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Hydration for Runners

Running is great. It fills us with energy, builds our stamina, helps us lose weight, and elevates our mood.


But a good run depends on more than simply putting your running shoes on and heading out the door. One crucial piece of the equation is hydration.


So, with that in mind, let’s break down hydration, why we need it, and how to time it for optimal performance and well-being.


Why Considering Hydration for Runners Is Crucial For Performance And Wellness


Water makes up 60 percent of the adult human body (1). According to research, even a two percent dehydration can significantly impact athletic ability and cognitive function (2). The good news is, dehydrating ourselves isn’t that easy. But it’s still possible, and the process begins the minute you start running.


Under normal circumstances, your body loses water in three primary ways:


  • Urination
  • Sweat
  • Respiration


Assuming you don’t stop for bathroom breaks while running, you only have to worry about the other two: respiration and sweating.


We lose trace amounts of water while breathing and a bit more while doing so as we run. Still, the longer the run is, the more water we breathe out. But most runners need to worry about the water we lose through sweat.


As you begin to run, your core body temperature increases, which triggers your body’s natural cooling mechanism: sweating. Depending on how hot your training environment is and how much you typically sweat, you can lose small or large amounts of fluid (3). Sweat also leads to significant sodium losses – an electrolyte that plays a vital role in intra- and extracellular fluid balance (4).


Fluid loss is not good because it leads to dehydration which can bring several adverse effects (5):


  • Headaches
  • Brain fog
  • Lack of motivation
  • Fatigue
  • Muscle cramps
  • Dizziness


If you care about optimal performance and well-being, you don’t want to get dehydrated.


Hydration Timing For Optimal Performance And Well-Being


Your water needs depend on factors such as:


  • Age 
  • Sex
  • How much you sweat
  • Training environment temperature


General recommendations state that men should aim for 3 liters of water per day, and women should drink up to 2.2 liters – 101 and 74 ounces, respectively (6). But your needs could go up if you sweat a lot, so it’s essential to listen to your body and look for symptoms of dehydration.


Hydration for optimal performance means drinking enough water throughout the day and having some before, during, and after your run.


  • Pre-run: aim for at least 16 ounces of fluids an hour before your session to allow for optimal absorption
  • Intra-run: aim for 5 to 10 ounces of fluid for every twenty minutes of running
  • Post-run: drink at least 20 to 25 ounces of liquid, and don’t be afraid to consume even more if you sweat a lot


Final Words


We often seek the optimal training and nutritional strategies to optimize our performance. But more often than not, our hydration habits will have a much more significant impact, especially for long moderately-intense activities like running.


Proper hydration is crucial for endurance exercise because it affects energy levels, maintains cognitive function, optimizes athletic ability, and can prevent headaches.