The question: Confession: I don't drink even close to the American College of Sports Medicine’s recommended three to eight ounces of a sports drink every 15 to 20 minutes during my long Chicago Marathon training runs. If I'm being totally honest, I sometimes run nine-plus miles without sucking down any fluids. (I know, I know, my running buddy routinely calls me out on this and attempts to share her water and get me to sip from every fountain we pass!) But, also in the interest of full disclosure, I rarely feel the symptoms of dehydration (cramps, dizziness, fatigue), and if I do, I stop and buy some H20! So: Just how bad is that?
The expert: Lauren Antonucci, R.D., owner/director of Nutrition Energyin New York City (and an athlete herself!)
The answer: First off, there's a big difference between must drink H20and should drink H20, says Antonucci. "Could we go for a 10-mile run [without stopping for water] and finish and be OK? Probably, yes," she says. "But, why do that? Why make it harder?" (And why even risk dehydration and heat stroke, which are both super serious?) Turns out, having the right balance of water and sodium (yup, you lose this important electrolyte in your sweat, too!) helps you ward off hitting "the wall" mid-run and could help you be more efficient, says Antonucci. Plus, if you're dehydrated, you’ll likely finish your run starving, and feel fatigued for the rest of the day.
I’ve experienced both of these things and simply chalked it up to "normal" side effects of a long run. I'm interested to see if changing my ways—and hydrating on the run—helps me feel less "run-gry" and fatigued mid-day. But now that I’m convinced that I should up my fluid intake, I have no idea where to start. What and how much/often should I drink?
Unsurprisingly, there's no one-size-fits-all answer for everyone, according to Antonucci. But, what is surprising is how different your needs are based on your body size (smaller people need less fluid), your sweat rate (some of us are just heavier sweaters!), and the climate (obviously you need more fluid on steamier runs). But here, some basic hydration rules for runs lasting over 60 minutes:
Get a Head Start
If you go into a run dehydrated, you can’t play catch up while you’re out there. Again, there’s no "right" amount of water to drink before you run, but be sure your pee is pale yellow before heading out the door, says Antonucci.
Start with a Standard
How much you need to drink on the run depends on how much you sweat. "Most people sweat at a rate of 24 to 32 ounces an hour while exercising—and should aim to replace at least 75 percent of that on the run," says Antonucci. That means drinking 18 to 24 ounces an hour while running. But, like we said, that sweat rate differs for everyone, so…
Take a Sweat Test
"We should put a scale at the entrance to Central Park and let people weigh themselves before and after their runs," says Antonucci (half-) jokingly. Weighing yourself pre- and post-run helps you determine how much sweat you lose on the run. That, in turn, helps you discover whether you’re staying adequately hydrated—or if you should sip more or less next time you run. We probably won’t get scales in major parks anytime soon, but you can (and should!) weigh yourself before and after you next run and note how much weight you lost. If it’s more than two percent of your bodyweight, that’s a sign you need to drink more the next time you run, says Antonucci.
Sodium Matters, Too
If you have salt caked on your face and arms after you run, that’s a sign you lost a lot of the stuff (again, everyone has different rates!), so you need to take in more sodium next time you run. "People are always amazed how much better they feel when they add salt to their water or swap water for a sports drink," says Antonucci. Most people lose 800 to 1500 mg of sodium per hour in their sweat, so sprinkle a little actual salt in your H20 (you can also add a bit of honey for flavor and carbs), or make sure there’s some in your fueling option of choice. (Eight ounces of Gatorade has 110 mg; Gatorade Endurance has 200 mg.)
The bottom line: Your risk of becoming dehydrated is much more likely than being overhydrated. So, even though you'd probably see signs of dehydration (like dizziness, cramps, etc.) before you’d suffer any major issues (like heat stroke), determining your sweat weight and drinking during your run is definitely a smart idea.