How To Stay Hydrated Before, After And During Your Run

As the weather heats up, dehydration might be a risk- even on shorter runs. Here's everything you need to know on why hydration is important, possible signs of dehydration, plus a detailed guide to sports drinks. 

Why's Hydration Important?

Staying well hydrated is key for keeping your body functioning properly, not to mention keeping you at the top of your running game. This is especially important in summer because we lose most of our water through sweat, which takes the heat with it as it evaporates, helping us to cool down. 


Dehydration may occur in both dry and humid conditions. Heavy humidity reduces the ability for our sweat to evaporate, as the air is already saturated with moisture. This leaves you feeling hot, sweaty and needing to slow down. 


If the air is dry, the sweat evaporates more quickly, almost as you're producing it, so you're more likely to become dehydrated and put your heart under strain. This is because dehydration causes a decrease in blood volume, which in turn causes your heart to beat faster to pump blood around your body. 


The heat and the sun also increase your body temperature, which makes running more challenging. 


Even if you're properly hydrated, it's normal for your pace to slow down as your internal temperature rises.  

What's Dehydration?

Although rare, not drinking enough in the heat could cause symptoms of dehydration. Some of the signs could feel like fatigue, headaches, dizziness and decreased coordination. So, ensure you're drinking enough fluids before, during, and after your run. 



A Runner's Guide To Sports Drinks

Plain water often passes through the body too quickly and don't contain the necessary sugars needed to start your recovery process. This is where sports drinks come in. 


Most energy drinks contain a combination of quick and slow releasing sugars to provide both fast acting and sustained energy, as well as high amounts of electrolytes such as sodium, chloride and potassium to help replenish what you lose. 


Choosing the right sports drink to maintain the best hydration and electrolyte levels during a run can be tricky, as it depends on whether your're rehydrating or replenishing your energy before, during or after your run. 


Sports drinks are split into three categories. The one you choose depends on your activity and rehydration needs.



Isotonic sports drinks are most similar to the human body as they have a similar concentration of electrolytes and carbohydrates, so they rehydrate and reenergise quickly. They typically contain 6-8% carbohydrates, which is good for replenishing your energy levels. As a general rule of thumb, the higher the carbohydrate content the slower the absorption rate into your body. Isotonic drinks have a medium absorption rate, taken up by the body as quickly as water but with added energy. 


Isotonics are the most common sports drinks on the market.They're ideal for shorter duration and high-intensity exercise where energy levels are more important than rehydration. 


  • Electrolytes: Medium
  • Carbohydrates: 6-8%
  • Ideal use: Re-energise (before and during)


Hypotonic drinks have a lower concentration of carbohydrates than the blood but have the highest levels of electrolytes. This means they tend to be absorbed by the body the fastest so they're ideal for rehydration, but not for replenishing energy levels. Their main aim is to replace the water and electrolytes you lose via your sweat. 


This is ideal if you are running in hot conditions or a challenging race where rehydration is paramount. 


  • Electrolytes: High
  • Carbohydrates: >6%
  • Ideal use: Rehydration (during)


Hypertonic drinks are more concentrated in energy than your blood. They contain the highest amount of calories as they average 8% or higher carbohydrate concentration, making them ideal for refuelling and recovering after exercise. As they have a higher carbohydrate level, they have the lowest absorption rate, so shouldn't be used during runs as you're more likely to become fatigued once the energy wears off. 


Water, isotonic or hypotonic sports drinks don't contain enough sugar or electrolytes your body needs to recover from a strenuous run or workout, and as they're absorbed more quickly they pose a higher risk of oversaturating your body with water. The best recovery drink for a long run is a hypertonic drink with a 4:1 ratio of carbohydrate to protein. 


  • Electrolytes: High
  • Carbohydrates: 8%<
  • Ideal use: Recovery (after)

Hydration Top Tips:



1. Water Bladder

Depending on the length of your run you should probably carry some water with you, especially in hotter weather where you are more likely to overheat and get dehydrated. If you're running outside for a long period of time, then a water bladder is ideal and will easily fit into a running backpack. If you're in the gym, a water bottle will be easier as many machines have a water bottle holder (and you probably won't be wearing a backpack on the treadmill). 


2. Electrolytes: This might sound counterintuitive but you need more than water to stay hydrated. When you sweat you lose electrolytes, as well as energy, which can put stress on your body. There is now a huge range of hydration tabs that can rehydrate you with essential electrolytes. 


3. Listen to your body: This might sound like obvious advice but if your body is telling you to slow down or stop then do it. In hotter weather, your body will be put under increased stress from dehydration and increased temperatures, so listening to it when it starts exhibiting symptoms of dehydration is really important. If you start exhibiting symptoms of dehydration be sure to hydrate and keep an eye on your intensity. 


You May Also Like:

Let us know you agree to cookies

We use marketing, analytical and functional cookies as well as similar technologies to give you the best experience. Third parties, including social media platforms, often place tracking cookies on our site to show you personalised adverts outside of our website. We store your cookie preferences for two years and you can edit your preferences via ‘manage cookies’ or through the cookie policy at the bottom of every page. For more information, please see our cookie policy.