Do electrolyte drinks improve endurance?

What the reviews found

A 2026 meta-analysis pooled 21 studies with 316 people who exercised at 22 °C or warmer. It compared carbohydrate-electrolyte drinks with water or a drink without calories.^[1]

• Overall, the drinks gave a small average gain (Hedges' g 0.37, a standard measure of effect size).^[1]
• The gain was clearest for aerobic endurance (g 0.45).^[1]
• For sprint endurance, power and strength, the results were not clear.^[1]
• The range of expected results crossed zero, so some settings may show no gain.^[1]

A 2017 meta-analysis of 9 cycling studies compared drinking with not drinking at 20 to 33 °C:^[2]

• in hard cycling of 1 hour, drinking lowered performance by 2.5%^[2]
• in moderate cycling of 1 to 2 hours, drinking raised it by 2.1%^[2]
• in moderate rides of more than 2 hours, drinking raised it by 3.2%^[2]

The gains came with 0.15 to 0.20 mL of fluid per kg of body weight per minute for rides of 1 to 2 hours. For longer rides, drinking to thirst or 0.14 to 0.27 mL per kg per minute worked.^[2]

A 2022 meta-analysis of 28 studies looked at blood volume during continuous exercise. Carbohydrate-electrolyte drinks that were less concentrated than blood (hypotonic) kept blood plasma volume best. The first author had earlier received funding from drink makers.^[3]

Does extra salt help

The two trials of salt in triathlon disagree:

• In 26 triathletes in a half-ironman race, salt capsules with 113 mmol of sodium led to a faster race time and higher blood sodium than a dummy capsule.^[4]
• In 413 athletes in a full Ironman race of about 12 hours, some took salt tablets (620 mg of table salt, 1 to 4 an hour). Their finish time and blood sodium were the same as in athletes who took dummy tablets or no tablets.^[5]

How much sodium people lose in sweat differs a lot between people.^[6]

Too much water is also a risk

Low blood sodium (hyponatremia) can develop in as many as 2% to 7% of people in endurance events. It comes from drinking too much water or dilute fluid while a hormone, vasopressin, makes the kidneys hold water.^[7] Its signs are bloating, vomiting, headache and confusion, and a severe case is a medical emergency. Drinking to thirst is the most individual way to prevent it.^[8]

Short workouts

In a trial of 12 people who cycled for 60 minutes at about 33 °C, water, a sodium-potassium drink and coconut water gave the same results.^[9]

What is still unknown

The studies in the 2026 review were small: 316 people in total.^[1] Most tested one session, and the review does not show that the drinks make up for the effect of heat.^[1]