Water is the only drink for a wise man – Henry David Thoreau

Unlike the camel, we can’t go weeks without water.

So water is important. It makes up 60 percent of your total body weight and carries out many essential functions in your body.

When you exercise, you lose water through your sweat. So you need to put some back in. All straightforward so far.

I’d be the first to admit though that I don’t understand how much I should be drinking when exercising. It seems to be a delicate balance between avoiding the need to take a wee every few minutes and dying of thirst. And it’s one I never seem to quite get right.

Cool, clear water

I’ve suffered from those pounding headaches and/or crippling cramps when running or cycling because I haven’t drunk enough. And as for the question of whether I should stick to water or mix it up with energy drinks and which ones – well that’s a whole can of electrolytes in itself.

Everyone has their own take on it and there’s an awful lot of confusing advice out there. The waters are muddy (pardon the pun) to say the least. So let’s stir them up and see what we can sift out.

First off – how do I know I’m dehydrated?

This is an easy one. The accepted advice is to check the colour of your urine. Pale yellow coloured wee is good. The darker it is the more poorly hydrated you are and you need to be drinking more water. Tea, coffee, caffeinated soft drinks and alcohol all have a dehydrating effect so are NOT the answer to rehydrating. Sorry to pour cold water on that.

How much should I be drinking?

Looking for advice the National Hydration Council seems like a sensible place to start. This is a not for profit organisation with the aim of research and promoting facts about hydration.

So what do they say?

Well, the starting point is the European Food Safety Authority’srecommendation. This states that men should consume 2.5 litres per day and women 2.0 litres via food and drink. Of course, this assumes a normal day without any significant exercising.

What about when I am exercising?

Hmmm. This is where the muddy waters become a maelstrom. The National Hydration Council says that the amount you need to drink when exercising will vary depending on the individual. So far so vague. What we need is some specific guidance.

I turned to Runners World and British Cycling to see if they could shed any further light.

Before exercise

The general advice seems to be to drink around 500-750ml at least two hours before exercising. If you’re dehydrated when you start your performance will be affected, so you want to start off on the right track.

As Runner’s World points out: you keep cool by sweating, so replacing fluids is essential to prevent your blood from thickening and reducing your heart’s efficiency.

During Exercise

Much is going to depend on the duration and intensity of the exercise.

Moderate dehydration is not unusual when running. Elite runners would struggle to remain hydrated during a race.

If you want to get scientific about it you can try weighing yourself before and after exercise (say 60 minutes’ worth) to see how much fluid you’ve lost. You need to remember to strip off each time and go for a wee before you weigh yourself at the start. I can imagine this isn’t for everyone though!

But is there any consistent advice on how much of the fluid lost during exercise you need to replace?

Runners World cite a study by the University of Aberdeen. The report states that by replacing at least 80 percent of the fluid lost, or keeping within 1 percent of your body weight, performance is not affected.

But everyone is different and every exercise is different. And as for the weather well that can be wildly different as well!

Runners World report that:

current guidelines recommend drinking anything from 300ml to 800ml of fluids per hour when you’re exercising. As we’ve already stated, the upper end of that scale is almost certainly more than you need. However, you need to try different approaches to hydration in your training to establish a strategy that works for you and remember: you’re an experiment of one.

Water or energy drinks?

British Cycling say that, if you’re exercising for less than one hour then water alone should be adequate.

For longer periods of exercise you should consider including something with carbohydrates and electrolytes. This could be a sports drink. Electrolytes are salts that include sodium, potassium, calcium and magnesium. We lose these when we sweat and they have to be replaced for normal cell function.

Sports drinks often contain a blend of simple sugars, including glucose, fructose and sucrose. These give a quick release of energy together with more complex carbohydrates such as maltodextrin to provide long-term energy.

If exercising for longer periods you’ll need to take on both. Sports drinks all differ a little so it’s best to try a few out and see what works best for you.

Hypotronic, Hypertronic? Let’s call the whole thing off

You may have come across the terms isotonic, hypotonic and hypertonic but what does it all mean?

A hypotronic drink is more dilute than your body fluids. Thus, it has a faster absorption rate than plain water.

Isotonic drinks have the same concentration of electrolytes and minerals as your body’s fluids. So they too are absorbed as fast or faster than water.

They provide a good balance between rehydration and refuelling. Lucozade Sport or a fifty-fifty mix of fruit juice and water are good examples of isotonic drinks,

Hypertronic drinks, such as coke, lemonade and fruit juice are more concentrated than your body’s fluids. So their absorption rate is slower. Hypertonic drinks slow the speed of fluid replacement as they reduce the rate that the stomach empties.

Many long-distance runners swear by coke towards the end of the race. The caffeine combined with sugar can give some runners a boost and settle the stomach. Probably one to experiment with though if you haven’t tried it before.

Bottles or Hydration Packs?

There are two ways you can carry your fluid when running or cycling. Much of this comes down to personal preference.

Hydration packs with water bladders allow you to carry substantial quantities of water with reasonable ease so you don’t need to worry about refilling.

They come in different shapes and sizes so you’ll need to find one that’s right for you and your activity.  Some people find it cumbersome and uncomfortable carrying something on their back when exercising.

For runners, carrying bottles can be more difficult although waist belts for carrying bottles are available as an alternative.

For longer distances, I’d struggle to carry enough water in bottles when running. For cyclists, bottles are a good option as they can be held on the bike.  Combined with a hydration pack the cyclist can stay hydrated with ease.

 And finally…

While there are some helpful guidelines out there as to how much and what you should drink when exercising my overall advice would be:

Experiment. Experiment. Experiment.

Find out what works for you during your training runs/rides and adapt and adjust things accordingly.

Look out for further posts coming soon on hydration packs and how best to use them.