Shorts: Hydrating for Running

Hydration can be crucial to happiness. But all things should be taken in moderation.

Seated at my computer in the ICU, I chuckled out loud while reading an interview with Kilian Jornet and Emilie Forsberg. When the nurse next to me asked what was so funny, I explained that this famous endurance couple clearly dealt with the same controversy as do Taylor and I: do you need to bring food and water with you to run or ski, and if so, how much? Kilian and I are on the same page: likely not, and if so, not much.  Emelie (and Taylor) say:

“He doesn’t like to eat when he is out! I take some food with me when I am out longer, like eight hours. And sometimes I wish that Kilian had some. I have been telling him that why can’t he have some chocolate in his backpack for me. Just in case. But it has not happened so far. So, I often take my own.”

Today I want to briefly address hydration for running, and my thoughts on the matter are governed by two observations. First, most people begin their workout dehydrated. Second, most people drink far too much during exercise.  I’ll add the caveat that you have to figure out what works for you, and you should be safe about it, but that said, here are some thoughts to chew on and a plan to be more effective with your hydration. 

You’re Dehydrated Right Now, Drink Something.

If you’re concerned about athletic performance and speedy recovery, the majority of your attention should be focused on preparation for and recovery from your workouts. Thirst is a poor indication of hydration status, and most of us are walking around in a state of mild dehydration throughout the day. That 22 hours of mild to moderate dehydration is much more significant for your performance than whether you spend a few hours of effort mildly dehydrated.

Drink water throughout the day, with food (see below). When you finish a long workout (>1-1.5 hrs), replenish nutrition and hydration promptly. For most athletes, this will look like a 1-pint commercially available recovery drink of 1 part protein to 3 parts carbohydrates within 30 minutes of finishing exercise, followed by a real meal within 1-2 hours.

You’re Afraid of Discomfort, Give It A Try.

How many runners do you see running around cities and parks carrying a water bottle in hand or wearing a camelback? Why would someone choose to carry weight in a water-rich environment, especially given that the majority of runners don’t run for more than an hour at a time?

I think that it’s a safety blanket. I carry my bottle and I’m no longer scared that I might at some point be thirsty. Sure, my bicep aches and I run a bit wonky because I’m off balance, but I won’t be thirsty. Ever. (Also, I look like a super cool ultra runner, running my 6-mile loop with a vest and bottles). 

The problem is, if you’re never thirsty, you don’t know how that works for you. You don’t know what is the mild discomfort of drying out your mouth by breathing hard and what is the lead-blanket full-body heaviness that comes from real dehydration. And you don’t ever give yourself the chance to go without and potentially discover that hey, this works just fine.

Pointless bottle carrying is a scourge. Simplify.

Weight Decreases Performance Now, Dehydration Later.

The common figure used as a scare tactic is that you only need to be 2% dehydrated to see a decrease in performance. If we round up my weight to 160 lbs, that means that I can lose 3.3 lbs of water weight ( 1.5 L) before I see a downside. How quickly I lose that water will depend on the climate. Running here in Portland in 100% humidity and cool temperatures, this could take several hours. In the heat and at altitude, losses will be faster.

In contrast, the moment that you load yourself down with water, you see a performance decrease. Weight adds up over miles, which is why we go to such lengths to have light shoes and to carry as little as possible on long runs. Why do you focus so much effort on minimizing your gear and then carry two liters of water? Water is usually the single heaviest thing in a runner’s pack.

Barring extreme conditions, if you’re not racing or trying to produce a peak performance effort, it’s reasonable to run for 2-3 hours without supplemental water. You will finish your run dehydrated by a few pounds. You will need to replenish that. But in return, your pack will be lighter and your day simplified.

To Drink, Eat. To Eat, Drink.

Don’t drink just-water. You’re not made of just-water, so if you drink just-water without salt, sugar, electrolytes, then you’re essentially diluting yourself. Your kidneys are smart, and they won’t put up with that, so you’ll just pee out that extra water. That means that it’s largely wasted, but because the kidneys aren’t perfectly efficient, you’ll also be penalized by peeing out salt. This is how hyponatremia happens. If your pee is clear, you’re over-hydrating.

If you want to consume liquids, they either should be part of a mix with sugar and electrolytes, or you should eat simultaneously. Likewise, the amount of food that leaves the stomach into the amusingly names duodenum (do-ah-den-um) is determined in large part by the mix of food and water in the stomach. To grossly oversimplify, if the mix is too thick or too thin, then so-called gastric emptying is slowed and you get to run around with that sloshy feeling. This is not lost on makers of gels– if you follow the direction on the back of a packet of Gu and consume it with a couple gulps of water, you’ll make a solution in the stomach that is ideal for gastric emptying.

Rant Over. Here’s A Plan.

Ok. So. You’re dehydrated before you start. You carry unnecessary water because you’re afraid of what thirsty is like and you want to look like a runner. The weight of the water slows you down and throws off your stride. You drink plain water without food and make things worse. This is bad.

Here’s a better idea.

1. As an athlete, you should drink fluids throughout the day. More than you think that you need based on thirst. It’s best to take it with some kind of food, but since we’re not exercising, plain water is fine. Just don’t be shy with the salt at dinner.

2. In standard conditions (temps <75 f., moderate to high humidity), experiment with not carrying water on runs of less than 1.5 hours. Most athletes will adapt and find that they can go somewhere between 2-3 hours without carrying a bottle. If temps are hotter or humidity significantly lower, these times are shorter. Discover for yourself by experimenting during training, before races or long runs.

3. If you have a run of adequate length to need water, then avoid carrying it if possible. Drink from an intermediate source, like a river/stream/water fountain/7-11.

4. If sources aren’t available and you need to carry water, carry as little as possible. On long mountain runs, I will usually carry 20 oz of water across any trail section where I think there won’t be water for between 1-1.5 hrs or about 6-10 miles.

5. For maximum effectiveness, consume that water with a small amount of sugar and salt.

6. When you finish your run, drink a recovery drink within 30 minutes, and then eat a real meal. For bonus points, weigh yourself before and after and replenish fluids by weight.

This isn’t too complicated once you get past the collective fear of dehydration and an entire sports beverage industry that tries to persuade everyone hitting the elliptical machine after work that they need blue-drink. Let me know what works for you, or if you think I’m crazy.

The one thing that I know is that it really works for me.

Category: Knowledge & TechniqueRunning


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