“How do I know if I’m hydrated enough for working out?”
One of the age-old questions we get, especially during the warmer months when it’s hot and humid. We all know we should drink liquids to stay hydrated year-round and it is even more important during the hot summer months. I often get asked by people how much they should be drinking to stay healthy and perform, and while the answer isn’t quite as simple as replacing the water you sweat, especially if you’re a CrossFit athlete, it also isn’t worth fretting about.
Basic Daily Hydration 
What counts as adding to your hydration status? Is water the only thing you can drink? Absolutely not! Do you have coffee or juice in the morning? That counts towards your daily total. How about fruit? It adds a little to your total as well.
Anything liquid you drink within reason (you know, not so much alcohol) adds to your total hydration. The takeaway is that you can have more than water to stay hydrated and be ready to perform at your best! Aim to take in roughly half your body weight in ounces daily.
Workout days
Pre-WOD
Workout days are a little different because they place more demand on your body as well as your hydration amount. Heading to the gym for a workout without having had anything to drink, is a recipe for a poor training session.
About two to three hours before heading to the gym, make sure you have 16-20 ounces of water. Then when you get to the gym, drink another 6-10 ounces to ensure you’re primed and ready to do your best.1 You shouldn’t feel like you have a “cotton mouth” or any difficulty swallowing. A little thirst is ok, but it shouldn’t debilitating!
During WOD
For most CrossFit WODs, we don’t need to drink much of anything during the actual workout. For example, if we’re pushing the pace on “Fran,” it’s a 2 min workout for those top RX athletes, and possibly closer to 7-10 minutes for those of us who scale back. That short time frame doesn’t warrant a need for more to drink (I’m looking at you and that water bottle Goans and others!).
However, on those longer AMRAPs of 20 minutes or more, or possibly a hero workout like we just knocked out with “Murph” we may benefit from a little-added hydration. Suggested amounts vary between roughly 3-12 ounces for every 15 minutes of physical activity2. In that case during ‘“Murph,” most of us would want to drink anywhere from 10-40 ounces to stay hydrated and perform well.
Long story short
In general, it’s safe to assume that for a one-hour class, having 20 – 24 ounces of water (or your beverage of choice) is adequate for rehydration. We likely haven’t lost much by way of electrolytes, outside of those really hot days, so water would really be the preferred source.
We’re always happy to discuss these types of topics specifically with athletes to ensure you are taken care of, so don’t hesitate to email us ([email protected]). Addressing your hydration specifically is important, but getting the right message is also key.
1Binkley, HM, Beckett, J, Casa, DJ, Kleiner, DM, and Plummer, PE. National Athletic Trainers’ Association Position Statement: Fluid Replacement for Athletes. Journal of Athletic Training 35(2):212-224, 2000.
2Sawka MN, et al. “American College of Sports Medicine position stand. Exercise and fluid replacement.”.Med Science Sports Exercise 2007;39:377-390. Accessed May 3, 2014.