Sports drinks are worth reaching for when you’re exercising hard for longer than 60 minutes, especially in the heat. For anything shorter or less intense, water does the job. The 60-minute mark is where your body starts running low on its stored carbohydrates and losing enough sodium through sweat that plain water can’t fully replace what you’re losing.
The 60-Minute Rule
During the first hour of exercise, your body has enough stored fuel (glycogen) to keep you going, and your electrolyte losses are modest enough that water handles rehydration just fine. Once you push past 60 minutes of continuous, moderate-to-high intensity activity, two things change. First, your glycogen stores start depleting meaningfully, and the carbohydrates in a sports drink help maintain your blood sugar and energy output. Second, cumulative sodium loss through sweat becomes significant enough to affect performance and fluid balance.
If you’re exercising beyond 90 minutes, the guidance gets more specific: drink 8 to 10 fluid ounces of a sports drink every 15 to 30 minutes. For very long endurance efforts over two and a half hours, like marathons or long cycling rides, aim for 60 to 90 grams of carbohydrates per hour. Research shows that exceeding 90 grams per hour doesn’t provide additional benefit, so more isn’t better.
Heat and Humidity Change the Equation
Hot weather can compress the timeline. Your body loses fluid through sweat at dramatically different rates depending on conditions. In a cool environment at rest, you might lose about 500 milliliters of water through your skin over an entire day. During exercise in the heat, that number can spike to over a liter per hour. Studies measuring sweat rates in hot, dry conditions found athletes averaged about 1,200 milliliters per hour, while hot and humid conditions produced around 700 milliliters per hour (though with higher core temperatures, since less sweat actually evaporates).
This matters because the more you sweat, the more sodium you lose. Sweat sodium concentration varies widely between individuals, ranging from roughly 230 to 1,600 milligrams per liter. If you’re a heavy sweater exercising in 90-degree heat, you could lose meaningful amounts of sodium in well under an hour. In these conditions, a sports drink may help even during shorter workouts, particularly if you notice salt crusting on your skin or clothing after exercise.
Before and After Exercise
Pre-hydrating with a sports drink can be useful before long or intense sessions. Johns Hopkins Medicine recommends drinking about 24 ounces of a sports drink or electrolyte-infused water roughly two hours before activity. This gives your body time to absorb the fluid and top off sodium levels before you start sweating.
After exercise, sports drinks outperform plain water for rehydration. In a study comparing water, a standard sports drink, and an oral rehydration solution after exercise-induced dehydration, both the sports drink and the rehydration solution retained significantly more fluid than water alone. After three and a half hours of recovery, water retained only about 58% of the fluid consumed, while the sports drink retained about 74% and the rehydration solution about 77%. The sodium in these beverages is the key factor: it helps your body hold onto water instead of flushing it out as urine. Beverages with higher sodium concentrations were especially effective at suppressing urine production in the first hour after drinking, which can matter if you need to rehydrate quickly between events or training sessions.
When Sports Drinks Can Backfire
A typical 20-ounce sports drink contains around 34 grams of sugar and 140 calories. If you’re doing a light jog for 30 minutes or playing a casual weekend pickup game, you’ll likely take in more calories from the drink than you burned during the activity. The sugars in sports drinks, usually sucrose or high-fructose corn syrup, behave the same way metabolically as sugars in soda. Fructose in particular is processed in the liver and can promote fat accumulation around the organs, raise triglycerides, and contribute to insulin resistance when consumed regularly without the exercise intensity to burn it off.
This is a real concern because sports drink marketing has made these beverages feel like a healthy, everyday choice. For people who aren’t exercising intensely, they’re essentially sugar-sweetened beverages with some added salt. Regular consumption of sugary drinks is strongly linked to increased risk of metabolic syndrome and type 2 diabetes.
Kids and Sports Drinks
The American Academy of Pediatrics is clear on this: water should be the primary hydration source for children and adolescents. Sports drinks have a “specific limited function” for young athletes engaged in prolonged, vigorous activity. For the average kid at soccer practice or in the school lunchroom, sports drinks are unnecessary. The concern is both the added sugar and the habit formation. Kids who routinely drink sports drinks outside of intense activity are simply consuming extra calories and sugar with no physiological benefit.
Young athletes who are training hard for extended periods in the heat can benefit from sports drinks the same way adults do. The threshold is similar: prolonged, intense activity where carbohydrate and electrolyte replacement genuinely helps performance and safety.
Why Not Just Drink Extra Water?
Drinking large volumes of plain water during long endurance events carries its own risk: a condition called exercise-associated hyponatremia, where blood sodium levels drop dangerously low. This happens through two mechanisms. First, you’re diluting your blood sodium by flooding your system with sodium-free water. Second, during prolonged exercise, your body often continues releasing antidiuretic hormone, which prevents your kidneys from flushing the excess water. That combination can drop sodium levels enough to cause confusion, seizures, and in rare cases, death.
Interestingly, standard sports drinks contain only about 20 to 30 milliequivalents per liter of sodium, which isn’t actually enough to prevent hyponatremia on its own. The real protection comes from drinking to thirst rather than forcing fluids on a rigid schedule. Still, any sodium in your drink is better than none when you’re out for hours, and the carbohydrates serve the separate purpose of fueling your muscles.
A Quick Reference
- Under 60 minutes, moderate intensity: Water is all you need.
- 60 to 90 minutes, high intensity: A sports drink can help maintain energy and replace electrolytes.
- Over 90 minutes: Sports drinks become clearly beneficial. Drink 8 to 10 ounces every 15 to 30 minutes.
- Hot or humid conditions: Consider a sports drink earlier, even for sessions under 60 minutes if you’re sweating heavily.
- Post-exercise recovery: A sports drink helps you retain more fluid than water alone, especially if you need to rehydrate quickly.
- Light activity or rest days: Stick with water. The sugar in sports drinks adds calories without benefit.