Do you really need to run with water?

Do I need to drink water while running? Here’s why you’re probably hydrated enough already

Posted by for Wellbeing

Are you worried you’ll get dehydrated if you go out running, particularly in warm weather? Well, if you’re doing a 5k, you probably don’t need to bring water with you – as writer and runner Anna Bartter has been finding out.

Hands up if you hate having to run while sweatily clutching a slippery water bottle. How about trying to drink from a paper cup during a Race for Life event or Run Through 5k? If you’re anything like me, you’ll find the whole running hydration situation quite stressful (soaked top, anyone?).

There’s no denying that hydration is an important consideration for runners, whether recreational or more seasoned. As the temperature starts to creep up (hello, May heatwave) you might be starting to wonder whether it’s time to dust off those ergonomic bottles and drink up on your runs. 

While there’s a plethora of research into endurance running and hydration, what’s the deal with drinking during your local Parkrun or quick lunchtime jog? 

“Hydration is highly individual but should be a consideration for all training runs,” explains ultra running coach Hannah Walsh. “I usually say to my athletes that if your run is under 60 minutes, you can get away without taking on any fluids during the session.”

It’s generally agreed that waiting until you feel thirsty isn’t recommended, and if you’re feeling parched while running, you’re probably already dehydrated. However, modest, temporary dehydration is normal for runners and is easily resolved by drinking once you’ve stopped moving.

“Beginners may want water from a psychological point of view, but with experience and as their running develops, they’ll become more confident and in-tune with their bodies,” explains running coach Rachael Bruford. And the more in-tune you are, the more you might realise that you’re not actually that thirsty when you’re out running.

Likewise, if you’re hitting a new trail run and might risk getting lost, it’s probably a good idea to have some water in case you end up out for longer than planned. Just make sure you’re not overdoing it. Bruford warns that “being over-hydrated poses more risk to runners than dehydration, which many people don’t realise”.

Why is hydration so important?

60% of the human adult body is water, so it’s keeping that liquid level topped up is essential for a range of vital bodily functions – from helping our digestive systems function properly to carrying glucose, oxygen and nutrients to cells.

When we exercise and our core body temperature rises, our bodies are designed to dump this additional heat so we can maintain a stable internal temperature. Your body does this by sweating – the process where a little of that water is carried to the skin via capillaries to cool us down. 

If this water isn’t replaced, we start to suffer. Even mild dehydration impairs not only performance, but also general health more widely, causing headaches, dizziness and poor concentration.

If you don’t drink enough fluid while exercising, your blood thickens, increasing your heart rate and reducing its efficiency. In short, you’ll feel more puffed, more quickly.

Studies show that just a 1% reduction in body weight through fluid loss whilst running equates to a dip in performance of 2%. In simple terms, you’re unlikely to hit that new PB if you’re not drinking enough. 

But how much we sweat and how we react to heat is individual and depends on several factors, including the temperature of the running environment and our unique physical make-up. So how can you tell if you need to hit that water station? 

Why you don’t need water if running for under an hour

As a rule, Bruford doesn’t hydrate on short runs: “Sometimes, before a short race, I might be nervous and I’ll get a dry mouth, but this doesn’t mean I’m thirsty: a quick swig of water is all I’ll need.”

The experts agree that the key is to be well-hydrated prior to running, but this doesn’t mean downing a pint of water as you head out of the door. In fact, drinking too much just before you go on a jog can cause abdominal cramps and general discomfort.

Hormones can impact your thirst, also, Walsh explains: “If you’re running in the high hormone phase or you’re menopausal, drinking to thirst isn’t as reliable.” 

“Remember that hydration isn’t just a case of swigging litres of water in one go,” Bruford reminds us. “It’s important to drink consistently and in sensible amounts; hydration is something that should be constant.”

Ideally, you should aim to consume up to 10ml of fluid per kg of bodyweight two hours before you run, according to Performance Physique running coach Arj Thiruchelvam. This might mean setting your alarm a little earlier than you’d like, although Walsh is an advocate of pre-hydrating: “Start to take onboard more fluids the night before a run, especially if you tend to run in the mornings.”

If you make hydration as much a part of your training regime as stretching and nutrition, the consensus is you should be safe to trot out without your water bottle on those shorter runs.

How to tell if you run is short enough to for-go the water

But what is a short run? This will vary from person to person. Bruford explains: “When thinking about hydration, think about time on your feet rather than distance, as some people can run an easy 5k in around 20 minutes whereas others may take 45 minutes or more.”

There are other factors to take into consideration too. Bruford says it’s important not to underestimate the impact of heatwaves, however mild. “If you’re not used to running in warmer weather or you’re running while on holiday, you may need to hydrate even on a shorter run.” 

As your core temperature rises, you’ll start to feel fatigued more quickly, so make sure you have a drink relatively nearby. The good news is that daily flat white can help; although caffeine is a mild diuretic, it’s generally accepted that the fluid provided by a cup of tea or coffee will still be beneficial overall. So go ahead, have that second cuppa before lacing up, but be aware that it may also have you running for the loo.

Runners can be at risk of over-hydration

Increasingly, experts believe that we are over-hydrated, which can lead to serious consequences. Hyponatremia occurs when sodium levels in the blood become dangerously diluted, resulting in nausea, vomiting, headaches and confusion. If left untreated, the condition can become life-threatening, and interestingly, is more common in women than men.

So, there you have it: nail your daily drinking and you’ll be running hands free all the way to your post-5k flat white.

For more hydration tips, visit the Strong Women Training Club.

Images: Getty

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