How To Hydrate Fast? 4 Ways To Rehydrate Quickly

If you’re even slightly dehydrated, you likely won’t feel your best. In this article, we’ll be covering strategies for how to rehydrate fast – whether it’s after a tough workout, an illness, or just because it’s hot out. Let’s get into it!

Hydration – Why is it So Important?

With up to 60% of the human body being made up of water, it makes sense that regularly hydrating is important for our survival. Humans wouldn’t be able to survive for much longer than a few days without it. 

Hydration is crucial for overall bodily function, including the protection of organs, regulation of temperature, maintaining electrolyte balance, and removing waste products. For athletes, hydration is also especially important when it comes to performance, recovery, and injury prevention. So, for any athlete, prioritizing hydration should be a top priority. 

Below we’ll be going over how you can tell if you’re dehydrated, and what you can do about it. 

Signs of Dehydration

There are a few key signs of dehydration to look for that should tell you it’s time to drink some water. 

First, and foremost, if you’re thirsty, you’re likely slightly dehydrated and should drink some water. This sensation is your body’s way of telling you this, and will typically be accompanied by a dry mouth. Less frequent and darker urination are also key signs that you haven’t been drinking enough water.

Letting thirst build-up can lead to more serious negative side effects including:

• Headaches
• Dizziness
• Tiredness & Fatigue

These are all symptoms associated with relatively mild dehydration, and can typically be resolved through simply drinking water. More severe dehydration can lead to symptoms such as:

• Rapid heartbeat and breathing
• Confusion
• Fainting

Any symptoms of severe dehydration should not be ignored and should be addressed with immediate medical attention. 

4 Strategies for Rapid Hydration

Most cases of mild dehydration can be solved by simply drinking water or sports drinks. However, more moderate to severe cases of dehydration will require oral rehydration solutions or even intravenous fluids. Below we’ll be going in-depth on each of these strategies for rehydration, and when they’re typically necessary. 

✅ Drinking Water

First and foremost, drinking water is the best way to rehydrate fast in cases of mild dehydration. If you’re experiencing an increased thirst drive, simply drink enough water to satiate your thirst. 

How much water everyone needs to drink a day is fairly individualized, but The National Academy of Medicine recommends that adult men drink ~13 cups a day, and adult women drink ~9 cups a day.

Breaking this down by weight, it comes down to 40ml/kg of body weight. Regularly drinking significantly less than this may lead to dehydration, so upping your water intake is a great way to prevent any unwanted side effects. 

It’s worth noting that for more severe cases of dehydration, simply drinking more water may not be enough. In these cases, we recommend seeking medical attention immediately for more rapid rehydration. Cases of severe dehydration may be treated with a combination of ORS and IV rehydration, which we’ll be covering in more depth below. 

✅ Sport Electrolyte Drinks

A common alternative to water for many athletes is sports electrolyte drinks. These typically combine electrolytes (sodium, potassium, magnesium, etc.) and simple carbohydrates to make a drink that provides both hydration and quick energy.

While water will generally be just as effective for most people, drinks with electrolytes may be beneficial if you’ve lost a lot of water through sweat. 

We mainly recommend electrolyte drinks for endurance athletes who tend to train for several hours at a time. These athletes lose significant amounts of electrolytes and fluids through sweat, making electrolytes beneficial when rehydrating.

Ultra-endurance athletes in particular are at risk of hyponatremia/overhydration where the balance of water and electrolytes is thrown off. This can lead to serious health complications. 

To ensure adequate rehydration in these cases, the AIS recommends having 0.5-0.7g of sodium/L of fluid during endurance training. This will help prevent hyponatremia, while still preserving thirst drive and the palatability of fluids. Replenishing with electrolytes will likely also be beneficial post-workout. 

✅ Oral Rehydration Solutions (ORS)

Oral rehydration solutions are typically used to rehydrate both children and adults losing significant amounts of fluid caused by diarrhea or vomiting. This is likely the fastest way to hydrate at home in cases of moderate dehydration.

