Andrew Dole, RDN
Everyday Chef & Performance Nutrition Expert, Fruits & Veggies—More Matters Full Bio
Summer brings warmer weather and sunshine; both very welcome after a winter of exercising inside. As you move activities outdoors and into warmer conditions, it is important to adjust your hydration strategies to meet increased demands. How much, how often, and what should I drink during exercise are three very common questions. The answer to all of them? It depends on you.
For serious athletes hydration should be individualized. How long you are exercising, how much you sweat, how old you are, and temperature ranges are all factors that contribute to a hydration strategy. But even if you’re not racing or training for competitive events, hydration is still important. Long hikes, all-day outings, and long family rides in hot weather can lead to dehydration-related headaches, fatigue, and irritability. Avoid cutting summer activities short by following these guidelines for both an active lifestyle and the demanding competitor.
How To Stay Hydrated Before, During & After Exercise
Starting with adequate hydration 4 hours before activities is an important first step. The Academy of Nutrition & Dietetics and the American College of Sports Medicine recommends 5-7ml of fluid per kilogram of body weight. An easy way to estimate would be approximately 1 ounce for every 10 pounds of body weight.
For activities lasting 60 minutes or more be sure to hydrate on a schedule. Don’t rely on thirst to tell you when to drink. 6-8 ounces of fluid every 15 minutes is a good guideline to stay hydrated as an adult. Drinking on a schedule becomes increasingly important at age 40 or older when total body water and thirst sensation begins to decrease.
On average, a person loses about 16 ounces or 1 pound of water per hour of activity. A good rule suggested in the sports nutrition practice manual from the Acadamy of Nutrition and Dietetics is to replace body weight loss with 1 to 1.5x the amount of fluid and electrolytes within 2 hours of completing the activity.
What To Drink
For activities 60 minutes or less water is a good choice. However, for activities lasting longer than an hour an electrolyte replacement (see below) is recommended.
Individualizing for the Athlete
Training duration, sweat rate, age, and temperature are all factors that contribute to a hydration strategy. Sounds complicated, but getting the answers to these questions is not.
Try using a hydration worksheet to collect information from your workouts. Just plug the information provided into a quick equation to determine how much fluid to recommend each hour.
Pre-exercise weight – post-exercise weight x 16 + fluid intake during exercise / duration = estimated intake per hr
Compensating for electrolyte and sodium losses is also a key component for any endurance hydration plan. For endurance and multisport training, I recommend an electrolyte replacement mix with adequate sodium (approximately 300mg per 12 ounces) when training for 90 minutes or longer.