By Janice T. Radak, Editor
With summer upon us, I thought it a good time to see just how much water I should be drinking or encouraging my friends and readers to drink. So I asked Dr. Google. Yes, yes, I know what you’re thinking. But this was an exercise in perhaps the original form of data verification—get 1 answer and see if it can be replicated by a reputable source. So I asked, “how much water to drink when exercising?”
I got 21,400,000 results in less than half a second.
FamilyDoctor.org said “drink 7 to 10 ounces of water every 10 to 20 minutes during exercise. Drink 8 ounces of water no more than 30 minutes after you exercise.” So let’s assume I exercise for 30 minutes. That means I drink 8 ounces every 10 minutes (24 ounces) and then another 8 ounces within 30 minutes. Total = 32 ounces. There’s no mention of weight or age or health condition. But note, I didn’t go into the page itself—just took Google’s word for it, like the typical Google user.
New York Health said, “drink 17–20 ounces (500–600 ml) before working out, 8 ounces (240 ml) every 10 minutes during your workout, and another 16 ounces (480 ml) after you’re done.” Using the same 30-minute workout, here I drink 17–20 ounces BEFORE I even start, then I drink 24 (3 x 8) ounces during the workout, and another 16 after. Total = 60 ounces. Again, no mention of weight/age/health status. And again, just took Google’s word for it.
The listing from the University of Michigan was not enough to provide a quick answer, so I had to click through. This took me to a PDF file from M healthy titled, “The Importance of Water While Exercising,” dated 2011. The file offers the symptoms of dehydration for patients and its complications (very briefly) and then provides this response to the query: How much water should I drink?
Remember it is important to drink water before, during, and after exercise. Exact amounts of water needed will vary from individual to individual (gender, exercise environment, type of exercise, and intensity of exercise are all factors).
Before: 17–20 oz. of water at least 2 hours prior to exercise
During: 7–10 oz. of water for every 10–20 minutes of exercise
After: 16–24 oz. of water for each pound lost due to sweating
Hmmm, to calculate how much to drink with this, I have to weigh myself BEFORE and AFTER my exercise workout….so let’s say, my workout wasn’t very vigorous and I didn’t really sweat, so I didn’t lose a pound or 4. The New York Health guidance is very similar, just lacks the weight-loss stipulation for post-workout water needs. Total = 60+ ounces.
When I clicked on Google’s infamous “People also ask ‘How much water do you need per hour of exercise?’” Truesport.org took me to a page titled, “How Much Water Do Youth Athletes Need?” Searching on the site I learn that Truesport is the United States Anti-Doping Agency’s (USADA) youth sport outreach program.
This page is dated April 2017 and identifies proper hydration as “one of the most important steps a youth athlete can take toward achieving peak performance in their sport.” And it mentions that there’s “conflicting advice on how much water youth athletes should drink and when.” I want to tell them, it’s not just youth athletes who face such conflicting advice.
The good news is, Truesport goes on to explain the 4 ways fluids get lost—exercise intensity, sweating, temperature, altitude—and that some ways may not affect your particular performance (eg, I’m not at a high altitude).
And then it answers our key question with this straightforward advice:
A good rule of thumb for athletes is to divide their body weight in half and drink at least an ounce per pound of body weight throughout a typical day (e.g., someone weighing 160 pounds should drink 80 ounces of water a day). This amount should then be adjusted for the day’s activity level and outside temperature.
On high-activity days, the timing of hydration becomes an extra–important factor. As general rules of thumb, the following guidelines can be helpful:
Before Exercise: Drink 16 ounces of water 2 hours before physical activity begins, and another 8–16 ounces right before exercising.
During Exercise: Every 15–20 minutes, drink at least 4–6 ounces of fluid during vigorous exercise. For less vigorous exercise, decrease the amount slightly.
After Exercise: Drink 16–24 ounces of water for every pound lost during physical activity. Consuming rehydrating beverages (like fruit smoothies) and eating watery foods (such as fruits and vegetables) along with salty ones can help replace lost fluids and electrolytes.
A simpler way for most athletes (or anyone) [emphasis added] to drink enough water is to remember the Rule of 8: 8 times throughout the day, drink a big glass of water (8 total).
OK, so in this last scenario, I should aim for 8 big glasses of water 8 times a day. Let’s assume an 8-ounce glass 8 times a day. Total = 64 ounces. But it seems clear that if I did consider myself an athlete, I’d need a whole lot more.
So what to do? USADA’s advice seems most straight forward and more importantly, easiest to follow, so, like the average internet user, I’ll take that advice! Stay Hydrated!
Janice T. Radak is Editor of Lower Extremity Review and her chosen form of exercise is water jogging.
