Let’s say it’s dinner time and you’ve only had one glass of water so far today. Yikes! Your plan was to drink six glasses in total, so you’d better hurry up and chug down a bunch of H2O before bed, right? Well… no. It’s not a great idea to consume a ton of water in one go, and not just because of the horror stories you may have heard about acute water intoxication.¹

In our hypothetical above, it’s a bit late to make up for all the day’s hydration, but that shouldn’t stop you from practicing better pacing when you drink water tomorrow. Here are some important reasons to avoid chugging water, and stick to sipping it throughout the day:

Too much water, too fast means frequent urination

The human body is an amazing natural machine that can operate for decades! However, the body has certain limitations, one being that it can only absorb so much water at a time. Consuming more than your body needs at any given time increases your elimination rate — that is, you’ll be running to the bathroom pretty often!

How can you know if you’re consuming too much at once? According to Dr. David Nieman of Appalachian State University, “If you’re drinking water and then, within two hours, your urine output is really high and your urine is clear, that means the water is not staying in well.”² In other words, although we’re told that clearer urine is better than a dark yellow shade, frequent urination of clear liquid suggests that you’re not pacing yourself when it comes to drinking water.

Overhydrating knocks your electrolytes out of balance

Water is great, but it also has a great impact on the balance of electrolytes in your body such as sodium and magnesium. You’re always ingesting these things in food, and may take in even more in the form of supplements. What’s more, every person has different electrolyte needs according to their diets (more for keto, for instance) and their health conditions (less sodium for hypertension).

So where does hydration come in? Taking sodium for example, drinking too much water in a short amount of time can dilute the amount of sodium in your system. In extreme cases, drinking too much water quickly can lead to what’s called hyponatremia³, and can cause nausea, fatigue, or even coma. People who engage in long distance running or people with low body weight can be particularly at risk for this.

Drinking too much water can cause headaches

Even though many of us are familiar with the symptoms of dehydration, or drinking too little water, it may come as a surprise that headaches can also be caused by drinking too much water. This happens because water causes cells to expand, and if consumed in excess, that extra body water can appear in the form of swelling, even in the brain.⁴ Weird, right?

To avoid this happening, pay attention to what your body is telling you, and you’ll get a true sense of whether you’re truly thirsty or just sipping out of habit. (Even better, track your water intake and use reminders to sip small amounts throughout the day instead of large amounts all at once!)