ORS are often used alongside intravenous hydration solutions in cases of severe dehydration, although moderate dehydration can often be treated entirely with ORS. 

ORS are typically made up of:

• Water
• Electrolytes/Salts
• Carbohydrates/Sugar

While they have a similar basic formula to sports drinks, they contain less sugar which could end up worsening symptoms like diarrhea. 

Overall, while ORS are effective for rapid rehydration, they are mainly reserved for those with illnesses causing dehydration, or those with general symptoms of moderate to severe dehydration. While ORS can be used in milder cases as well, it’s likely unnecessary.

✅ Intravenous (IV) Fluids

Finally, in cases of severe dehydration, intravenous fluids may be necessary. This is when fluids are injected into a vein, and are a common treatment for serious cases of dehydration – whether it’s caused by illness, injury, exercise, or heat. Similar to ORS and Sports Drinks, IV fluids are typically made up of water, electrolytes, and sugar. 

As mentioned, IV fluids will commonly be accompanied by ORS to speed up rehydration even more. IV fluids work quickly and can be a major difference-maker in patients who are severely dehydrated or seriously ill.  

3 Hydration Tips for Different Situations

As you can see, numerous rehydration solutions can be reserved for different situations. Below we’ll be going over 3 common scenarios where you may need to rehydrate, and discussing which solution is best. 

1. Post-Exercise

First, it’s very common to feel mildly dehydrated after exercise. How you rehydrate will depend largely on the style and length of the exercise you perform. 

For moderate exercise lasting less than an hour or two, hydrating with water both during and after your workout should be fine. For more intense endurance exercise where you’re losing significant amounts of sweat, using an electrolyte or sports drink may be ideal, especially if exercise lasts for longer than two hours. 

2. Hydrating in Hot Weather

You should treat hydrating in hot weather similarly to how you treat hydrating post-exercise. 

If you’re simply out in the heat, doing fairly low-intensity exercise, simply drinking water should be fine. If you’re sweating a lot, or doing moderate to intense exercise, a sports drink or electrolyte supplement may be beneficial, especially if you’re outside for an extended period. 

3. Rehydrating After Illness

After illness, it’s important to know what to drink to get hydrated fast to prevent any serious side effects. This depends largely on the severity of your illness, and whether it’s linked to dehydration. 

For mild to moderate sickness, drinking water or sports drinks to rehydrate should be enough. For illnesses that cause diarrhea or vomiting, ORS may be beneficial during the illness to fix dehydration fast.

Finally, for serious illnesses and severe dehydration, a combination of IV fluids and ORS may be ideal for quick rehydration. We always recommend seeking out and following a doctor’s advice in these scenarios!

4 Factors Affecting (Re)Hydration Speed

Hydration is often not as simple as just drinking a glass of water and becoming fully hydrated again. Several factors contribute to how fast you’ll feel hydrated again which we’ll be covering below. 

1. Volume and Rate of Fluid intake

Arguably most important to how quickly you feel hydrated is how much fluid you’re getting and how quickly you drink it. Drinking more water over a shorter period will likely lead to faster hydration. 

However, large volumes of water can stimulate diureses, so it will be better to keep a higher rate of fluid intake over the course of several hours, instead of chugging a bunch of water all at once. 

It’s also important to be aware of overhydration, especially in cases of endurance training. Be sure to consume adequate electrolytes alongside high quantities of water after losing large amounts of sweat. 

2. Solution – Electrolyte Balance

Similarly, drinking fluids that contain electrolytes will likely lead to quicker hydration than plain water, especially when the drink also includes carbohydrates.

Still, for the average person, it’s unlikely that extra electrolytes and carbohydrates will make a major difference in hydration. As a result, we still mainly recommend electrolyte drinks for those who have lost a significant amount of electrolytes through sweat. 

3. Gastric emptying

Gastric emptying is the process of the stomach being moved further through your digestive tract. Dehydration appears to lead to slower gastric emptying, which can lead to increased gastrointestinal disturbance. Because water is primarily absorbed in the small intestine, slower gastric emptying caused by dehydration may also lead to slower absorption of water. 

