Can hot drinks really cool you down?

It sounds completely backwards. After all, adding something hot to an already hot body should make you warmer- not cooler. But research suggests that drinking a hot beverage can actually reduce the amount of heat stored in your body under the right conditions.

In controlled laboratory studies, participants who consumed hot water while exercising produced more sweat than those who drank cooler beverages. When that sweat evaporated efficiently, the additional heat lost through evaporation outweighed the small amount of heat gained from the drink itself.

In other words, the hot drink isn't cooling you directly. Instead, it encourages your body's own cooling system to work harder.

How does it work?

The secret lies in your body's remarkable ability to regulate its internal temperature. When you drink a hot beverage, heat-sensitive receptors in your mouth and throat detect the increase in temperature. These receptors signal your brain that additional cooling is needed, triggering increased sweating.

Sweat itself doesn't cool you. The cooling occurs when sweat evaporates from your skin, carrying heat away from your body. If a hot drink causes you to produce substantially more sweat, and that sweat evaporates effectively, you can actually lose more heat than you gained from the beverage.

Researchers believe this exaggerated sweating response explains why people drinking hot beverages can end up storing less heat overall than people drinking cold drinks under certain conditions.

Why humidity changes everything

This is the part that's often overlooked: for sweating to cool your body, it must evaporate. If sweat simply drips off your skin or soaks into your clothing, very little cooling occurs.

That's why the benefits of a hot drink depend heavily on your environment. In hot, dry climates with good airflow, sweat evaporates quickly. Under these conditions, drinking a warm cup of tea or coffee may genuinely promote greater cooling than an iced drink.

Humid weather is another story. When the air is already saturated with moisture, sweat evaporates much more slowly. In these conditions, the extra sweating triggered by a hot drink provides little additional cooling while the beverage still introduces heat into the body. As a result, cold drinks are generally the more comfortable and practical choice in muggy weather.

What about coffee?

The same basic physiology appears to apply whether you're drinking tea, coffee, or simply hot water. Some people worry that coffee might contribute to dehydration because caffeine has a mild diuretic effect.

However, evidence from a controlled crossover study has shown that that the water contained in a normal cup of coffee more than offsets this effect, meaning moderate coffee consumption still contributes to your daily fluid intake.

That doesn't mean coffee should replace water during extreme heat, but there's little evidence that your morning cup is likely to leave you dehydrated simply because it's caffeinated.

So, what should you drink to cool down?

The answer depends less on the drink itself and more on your surroundings. If you're in a hot, dry environment where sweat evaporates easily, a warm beverage may stimulate enough extra sweating to produce a small net cooling effect.

If you're in hot, humid conditions, or wearing clothing that traps sweat against your skin- a cold drink is likely to feel better and may be the more sensible option.

Ultimately, the most important factor isn't whether your drink is hot or cold. It's staying well hydrated. Whether that's a steaming cup of tea on a dry summer afternoon or an ice-cold glass of water during a humid heatwave, adequate fluid intake remains your body's best defence against overheating.

Lead photo by Amin Zabardast on Unsplash.