The Power of Hydration - Strategies for Athletes

The Power of Hydration - Strategies for Athletes

A study in 2016 on 400 male and female amateur athletes found that 31% of them turned up to training dehydrated. Many of us don’t have a hydration strategy or think enough about the impact hydration has on our training performance. 

How to Hydrate

Hydration needs will be individual (and are largely genetic), based on how much you sweat and your sweat sodium concentration, how salty your sweat is. 

We have an innate drive to drink to survive. Relying on your instincts is a good place to start; drink good fluids when you need to, water not caffeinated drinks. We need to be more proactive when training volume increases, your sessions are longer, or you train twice a day. Your hydration instincts won’t prepare you or recover you well enough. 

When we hydrate we want to absorb the water into the bloodstream and cells, not just consume it. Drinks with electrolytes in (mainly sodium) can help us maintain better fluid balance in the body than plain water.  The sodium will help your body retain more of that fluid so you don’t pee it out. This is better for your blood volume and ultimately training performance. 

The first step is to get to know your body, how it responds to fluid and training, and take note of what happens. Hydration strategies can emerge from this.

Advice For Training


  • <90 mins session, best to hydrate intuitively with water or a weak electrolyte drink. Important to start the session well hydrated. 

  • 90 mins to 3 hours, a hydration strategy will be important for replacement of fluids during training. 

  • 3 hours plus, vital to have a hydration strategy. This is especially true for endurance activities. 

  • Remember to consider the environmental conditions - if cold, sweat rates will be lower, if hot, sweat rates will be higher.


  • Well hydrated before you start training, otherwise performance and recovery will be negatively impacted.

  • Drink 45 mins before training to ensure the body has time to get fluid into the blood. 

  • For everyday training activities you’ll want to drink to thirst, try not to over do it! 

  • Pre-load with water or water with electrolytes, particularly sodium. 

  • Don’t drink plain water excessively before training, it leads to more trips to the loo as your body tries to avoid excessive dilution of blood sodium levels.

  • Training in the heat - strong evidence that taking in additional sodium with fluids before you start sweating improves your endurance.

  • Competition tip - leading up to the event take in a few more glasses of water. Could add some extra salt on your food to boost sodium levels and include a strong dose electrolyte drink before you start the competition. 


  • Drinking during training is mainly about preservation of blood volume, to counteract sweating. 

  • It helps keep the blood pumping to the muscles to fuel performance.

  • General advice is to drink to thirst during training. 

  • As you sweat more, your heart rate will start to rise as sodium levels decrease. 


  • Continue to drink to thirst. 

  • If you’re a heavy sweater you may need to consume more water to rehydrate. 

  • If you have high sweat sodium concentration, top up sodium levels either through food or drink.

Generally we want to act on instinct and on data. We don’t need to have an entirely structured approach to our hydration but as athletes, we don’t want to wing it. Practise sensible control but don’t over control. Understand and read your body’s cues and know what’s worked in the past.

Hydration and Electrolytes 

  • Large amounts of water in a small amount of time doesn’t hydrate you that well. If you push too much water too quickly, you’ll end up filtering that water out very quickly by weeing, as your body will try to preserve its levels of sodium. 

  • Drink water with a strong electrolyte solution to absorb the sodium into the bloodstream with the fluids. You then retain that hydration, which boosts blood volume levels. You will then need to drink less during the training activity. 

  • Amount of sodium to avoid upset stomach; studies have shown around 1,500mg per litre for pre loading drinks to be effective. 

  • Just because your urine is clear doesn’t mean you’re well hydrated. It can indicate that, but where it can go wrong is if you over drink. Clear urine all the time will mean you’re flushing electrolytes out of your system. Reduce the volume of fluid a little and put some electrolytes in to enable the body to rebalance itself better.

The Effects of Dehydration and Over-hydration

1-5% loss in body fluid (in comparison to body weight) will result in a decrease in performance. The main reason performance drops is due to a reduction in blood volume. This is particularly problematic in long hot events, for those who have high sweat rates, or those who are newer to training. 

If you start a session well hydrated, being dehydrated by the end will have less impact on you and your performance. Being dehydrated impacts cognition, reaction, and speed. Our quality of sleep will also be impacted. 

If we drink too much we dilute our blood, and the blood sodium level will drop. This combined with a lot of sweating can lead to hyponatremia. This is when fluid shifts from the bloodstream to our cells to protect the level of sodium in our body. This makes cells swell up and common signs can be puffy fingers and ankles. It’s a serious problem when it moves into the brain. This can often be misdiagnosed as dehydration as athletes commonly collapse during long events.