With a record heat wave hitting significant parts of the northern hemisphere — including the U.S. and U.K. — everyone needs to find ways to beat the heat. While not as innovative as covering your windows in tin foil, drinking water is still a necessary step. After all, everyone needs to stay hydrated.
But are there best practices for staying hydrated? A lot of focus is spent on how many glasses of water you should drink in a day. In fact, the Apple Watch features a great app called Water Reminder that gives your personalized reminders for when you need to take another drink.
Still, nobody ever thinks about what temperature that water should be. When it’s hot out, the default reaction is just to grab the coldest water so you can cool down immediately. But is that the best choice?
We took a look at what some science and medical research had to say about the ideal temperature for drinking water, and we think we have the answer.
Perfect Water Temperature: The theory
Surprisingly, there is not a ton of research out there on exactly what temperature your drinking water should be for peak hydration.
When I played soccer, we were told that you want water that is not ice cold, but closer to room temp. This is because it will take longer for room temperature water to be processed by your body. The theory is that the body needs to heat the water you take in up to your normal body temperature. Ice water, logically, would be the worst water choice for this as it's the coldest.
I am not the only one who has heard this theory for what it is worth. When I pitched this theory to friends and colleagues, the response was, “That makes sense.”
But as much sense as it makes, is that theory actually correct? I did some digging and here is what I found.
Perfect Water Temperature: What the experts say
It turns out there is an ideal water temperature to ensure hydration, and it is around 60 degrees Fahrenheit (or 16 degrees Celsius). I found two studies done on this subject. One by the National Institutes of Health and the other by the Korey Stringer Institute at the University of Connecticut in partnership with Camelback. Both came up with similar findings.
The Korey Stringer Institute study was a bit vague in its results. It was focused not only on hydration but the palatability of water. Also, since it was done in partnership with Camelback, researchers suggested that you use a Camelback water bottle, but you can use any of the best water bottles out there.
Still, they did land on a result. The study showed that to enhance fluid consumption and maintain hydration, you should drink water kept between 10 to 20 degrees Celsius. This translates to 50 to 68 degrees Fahrenheit.
The NIH study was more specific. Researchers found that “Water at 16°C induced higher intake (6.4 ml/kg) together with lower sweating (0.54 ± 0.03 g), which can result in optimum level of hydration.” Granted, their study featured six subjects over the course of four days, but that makes it two studies that suggest 60 degrees Fahrenheit, or 16 degrees Celsius is the optimal drinking water temperature.
Dr. Brian Weiner agrees with these conclusions. In an interview with the Cleveland Clinic, he said that athletes tend to gravitate toward cold tap water. How did he define cold tap water? You guessed it — 60 degrees Fahrenheit, or 16 degrees Celsius.
He also said that water at this temperature cooled athletes faster, so if you are really trying to beat the heat, maybe break out the thermometer the next time you pour a glass of water and make sure you hit that optimal temperature. In the meantime, make sure to read out tips on how to cool down a room so you don’t overheat while you read the latest articles from Tom’s Guide. Or you can learn how to make your own DIY air conditioner to cool down your room.