How Long Does Water Take To Hydrate You – Tips to Stay Hydrated


Hydration is key to having a great run, bike ride, or whatever type of workout you are doing. It’s not just to refresh you, but it performs the necessary functions to keep your body going strong.

The key to avoiding dehydration is drinking before you start feeling thirsty, but it’s difficult to stick to that when exercising. Chances are you’re already dehydrated before you take your first sip. This leads us to ask: how long does water take to hydrate you?

Understanding this will help you develop an optimal hydration strategy to stay healthy and at your peak performance.

Why Is It Important to Stay Hydrated?

Your body is made up of around 50 to 70 percent water. Every one of your cells is made up mostly of water, the blood is made of water in large part, and every organ also contains it.

It’s important to stay hydrated because the water in your body helps to:

  • Regulate your body temperature
  • Move nutrients through the body (via blood)
  • Remove waste materials from the body
  • Cushion the joints from impact
  • Lubricate joints during movement
  • Protect the brain and spinal cord from impact

Even mild dehydration can lower the effectiveness of these functions in your body. So you must stay well-hydrated to remain in optimal health, even if you aren’t actively exercising and losing fluid.

What Happens To Your Body When You’re Dehydrated?

Dehydration is quite common, and most people don’t even realize they’re suffering from it! It’s incredibly easy to dehydrate without even noticing, so most of us suffer from the effects of mild dehydration daily.

However, even just a 1 to 2 percent reduction in your body’s water content can begin to have noticeable effects on your brain and your cognitive abilities. You may find that it becomes more difficult to concentrate, tasks that would normally be easy for you to do become more difficult, and your reaction times slow down.

This is because the fluid in brain tissue decreases as you become dehydrated, which reduces brain volume and thus affects cognitive abilities.

In your body, dehydration has several undesirable effects. Your blood becomes more concentrated, so it struggles to pump nutrients and oxygen as efficiently as normal.

As a result, your heart begins to work harder to keep the blood circulating, increasing heart rate and blood pressure. Your body temperature is likely to increase, which is not only uncomfortable but can cause damage at a cellular level.

As dehydration progresses, your kidneys begin to retain water, causing you to urinate less. This means waste isn’t being removed from your body, as water is sent elsewhere to try and rehydrate.

If you’re active and exercise often, you’ll also notice that your performance suffers when you’re even mildly dehydrated. You’ll have less strength and stamina as your body directs the available water to more important processes.

As you can see, dehydration can wreak havoc on the body and brain! Even mild dehydration can have negative effects.

How Quickly Do You Become Dehydrated?

Your body is constantly using water in processes. The respiratory process, urination, defecation, and sweating cause you to lose more water than you realize.

You breathe all the time, which means you’re losing water. Even in cool weather, moisture is lost through the skin in order to maintain your body temperature.

While we replenish this water loss through both eating and drinking, we can become dehydrated much faster than you realize.

While the exact numbers would be different for everyone and in every situation, to put it into perspective, when you get thirsty, you’re already dehydrated.

The trigger to make you feel thirsty only happens when your body is already experiencing the effects of dehydration. Thankfully, you won’t be suffering from any of the most severe effects yet, so if you take a drink at this point, it should help.

How Long Does Water Take To Hydrate You?

The answer to this question depends on how dehydrated you are, what you choose to rehydrate with, and if your stomach is full or empty.

Water moves through your digestive system in about 15 minutes when you’re well hydrated. However, research indicates that when you’re mildly dehydrated, you can rehydrate in about 45 minutes with about 20 ounces of water.

Naturally, the more severe your dehydration, the longer it will take and the more water you’ll need to drink. Severe dehydration may require an IV line with a carefully-timed reintroduction of fluid to bring the body back to optimal nutrition.

It’s interesting to note that eating food and rehydrating adds time to your rehydration. This may be because some water goes toward digestion, and the remaining water has to wait for the digestive process to finish before it can move to rehydrate the body.

How to Stay On Top of Your Hydration

The best way to stay hydrated is to drink water throughout the day so that you never actually feel thirsty. This is a reliable way to tell that you’re staying well-hydrated and that your brain and body shouldn’t be affected.

However, it may take some time to get used to carrying water around with you, or even remembering to take a sip every few minutes. Here are some tips to stay on top of your hydration.

Do Your Best to Avoid It

If you’re just hanging around at home, or you’re in the office, make sure you’re constantly sipping from a bottle of water.

On the occasions when you exercise, you’ll need to increase your water intake but do your best to continue drinking throughout your workout as well.

The best way to avoid the negative effects of dehydration is not to become dehydrated! It might be difficult to get into a habit, but it will be worth it.

You may want to consider a few different ways to carry water with you while you’re running. If holding a water bottle is uncomfortable or difficult for you, opt for a running belt or even a vest with a bladder. Whatever might help you to drink more during exercise is a good way to avoid dehydration.

Learn to Recognize the Signs of Dehydration

If you recognize the signs and symptoms of mild to moderate dehydration, you’ll be much less likely to ever be at risk of severe dehydration.

As we’ve already mentioned, when you feel thirsty, that’s the first sign of mild dehydration. But here are some others you should be looking out for:

  • Fuzzy head or headache
  • Dizziness
  • Nausea or vomiting
  • Dry mouth
  • Unusual fatigue
  • Dry skin

If you don’t rehydrate at this point, it can progress to moderate dehydration and then severe dehydration. The following symptoms are signs of more severe dehydration that’s a medical emergency:

  • Low blood pressure
  • Rapid heartbeat
  • Darker-colored urine
  • Lack of sweat when there should be

Choose the Right Kind of Hydration

If you’re rehydrating during the day without exercise being a factor, then plain water is enough. You can also use plain water during and after less intense workouts.

You may want to consider adding electrolytes to the mix when you’re doing a hard workout or exercising for longer than an hour.

If you’ve been rehydrating well up to this point, the consistently added water can cause the water and electrolytes to become unbalanced in your body. You’ll need to replenish these as you go to continue feeling good.

You can find electrolyte solutions of various types. Some are plain salt tablets, designed to replenish sodium levels. Others include sodium, magnesium, potassium, and others.

Other oral replenishment solutions contain glucose as well, which helps to give you an energy boost. You can buy sodium tablets or electrolyte tablets to add to your water so you can drink them mid-run.

Figure Out How Much You Lose When You Sweat

It’s a good idea to do this every few months. The key is to weigh yourself before and after the run or whatever other exercise you’re doing. Remember to weigh yourself with no clothes on for the most accurate results!

If you lost, for example, 2 lbs in your before and after weighing sessions, you want to replenish with 3 lbs—around 46 ounces—of water after your exercise.

Rehydrate Over the Next 2 to 4 Hours

While you may calculate needing to rehydrate with anything from 30 ounces upwards of water after your exercise, you’ll be pleased to know that you don’t have to down it all in one go!

It works best when taking in this water for two to four hours after exercise. Drinking it all in one go will make you feel uncomfortable and bloated, so drinking it over a few hours will help you to rehydrate effectively and without discomfort.

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Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.

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