Does Coffee Really Cause Dehydration?

In the competitive debate community, there’s a joke that debaters are mental athletes as much as other people are physical athletes. The primary difference lies in our tournament regimens: instead of fueling up on Gatorade or nourishing foods, debaters fuel up on coffee.

At the last tournament I went to, I myself was privy to a large double-double from Tim Hortons. In my first debate round, I found my mouth feeling dry as I spoke, so I drank more coffee. But the problem persisted.

I’m headed off to another tournament this weekend, and I definitely don’t want to feel as dehydrated this time around. So I did some research on my beverage of choice and…

Turns out, coffee is a diuretic.

Caffeine Consequences

Now, this isn’t as intense as my sentence formatting may have made it seem; a diuretic is just any substance that tells your kidneys to release more sodium and water. Specifically, diuretics oppose the function of antidiuretic hormone (ADH), a hormone produced by a part of the brain called the hypothalamus. ADH tells your kidneys how much water to conserve, and if its function is opposed, your kidneys will release more water through urination.

Here’s a video that explains the process in greater detail:

Scientists used to think that all diuretics were dehydrators, but recent research actually disproves that! Dr. Daniel Vigil from UCLA explains that “even though caffeine is a mild diuretic, you won’t lose more fluid through urine than you take in by drinking a caffeinated beverage”.

However, a study in the American Journal of Clinical Nutrition compared the hydrating effects of several popular beverages to those of water. The results found that coffee (black Nescafe Original coffee to be exact) had the weakest hydrating effects out of all the drinks they studied. Water is still one of the best sources of hydration, and you should aim to drink more water than any other beverage.

A Coffee Conclusion

The fact of the matter is, coffee doesn’t cause dehydration. For me, though, it means that I can’t blame my symptoms of mild dehydration on my caffeine intake; I just need to be drinking other fluids. Maybe I’ll even get myself some Gatorade this weekend to feel like a real athlete…

Until next time,
👋