4. Monitoring Hydration Status

Regardless of the scenario and method of rehydration you’re using, monitoring hydration is important. 

Monitoring your thirst, the frequency and color of your urine, as well as any side effects of dehydration can be key indicators of how hydrated you are. Of course, in cases of severe dehydration, a doctor will likely be monitoring your hydration as well. 

Electrolytes we Recommend – Hydrate by Transparent Labs

Especially if you’re a serious endurance athlete, hydrating with electrolytes can be important for performance and avoiding overhydration. Even for average people, smaller doses can be beneficial for improving the flavor of water, and getting some extra electrolytes in. If you’re interested in electrolyte supplementation, we recommend Hydrate by Transparent Labs. 

This supplement contains 884mg total of electrolytes, with a high amount of sodium perfect for rehydration after endurance training. See the full electrolyte breakdown below: 

Electrolyte	Mg/Serving
Sodium	500mg
Potassium	250mg
Calcium	84mg
Magnesium	50mg

1 serving mixed with a liter of water will fall on the lower end of the AIS guidelines of 0.5-0.7g of sodium/L of water. Non-endurance athletes will want to consider using much less to improve the flavor and avoid consuming excessive amounts of sodium.

We don’t advise anybody use Transparent Labs’ recommended serving size of one full serving per 6-8oz of water. 

Hydrate contains no artificial ingredients, and comes in 6 different flavors. Each serving costs ~$1.33, making the price similar to or cheaper than most standard bottled sports drinks. This makes it a great hydration option, especially for serious endurance athletes. 

Conclusion

In most cases of mild dehydration, water will be sufficient to quickly rehydrate. After endurance exercise in particular, an electrolyte-rich sports drink may be a better option. And in the case of severe dehydration, ORS or IV fluids will likely be necessary. 

If you’re interested in a high-quality electrolyte supplement, we recommend Hydrate by Transparent Labs. 

Do you have any tips for how to get hydrated quickly? Let us know your thoughts in the comments below!

References:

1. Water Science School, “The Water in You: Water and the Human Body,” USGS, https://www.usgs.gov/special-topics/water-science-school/science/water-you-water-and-human-body#overview (Accessed Apr. 12, 2024). 
2. Rebecca Kranz, “Symptoms of dehydration: What they are and what to do if you experience them”, Harvard Health Publishing Harvard Medical School, https://www.health.harvard.edu/staying-healthy/symptoms-of-dehydration-what-they-are-and-what-to-do-if-you-experience-them (Accessed Apr. 12, 2024). 
3. Lawrence W. Judge, et. al, Hydration to Maximize Performance and Recovery: Knowledge, Attitudes, and Behaviors Among Collegiate Track and Field Throwers J Hum Kinet. Jul; 79: 111–122. (2021).
4. The Nutrition Source, “Water,” Harvard T.H. Chan School of Public Health, https://www.hsph.harvard.edu/nutritionsource/water/ (Accessed Apr. 12, 2024). 
5. Nicholas B. Tiller, et. al, “International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing,” Journal of the International Society of Sports Nutrition volume 16, Article number: 50 (2019).
6. AIS Sports Supplement Framework, “Electrolyte Replacement Supplements,” AIS, https://www.ais.gov.au/__data/assets/pdf_file/0020/1000487/36194_Sport-supplement-fact-sheets-electrolytes-v5.pdf (Accessed Apr. 12, 2024)
7. Centers for Disease Control and Prevention, “Rehydration Therapy” Centers for Disease Control and Prevention, https://www.cdc.gov/cholera/treatment/rehydration-therapy.html (Accessed Apr. 12, 2024)
8. Cleveland Clinic, “IV Fluids,” Cleveland Clinic, https://my.clevelandclinic.org/health/treatments/21635-iv-fluids (Accessed Apr. 12, 2024)
9. N J Rehrer, et. al, “Effects of dehydration on gastric emptying and gastrointestinal distress while running,” Med Sci Sports Exerc. Dec;22(6):790-5 (1990).
10. Photos made by Torokhtiy Media Team.