Expert advice about optimizing hydration has changed significantly over the past few decades, so it’s no surprise that there are lingering myths about the topic. I had coaches in high school, for example, whose mantra was, “If you’re thirsty, you’re already dehydrated,” encouraging us to suck down as much H2O as possible in the days before a game. Others insist that thirst should ultimately guide water consumption. So what’s the correct strategy? How can you ensure you’re properly hydrated for a run? We’re giving you the low-down on how to wet your whistle before, during, and after your workouts.
Why does hydration matter?
Before we delve into recommendations, we’ll let you in on some not so secret intel about the importance of hydration. Drinking water regularly is an integral aspect of overall health and a critical component of any weight loss regimen. But water isn’t only important because it’s a health boon—there are serious dangers to both dehydration and overhydration.
According to a USA Track & Field Advisory (USATF) from the Director of Athletic Training of the University of Connecticut, dehydration occurs when fluid losses are greater than fluid intake—when you’re sweating or peeing out more than you are drinking. Dehydration can cause a slew of uncomfortable symptoms, from headaches to nausea, and can be fatal if untreated.
Because the risk of dehydration increases as sweat amps up (like during intense activity in warm conditions), it seems intuitive that guzzling water would be an effective way to ward off this potentially deadly condition. But that intuition (and the advice of my high school coaches) can be misleading, because it’s also possible to overhydrate. Hyponatremia, defined by low blood sodium, can be as scary as its name suggests. Your body needs a critical level of sodium to function, and drinking too much water increases the rate at which sodium leaves the body. Factor in that sodium is excreted through sweat, and you’ll see just how dangerous a combination like intense exercise and overhydration can be.
So because both over and under hydrating pose unique health risks, there’s a balance to be struck between the two. Thankfully, this balance isn’t too difficult to figure out, and Runkeeper is here to help you do so!
Before a run:
By the time you start your run, you should be on the upper end of properly hydrated. The American College of Sports Medicine (ACSM) recommends drinking 16-20 fluid ounces—that’s two to two and a half cups—of water or sports drink at least four hours prior to your run (check out this article from Runner’s World for some sports drink suggestions for longer runs).
What about immediately before you take off? ACSM says drinking 8-12 fluid ounces of water about 10-15 minutes before your run is your best bet for optimal pre-race hydration. If you’re looking to make your pre-run ritual particularly cool, try a syrupy slushy! Finally, if you’re unsure of whether you’re hydrated, urine color analysis is one of the most effective ways to check your hydration status.
During the run:
Here’s where things get a little tricky. While the ACSM recommends drinking 3-8 fluid ounces of water every 15-20 minutes for runs shorter than 60 minutes and of sports drinks for runs over an hour (to replenish your energy stores and electrolytes), the Clinical Journal of Sports Medicine published research last year that thirst is an adequate and legitimate indicator of hydration status.
What should we do about those conflicting recommendations? Alex Hutchinson of Runner’s World suggests the journal’s research doesn’t consider runs of longer distances and intensities, situations in which dangerous levels of dehydration can sneak up on you in ways they’d be less likely to during shorter workouts. So for longer runs and races, it’s probably a good idea to take those ACSM recommendations more seriously.
The Rock ‘n’ Roll races recommend, for example, that runners calculate hydration needs with their individual sweat rates in mind. Do so by weighing yourself in the buff before and after a trial hour run at race-speed, subtracting your body weight post run from your pre-run weight, converting the pounds lost to ounces, adding the volume of any fluids you drank during that run, and dividing that number by four (sounds complex, but we promise it’s a relatively simple and one-time calculation!). The number you come up with reflects your hydration needs every 15 minutes, which can be helpful to know for your longer runs. There’ll be hydration stations along the way of any established race, so keep an eye out when you’re on route, and make use of them! Just out to run a quick 5K? You’re probably fine simply listening for and responding to your body’s cues.
After the run:
USATF suggests that after light and heavy sweat sessions alike, your hydration goal should be to replace fluid losses within two hours. And although cracking open a well-deserved cold beer post-run may be one of the feelings runners live for, bear in mind that some liquids will better take care of your recovery needs than others. Be careful with alcohol, caffeine, and soft drinks after your run, which may taste refreshing, but are actually dehydrating.
If drinking large quantities of water isn’t your thing, try out some of these post-run drinks from active.com that do the triple duty of hydrating and replenishing carbohydrates and electrolyte stores.
To sum things up, hydration is serious business, but it shouldn’t be too complicated. Go into a run properly hydrated, but remember that there’s a balance to strike between drinking too much and too little. For longer runs and races you may want to do some pre-calibration to keep yourself on track, and should work sports drinks into the mix to replenish your carbohydrates and electrolytes. Finally, don’t forget to rehydrate after your run to restore those fluids!