How Much Water Should I Drink As A Runner?

In the midst of all the pressure that comes with competitive marathon running, it’s easy to lose sight of the fundamental nutritional requirements for long-distance running. 

Runners often rely on thirst as a cue to drink water.

This might sound logical, but studies have shown that by the time you feel physically thirsty, up to 2% of your body’s water has already been depleted, which means that you’re already dehydrated. 

However, consuming too much water while running can have dangerous health implications, too.

In fact, there have been 8 recorded cases of running-related deaths by hyponatremia (sodium deficiency caused by excess water) in the last few decades. 

So, how much water should you be drinking as a runner? Stick around to find out!

How Much Should I Hydrate Before Running?

The key to staying hydrated while running is to hydrate sufficiently before your run, as opposed to during it. 

Of course, this doesn’t mean you shouldn’t be drinking water intermittently during your run (we’ll get into this in more detail shortly), but hydrating yourself before running will help to lubricate your joints and facilitate the transportation of nutrients around your body, both of which are crucial for a good run. 

If possible, try to hydrate an hour to an hour and a half before running. Most guidelines recommend consuming 2 cups of water (16 ounces) roughly this long before your run. 

You should also hydrate closer to the time, about half an hour to 15 minutes before you’re due to run. At this point, you should try to drink roughly an extra cup of water (or between 6 and 8 ounces). 

Do I Need to Drink Water During a 5K? 

Whether or not you need to drink water during a 5K run will depend on how long this distance typically takes you to complete. 

There are runners out there who can smash out a 5K run in 20 minutes, while others take closer to an hour. 

If you know you can complete a 5K in 20 to 30 minutes, and you’ve hydrated sufficiently beforehand, you may not need to drink water during the run.

However, we’d still recommend bringing a small bottle of water with you if the weather is hot or you’re running a route you haven’t tried before since unexpected conditions can drag out your time, and you don’t want to be caught out without water if you get thirsty. 

Regardless of whether you feel like drinking during your run, you’ll need to replenish your body’s water supply afterward, so it’s worth having a bottle handy. 

On the other hand, if your average 5K usually takes upwards of 40 minutes, you will definitely need to top up your hydration levels on the go. Take small sips, and don’t drink more than 4 ounces every quarter of an hour. 

This 16-Ounce BPA-Free Glass Water Bottle from Lifefactory is perfect for hydrating before and during a 5K run. Since it holds 16 ounces when filled to the top, you can simply fill it up all the way an hour and a half before your run and about halfway in the half-hour to 15 minutes before you start.

Then, just before you run, fill the bottle up again to last you the duration of your run! You shouldn’t finish all 16 ounces during the run unless it takes you longer than an hour, but this will leave you with some refreshment left for after the run. 

The bottle has a protective silicone sleeve in case you drop it, although the convenient handle at the top makes it an easy bottle to carry during exercise. 

Should You Drink Water During a 10K?

When it comes to running a 10K, you’ll most likely need to hydrate at some point during your run, especially if the weather is hot. 

The average time for completing a 10K is 60 minutes, with even advanced runners usually taking about 45 minutes to finish.

 That means that, unlike a 5K run, which can be completed in 20 minutes by fast runners, a 10K run is likely to see you out on the track for at least 45 minutes. That’s a long time to go without water, especially if the sun is beating down on you. 

However, overhydrating is a risk during 10K races. Runners often become obsessed with drinking water during the race, thinking it will enhance their performance, but the reality is that they may actually be putting themselves at risk of hyponatremia by drinking too much. 

Experts do not advise drinking more than 500 ml (16 ounces) of water per hour of running. Since the average 10K time is 60 minutes, that means you shouldn’t be drinking more than 16 ounces over the course of the race, or 4 ounces every 15 minutes. 

Again, a water bottle similar to the 16-Ounce BPA-Free Glass Water Bottle is ideal for this distance and length of time.

Final Thoughts 

All in all, research shows that drinking water before running is the best way to stay hydrated and strengthen your performance during the race. 

The most important thing to remember in terms of hydration for runners, therefore, is to consume at least 16 ounces of water an hour to an hour and a half before you run.

If you can, try to get another cup or so in during the last 30 to 15 minutes before the race. 

If you can run a 5K in under 30 minutes, you may not need to drink water on the go.

However, if your 5Ks take over 40 minutes, you should take some water with you and sip it slowly and sparingly as you run, not exceeding 4 ounces every 15 minutes.

Most people will feel the need to hydrate at some point. However, the same rules that apply to the 5K run also apply to the 10K: focus on hydrating well beforehand and don’t drink more than 16 ounces (500 ml) in an hour.