Hydration Know H2ow: How Much Water Should You Drink?

Here are a few strategies for dialing in your fluid intake.

I like to “finish strong.” Maybe because I’m a cyclist, a sport where even friendly training rides can end in white knuckle, gonads-to-the-wall sprints. I like the idea of wringing out the sponge at the end of a workout in an effort to drain every, last drop of sweat.

Apparently, I did not do this in my recent hydration newsletter. While most of the intel within was fairly detailed, I faded out when it came to daily water recommendations, suggesting that perhaps you should choose your own watery adventure. My logic was that how much a person should drink varies quite a bit, so it’s best you figure it out yourself.

After receiving NPB athlete feedback, I realize that suggesting you should ostensibly “Use the Force” to figure out a hydration strategy wasn’t ideal for everyone, so let’s dig a little deeper into ways to assure you are drinking enough water.

Math-based solutions.

Two of the most popular water goal recommendations are “Eight cups per day” and “Half your body weight in ounces.” I lean towards the latter since it offers personalization based on body weight. Take your weight in pounds, divide it by two, and drink that number in ounces. If you weigh 170 pounds, that means you should drink about 85 ounces of water daily.

No one seems to know where this method came from. Occasionally, you’ll see it busted as a myth, which is silly. It’s like busting the “myth” that you should use a spoon to help roll your spaghetti into your fork. Manners aside, it works, so why bust it?

Backing my stance is this small study in the Journal of Water Resource and Protection. It points out that, since many people don’t drink enough water, it makes sense to offer guidelines, even mythological ones.

Just keep in mind that this is for your day-to-day water intake. It doesn’t account for exercise related hydration. For that, here are the American Council on Exercise recommendations:

• 17 to 20 ounces of water two hours before the start of exercise.

• 7 to 10 ounces of fluid every 10 to 20 minutes during exercise.

• 6 to 24 ounces of fluid for every pound of body weight lost after exercise.

The famous Pee Color Chart.

On the other hand, that hydration-determining pee color chart you see everywhere actually does have science backing it. It’s based on a 1994 study and a 1998 study done at the University of Connecticut Human Performance Laboratory, both led by Dr. Lawrence “Larry” Armstrong.

That 1994 study is well worth perusing, especially the part where subjects were made to walk on a treadmill for three hours wearing three layers of clothing, including a Tyvek jumpsuit like the ones government people wear in movies to protect against alien invaders and zombie infections. It’s worth noting that the scientists also inserted a 10cm probe up each subject’s butt to monitor internal temperature—indicating that aliens weren’t the only ones that the subjects should have been worrying about.

This research resulted in a Urine Color Chart that allows you to determine your hydration level based on the color of your pee.

You’ll find countless variations of this chart. Many feature different urine colors, including red and blue. While I, personally, don’t want blue urine, it’s not really a factor in hydration, so let’s keep our eye on the prize. The chart above comes from a company that Armstrong founded, so it’s probably spot-on.

If you’re going to use this method, keep in mind that the research used samples taken first thing in the morning, when urine is most concentrated, so I recommend using your morning pee as a base.

That said, you might come home from a long workout to discover #7 dark pee. You should certainly drink extra water to address that acute dehydration, but then use the next morning’s whiz to confirm you drank enough.

Not everyone buys into Armstrong’s strategy. Science writer Alex Hutchinson picks it apart in the “Thirst” chapter of his book Endure—which is well worth the read. I’m a little more into proactive hydration than Hutchinson appears to be, but I do agree with him when he paraphrases researcher Stephen Cheung, “not that you shouldn’t drink when you have the chance, but that you shouldn’t obsess about it when you don’t.”

In other words, don’t get weird about it unless you want to. If you have a few off days and your pee turns a funny color, don’t stress—unless it turns blue. Apparently, that might be bad.