How to stay hydrated when you’re defying the darkness

In Fitness / Health, Outdoor, Tech / Gear, Performance

Hydration is always a big topic during the summer, when warmer weather leads to increased sweat rates, making it tough to stay hydrated if you're doing a high volume of training.

But, because we tend to wear more layers when training outside when it’s cold, dark and wet - and we’re generally exercising in colder, drier air - the need to pay attention to hydration doesn't just go away during the cooler months. So, we asked our friends at Precision Hydration to give us some advice on how to stay hydrated when you’re out defying the darkness in your Proviz gear…

Staying on top of your hydration all year round means you’ll ultimately perform better and get more out of each training session and that’ll pay dividends when whatever you're training for comes around.

So, here are some tips to help you stay hydrated and get the most out of your training sessions on those cold and dark mornings and nights…

Before longer sessions out in the cold

Because we have to fit training in around the rest of life, it's not unusual to start training sessions mildly dehydrated.

That’s not the end of the world for shorter/lighter workouts but, if you feel like you run the risk of starting any of your longer or more intense sessions dehydrated, drinking a 500ml (16oz) bottle of a stronger electrolyte drink (containing at least 1,000mg of sodium per litre) about 90 minutes before you start can really help you maintain your performance and get more out of your session. This is often referred to as ‘preloading’.

It’s important that it's a stronger electrolyte drink because the extra sodium in there helps your body absorb and hold onto fluid more effectively than if you just drink water (or a weaker sports drink). This makes more fluid available for your body to draw on when you start sweating.

To be clear, you don’t need to be preloading before every training session. In fact, most sessions don’t call for it. It’s more of a tactic for when you’ve not kept up good day-to-day hydration and you have a particularly long or intense session ahead of you where you’ll be sweating a lot and/or where taking fluids on board might be difficult.

Woman filling water bottle at PH station - Image credit

During longer sessions out in the cold

For your longer sessions outside in colder, drier air, you might find that you benefit from drinking an electrolyte drink as there’s a tendency for your body to want to pee more in the cold (a well documented, but not fully understood, phenomenon called 'cold diuresis’).

Despite the cooler temperatures, you may still be sweating quite a lot if you’re wearing extra (Proviz!) layers out and about, so holding on to more of the fluids you take in is important.

Adding more electrolytes (mainly sodium) to your water helps you to absorb and retain fluids more effectively. This helps maintain your blood sodium levels, which is crucial to maintaining performance. (Learn more about why sodium is crucial to performing at your best)

You might also consider drinking electrolyte drinks when you’re planning more than one workout on the same day. Any drinking you do in the first session of the day will help offset your sweat losses so that you stand more chance of starting session 2 fully hydrated and ready to perform at your best. 

After session

Even when drinking to thirst during training, you’ll often end up a little bit dehydrated by the time you finish. That’s ok as long as it’s not to a degree that negatively affected your performance.

In most circumstances, simply rehydrating and replenishing electrolytes through the food and drink you take in after training is fine.

But, there are times when you might benefit from a proactive approach to rehydration, such as...

  • when you’re doing another workout soon after the first one
  • when you’re aware you’ve sweated out a lot more than normal during a session
  • when you’re training late in the day and are going to bed soon after finishing, so won’t have much time to eat and drink afterwards

In these circumstances, drinking a 500ml (16oz) bottle of a stronger electrolyte drink like PH 1500 in the hours after you finish can be beneficial as research shows that drinks containing sodium enable better rehydration as it allows the body to hold onto more of the fluid. Asker Jeukendrup and Lindsay Baker (2014) concluded that if you want to rehydrate quickly, then you need to drink ~1.5x more fluid than you’ve lost - and you need to make sure there’s plenty of sodium either in or with the fluid to account for your salt losses too. 

Sarah Crowley sweating and drinking from PH bottle

But, don’t drink too much!

When following the guidelines above do be careful not to drink too much. In the past, when it came to hydration, 'more is better' was the standard advice.

It's actually more of a balancing act. Your body has developed fantastic mechanisms to help you maintain a fluid/electrolyte balance.

If you drink too much plain/weak fluid when sweating for prolonged periods, you risk further diluting your blood sodium levels and developing a condition called hyponatremia, which has some pretty nasty symptoms like nausea, vomiting etc.

Learning to listen to your body and to read the early signs of thirst is the best way to keep your fluid levels balanced and stay hydrated.

Andy Blow is a Sports Scientist with a BSc Honours degree in Sports and Exercise Science from the University of Bath. An expert in hydration, he has co-authored a number of scientific studies and books.

He was once the Team Sports Scientist for the Benetton and Renault Formula 1 teams and remains an adviser to the Porsche Human Performance Centre at Silverstone. 

Andy has finished in the top 10 of IRONMAN and IRONMAN 70.3 races, as well as winning an XTERRA Age Group World title. It was his own struggles with cramp that led to him specialising in hydration and founding Precision Hydration.