The sun beats down on the pool deck and a dip in the water makes the summer swelter feel so much better. But, just because you are in the water doesn’t mean you don’t need water in you to perform at your best and stay healthy. Recently, several swimmers have asked about what and how much to drink, and if energy drinks should be consumed for hydration.

In the heat of summer, aim for about 1 cup of water (8-ounces) every 15-20 minutes of activity. Most sports water bottles are larger than 8-ounces, so mark your bottle at 1-cup intervals so you will know how much to drink. A less precise method is to count the number of swallows…a large swallow is about an ounce, so take 8 swallows of your drink when you get a break. Cold fluids are best, and with the advances in water bottles, keeping fluids cold is easier than ever. 

Dehydration of just 3-4% of your body weight can reduce muscle strength by about 2%. So, if you are losing power in the pool, check your hydration intake to make sure you are maintaining body fluid levels. For good information on hydration and performance, see the National Athletic Trainer’s website for young athletes.

It seems odd that dehydration can occur when you are surrounded by water, but anyone who exercises in the heat can be at risk for heat illnesses. The good news is that heat illness is 100% preventable by paying attention to the early warning signs such as dizziness, cramps, lightheadedness, and fatigue. Drink cold fluids and seek some shade until the symptoms pass.

What to drink is simple. I like the advice of my fellow USA Swimming nutrition columnist, Jill Castle, who uses the “over/under rule.” For activities over an hour, drink sports drinks, and if exercising less than an hour, drink water. (For more tips from Jill’s book, Eat Like a Champion, visit her website at jillcastle.com). A good strategy for a swimmer is to drink sports drinks and then drink water. So, it isn’t always either/or, just a bit both can be effective and your taste buds happy.

And, what about energy drinks? I do not recommend energy drinks for young swimmers, and I think they can be dangerous. Caffeine is a drug, widely consumed, but still a drug. Energy drinks deliver quite a punch of caffeine. Unlike coffee, energy drinks can be consumed quickly, so a swimmer may not know how much caffeine he or she is truly getting. Don’t be fooled by the new breed on energy drinks that claim to be “natural,” “clean,” or made with “healthy ingredients.” They still contain caffeine and sometime other stimulants that no young swimmer needs. 

So, this summer, stay hydrated with water or sports drinks, pay attention to the early warning signs of heat illness, and have fun!

Chris Rosenbloom is a registered dietitian, certified specialist in sports nutrition, and professor emerita of nutrition at Georgia State University. She welcomes questions from swimmers, parents and coaches. Email her at chrisrosenbloom@gmail.com; follow her on Twitter @chrisrosenbloom.