Couple resting after exercising, drinking water

How Much Water to Rehydrate – The Science Of Hydration

It’s essential to beat the heat and stay hydrated throughout the day during the hot summer season. If you don’t, after spending some time in the sun, you may start experiencing dehydration symptoms.

There’s some science to staying hydrated and what you can do to stay cool and healthy when your body craves water. We’ll go through how to recognize dehydration, cure dehydration, rehydrate fast, and how much water you need to rehydrate.

Dehydration Symptoms

It may seem obvious to you when to tell if you’re dehydrated, but often when you are, you may not realize it. If you’re with somebody else, especially a young child or an older senior, you may not know they are dehydrated until more severe symptoms occur.

Here’s how to tell if you or someone you’re with is dehydrated. Symptoms of moderate dehydration include:

  • Dry mouth and lips
  • Dry skin
  • Feeling light-headed
  • Headache
  • Fatigue and sluggishness
  • Lack of concentration
  • Muscle cramps
  • Sudden changes in blood pressure or heart rate
  • Changes in body temperature
  • Having less urine

Any combination of these symptoms indicates dehydration. Often, mild dehydration can be resolved at home by rehydrating. But for severe dehydration, you or the person experiencing dehydration must seek medical care.

Who is at risk for dehydration?

Young woman drinking water after exercising in the park

While dehydration can happen to anyone, those most at risk of dehydration are: 

  • Infants and babies
  • Seniors
  • People with chronic illness or a long-term health condition, such as diabetes
  • Athletes or those performing high-intensity exercise constantly

How much water do I need to rehydrate?

Generally, it is recommended to drink a liter of water a day to stay hydrated. However, this can depend on your age, body, underlying medical conditions, and what physical exercise you are doing on that day. And for hotter days, your body will require more fluids to maintain proper hydration. 

If you are dehydrated, you will need to drink water as soon as you recognize the symptoms of dehydration. While it may be tempting to drink a liter of water at once, it is recommended you do not do this and instead drink slowly.

Drink a cup at a time and wait to see how your body feels. Suddenly drinking a ton of water at once can cause an upset stomach, nausea, vomiting, or diarrhea, so you’ll want to bring back fluids to your system slowly.

Drinking water with electrolytes or sports drinks can help speed up the process of rapid rehydration without upsetting your digestive system. 

How long does it take to rehydrate?

The time it takes to rehydrate can vary depending on how mildly or severely dehydrated you are. If you are experiencing mild dehydration, the body can rehydrate in 45 minutes with around 600mL of water.

For more severe dehydration, it can take longer and will usually require medical attention. The more dehydrated you are, the longer it will take for your body to recover.

Since your body has a lot of lost fluid, you need to feed it those fluids back, including the essential nutrients and minerals that water carries with it.

If you do not stay hydrated regularly, you can be dehydrated indefinitely. Some people may be taking medicine or have a medical issue that puts them in constant dehydration.

If this is the case, working with your doctor to stay hydrated while still benefiting from your medication is essential.

Best Ways to Rehydrate

Senior woman drinking from a reusable water bottle after exercising


The best way to rehydrate is simple – drink some water! Ensure you continually drink water on hot days to stay hydrated throughout the day and avoid dehydration. Water contains no added calories, sugars, or chemicals, so it’s the best way to stay hydrated.

Electrolyte Beverages

For high-intensity workouts or sports, an electrolyte sports drink can rehydrate your body and give it the energy it needs to perform at high levels.

If you regularly work out and need electrolyte drinks, consider adding those nutrients to your daily meals, especially after a workout. Often, water is the best way to stay hydrated. 

For anyone experiencing dehydration, drinking fluids with electrolytes can be beneficial to providing energy and rehydrating. If you want to avoid beverages with added sugar, you can also purchase electrolyte powder to add to your bottle of water.

This is a good option, especially for ultra-endurance events like marathon runs, where your body can lose a lot of sodium

Oral Rehydration Solution

More severe dehydration requires more than just water and needs oral rehydration fluids. These allow the body to nourish itself with the essential nutrients it lacks from water, such as magnesium and calcium. This is an effective way to rehydrate fast, especially when losing a lot of fluid. 

If you don’t have these powdered products at home, you can also make your own oral rehydration fluid with the following: 

  • 1 liter of water
  • 6 teaspoons of sugar
  • 1/2 teaspoon of salt

Stir these until dissolved, and you’ve created your own rehydration formula. While it may not contain the same electrolytes as other products, it provides your body with essential nutrients that it loses when dehydrated.

When dehydrated, your body can lose significant amounts of sodium and glucose, so it’s important to rehydrate with a healthy dose of sodium and glucose in your water. 

Skim Milk

Skim or low-fat milk can be a great option to rehydrate. Like sports drinks, milk naturally contains electrolytes and balances the amount of water in your body.

After a high-intensity workout, a glass of milk with a nutritious meal can provide your body with the essential nutrients it’s missing and rebuild. 

This isn’t the best option for everyone, though. If milk and milk products cause you stomach discomfort or you are lactose intolerant, avoid drinking milk as a way to stay hydrated.

Instead, plain water or adding electrolytes to your water can be your best option. Remember that after intense workouts, your body needs to rebuild any lost nutrients and muscle mass, so staying hydrated is so important. 


If you need a rehydration solution for outside events this summer, consider a Quench Buggy for your next outdoor event. From small events to large outdoor festivals, we have a water trailer that suits your needs, helping your community keep up with their water intake.

From our small Quench Solo to the Original Quench Buggy, these water trailers can be delivered to wherever your event takes place, and most importantly, ensure everyone stays hydrated throughout the day. Check out our available models here.