Water is the first thing to reach for during heat exhaustion, but it’s not the best option on its own. A drink that contains both a small amount of sugar and sodium will rehydrate you faster because those ingredients help your intestines absorb water more efficiently. The ideal choice is an oral rehydration solution or a dilute sports drink, sipped steadily rather than gulped.
Why Plain Water Isn’t Enough
When you’re overheated and sweating heavily, you lose more than water. Sweat carries roughly 1,000 mg of sodium per liter, along with smaller amounts of potassium and other minerals. Drinking plain water replaces the fluid but not the electrolytes, which can dilute your blood sodium further and slow your recovery.
Your small intestine has a specific transport system that moves sodium and glucose (sugar) together across the intestinal wall, and water follows them. This is why a drink with a small amount of salt and sugar gets absorbed significantly faster than water alone. A study of outdoor workers in extreme heat (wet bulb globe temperatures around 86°F) found that those drinking an oral rehydration solution reported measurably less fatigue than those choosing their own beverages, which were mostly tea and coffee.
The Best Drinks for Heat Exhaustion
An oral rehydration solution is the gold standard. These products, available at most pharmacies, contain a precise balance of sodium, potassium, and glucose designed to maximize absorption. They’re the same formulations used worldwide to treat dehydration from diarrheal illness, and they work just as well for heat-related fluid loss.
A dilute sports drink is a reasonable second choice. Look for one that’s lower in sugar, closer to a 2% to 6% carbohydrate concentration. The American College of Sports Medicine recommends fluids containing roughly 460 to 690 mg of sodium per liter during heavy exertion in heat. Most standard sports drinks fall in this range, though some of the newer “enhanced water” products contain too little sodium to be useful.
If you don’t have either option, you can make a basic rehydration drink at home: about half a teaspoon of table salt and six teaspoons of sugar dissolved in a liter of water. It won’t taste great, but it works.
What About Coconut Water?
Coconut water is often marketed as a natural sports drink, but it has a significant gap for heat exhaustion recovery: it’s too low in sodium. While it contains decent potassium, the sodium content of plain coconut water falls well short of what you’re losing through sweat. Researchers have noted that coconut water needs added sodium and carbohydrates to match the rehydration performance of a sports drink. It’s better than nothing, but it shouldn’t be your first choice if something with more sodium is available.
Drinks That Make Things Worse
Some beverages actively work against you when you’re already overheated.
- Alcohol inhibits your body’s antidiuretic hormone, the signal that tells your kidneys to hold onto water. The result is increased urine output at exactly the moment you need to retain every drop of fluid. Even a beer after working in the heat can push you deeper into dehydration.
- Very sugary drinks like fruit juice, soda, or energy drinks with high glucose concentrations create a problem in your gut. Hypertonic beverages (those with more dissolved particles than your blood) actually pull water out of your bloodstream and into your intestines temporarily. One study comparing a 2% glucose solution to a 10% solution found that the concentrated version caused a transient drop in plasma volume. Your body eventually corrects this through hormone responses, but during heat exhaustion those 30 to 60 minutes of reduced blood volume can be dangerous.
- Caffeinated drinks have a mild diuretic effect. Caffeine blocks a receptor in your kidneys that normally helps reabsorb sodium, leading to increased water loss in urine. For someone already dehydrated from heat, this adds an unnecessary burden. Coffee and tea were the most popular free-choice beverages among the outdoor workers in the study mentioned above, and those workers performed worse on fatigue measures than the group drinking oral rehydration solution.
Should You Take Salt Tablets?
Salt tablets are a common recommendation in endurance sports circles, but the evidence for them is mixed, and the risks aren’t trivial. A study of trained endurance athletes found that high-dose sodium supplementation (900 mg per hour) had no significant effect on sweat rate, skin temperature, perceived exertion, or time to exhaustion. One participant couldn’t even finish the trial due to gastrointestinal distress from the first capsule.
The bigger concern is that concentrated salt hitting an already stressed stomach can cause nausea and vomiting, which worsens dehydration. You’re better off getting your sodium dissolved in fluid, where it’s absorbed gradually and triggers less gut irritation. If you do use salt tablets, take them with plenty of water, never on their own.
How Much and How Fast to Drink
Sip rather than chug. Drinking too much too fast can trigger nausea, especially when your body is already under heat stress. Aim for about 1 to 1.5 liters over the first hour, taken in small amounts every few minutes. Cool or cold fluids are preferable because they help lower your core temperature slightly and tend to be more palatable when you’re overheated, which means you’ll drink more of them.
If you’re helping someone with heat exhaustion, watch for signs that oral fluids aren’t working. Confusion, inability to keep fluids down, loss of consciousness, or a core body temperature reaching 104°F (40°C) or higher all signal that the situation has escalated beyond what drinking can fix. At that point, the person needs emergency medical care and likely intravenous fluids to recover safely.