense for me to carry some fluid in a hand-held bottle. I often carried a hydration pack on 2-3+ hour long runs, and in the Vancouver Marathon.

You know what your limits are, and whether or not a run’s long enough for you to need water during the run. If so, get a portable water bottle of some kind and carry it, whether it’s hand-held or attached to a belt or a 2-liter hydration backpack. If in doubt, just bring a water bottle anyway: Worst case scenario, you don’t need it.

If you do bring water, play it safe and take a sip or two every so often, whether it’s every mile or two or every 10-15 minutes. Up to you, as long as you take sips on some intermittent schedule of brief intervals. This prevents the risk of waiting too long to hit the water bottle, of only drinking once you’ve began to unduly dehydrate. You stay ahead of your body’s schedule and maximize your performance.


Here I am running the Burrard Bridge at the 2019 Vancouver Marathon, wearing a 2L hydration pack.

Consider using a hydration vest for runs longer than 2 hours

I mentioned using my hydration vest in longer runs. This not only has the huge benefit of allowing me to easily carry more than the 16-20 oz of water that can fit in my hand, but allows me to easily carry other items like snacks, my wallet keys and phone, etc. Usually, I carry those items in a runner’s fannypack, and that has its limits. With all the weight on your back, it balances out more easily and is easier to run with, plus keeps your hands free.

Some marathons will also allow you to use a hydration pack (for example, Vancouver did, but the Chicago Marathon does not). This allows you to carry your choice of food and electrolyte fluid rather than relying on what the course makes available at aid stations.

Good packs aren’t cheap. In fact, I’d recommend getting the cheapest 2-3 liter hydration pack available (they often run $25-35), then separately buying a quality 2-3 liter leakproof bladder for about $20-30. The bladders that come with the original bag itself tend to be poor in quality, usually with a leaky hose assembly.

If you can afford this, hydration packs are super beneficial on your longest runs. I rarely ran out of fluid on long runs when I had one. A lot of people’s fatigue in the last hour of a long run comes from overall dehydration more than bonking or physical fatigue. Consistent sipping on water during the entire run can keep you going at the level you want to perform in the final hour.

For what should be a simple topic, hydration can be confounding for a lot of people. Often, it’s as simple as working ahead on your hydration with good consistent dietary and nutrition habits. From there, carrying some water with you when needed is probably all the worry you need.

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3 thoughts on “Tips For Effective Runner Hydration

  1. Yap Wai Meng says:

    Very useful information indeed! I happen to take salt capsules during half marathons, so maybe I will consider varying my diet a little to have more sodium in it.

  2. […] Hydrate well (40-80 oz/day) in the week leading up to the race. One glass of water before bed the night before […]

  3. swosei12blog says:

    Great info. Since I sweat a lot, I usually take a sip or two every 1/2 of a mile during long summer runs.

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