Hydration packs – on your back, waist, or in your hand?

Last updated: 22-Oct-18

By Ian Corless

With temperatures rising and longer lighter days for many of us in Europe and North America, we can hopefully all get out and run more. But as we all know, or maybe we don’t, we need to consider several things when running in the heat:

  • It’s harder
  • You sweat more
  • You need more fluid

We need to adapt. So what happens when the mercury rises?

Question, do you prefer it:

  •  On your back?
  •  In your hand?
  •  Around your waist?

Of course I am talking about your method of hydration.

Our core temperature rises with exercise. In simple terms the more we exercise, or the harder we exercise the more the core temperature rises.

Our clever body reduces this core temperature by evaporation (sweat). Sweating reduces the body’s core temperature and hopefully will allow us to continue exercise at the pace that we wish to run at.

I say hopefully because the process of evaporation means that we lose liquid (hydration). The more we sweat, the greater the risk of dehydration and therefore we need to rehydrate.

“Your body needs fluids for various functions. Body cells and tissues are filled with fluid, the nervous system requires fluid and the fluid component of your blood (known as plasma) is also affected by your drinking habits. Exercise leads to a loss of body fluids via sweating and breathing and this loss of fluid can eventually lead to what is commonly termed dehydration.” – Marc Laithwaite

Dehydration increases heart rate and also adds to core temperature rises. It therefore can become a vicious circle. Initially running will feel much harder, the supply of oxygen to the brain will become impeded as blood is forced to the skins surface to help reduce the internal pressure. Your muscles may start to fail, become heavy and cramp. We have all been there, yes?

Depending on external temperatures, ones ability to withstand heat and ones own personal sweat rate, it is possible to lose many litres of fluid in an hour when running. Marathon des Sables provides a great example.

So, if youre looking to perform or if you just want an enjoyable stress free run in the heat, you need to keep on top of hydration.

Importantly, hydration is NOT just fluid. Sweating means that we lose key minerals. These minerals keep our body in balance. Replacing electrolytes (salt/ sodium) to keep our body in balance is a key element that we all must look at.

“When you take a drink of water it reaches your stomach and waits excitedly to pass through the wall into your blood stream. Your blood is saltier than the water in your stomach and due to the higher level of salt in the blood, the water is drawn from the stomach, through the wall and into the blood. This water effectively becomes blood plasma and travels around your body. If it finds muscle tissue which has a higher salt concentration, the magnetic pull of the salt within the muscle will draw the fluid from the blood into the muscle.” – Marc Laithwaite

Just as our own personal fluid requirements are different, our salt requirements will also differ and this will also depend on the distance you are running and what external temperatures are like.

Hydration Products

So take your time to work out what works for you. Plenty of hydration products are now available on the market and they all offer different methods and tastes. For example, Saltstick offers a really handy tablet that works well with bladders or bottles as it means you can keep your electrolyte supply separate and it also means that you can adjust your needs on the fly. However, Nuun (and other similar products) offer a very popular flavoured tablet that comes in a handy tube that again can be taken with you on training or racing and added to your liquid supply. Personally, I am a fan of keeping my salt tablets separate so that I can adjust on the go and supplement as required. The Marathon des Sables organisers, for example, provide some very clear and specific advice and recommendations on how to supplement salt and in what quantities.

How do you avoid the dreaded dehydration?

First and foremost one must assess oneself and ones abilities. If you live in a hot climate with all year sun and heat you are going to be well adjusted. If you live in a more temperate climate and then suddenly get a heat wave, you are not going to be adjusted. It’s a simple fact that many fail to acknowledge. Running 8 min miles in 10 degrees is much easier than running 8 min miles in 25 degrees. As I said previously, if you try to run the same pace in much hotter temperatures only one thing will happen; your core will rise, you will sweat more, you will start to suffer and eventually you will come to a stand still if you don’t understand your body’s needs and requirements.

Top Tips to avoid dehydration

Slowing down in hotter climates (until adapted and trained) is inevitable. Accept that the warmer temperatures will mean a slower pace. This will allow you to regulate your temperature and keep on top of your hydration. The longer you spend in the heat, the more you will adjust and eventually you will start to be able to lift the pace for the same effort and sweat rate. In simple terms this is what pro athletes do when they ‘acclimatize’.

Do a self-check when running:

  • Do you feel cool?
  • Do you feel clammy?
  • Have you stopped sweating?
  • Do you feel sick?
  • Are you dizzy?
  • Are you fatigued?
  • Is your heart rate pounding?

Any of the above and you are starting to show signs of dehydration.

  • Reduce your pace to a walk, let your temperature drop and slowly rehydrate – don’t gulp.
  • Stop. Sit down in the shade. Recover and let your temperature drop while drinking slowly to rehydrate.
  • If you have all or a combination of the above symptoms your best option may well be to stop and recover. Come back another day with lessons learnt.

Recovery is key and it is important to rehydrate post training and racing but be sensible!

Hyponatremia (Excessive dilution of body salts)

Drink sensibly, don’t force yourself with water. Research into Hyponatremia has shown that drinking too much liquid (drowning from the inside) is what leads to this dangerous issue.

Here is an example:

  1. Take 1 medium sized bowl, add a tea spoon of salt and then add 1 pint of water and you have a salt solution.
  2. Add another pint of pure water and you have now diluted the salt solution.
  3. Add another pint of pure water and dilute the salt even further.
  4. Keep going until the salt solution is so weak you can hardly even taste the salt.

Be sensible, drink to thirst and not excess and all will be okay.

Drinking methods when running?

Do you prefer it on your back or in your hand? Or maybe you need both hands, or you prefer it all centred around your waist?

How we carry our fluid is a very personal choice and it also depends on the demands of the training or the race. If you are racing you may need to carry compulsory equipment and this will almost certainly mean a waist pack or a backpack is required.

But how we carry the liquid is what counts. The fluid needs to be accessible at all times as this will promote drinking.

Bladder? Bottles?

Bladder versus Bottles


Bladders come in varying sizes. 1ltr to 3ltr, with different methods of distributing the liquid to the runner, ultimately this is a pipe with a mouth valve.


  • Bladders sit on your back or around the waist.
  • They offer a slurp system that is easy to use.


The main issues with them are:

  • they are difficult to clean,
  • you are never quite sure how much you have left,
  • they are more awkward to fill when racing.


Like bladders they come in varying sizes but 500ml to 1ltr is normal. The size of the bottle may very well depend on your carrying system. For example – handheld bottles, bottles in a waist pack, bottles on a rucksack (at the back) or bottles on a rucksack (at the front).


  • Bottles are easy to fill on the go,
  • easy to clean,
  • cheap to replace.

Combination hydration packs

Manufacturers realize now that runners’ needs are increasing and runners are becoming more demanding. Therefore, packs such as the Salomon S-Lab 12 has allowances for a bladder on the back, bottles on the front and even two large ‘dump’ pockets on the side of the pack that will take bottles.


The advantages here are excellent as you can customize your needs for each run.

Putting it into practice

It’s not rocket science but not putting it into practice is the difference between a great run and a lousy run. More importantly, when racing, it is the difference between potentially winning and not even finishing.


Choose your method and keep hydrated on your next run!

"The longer you spend in the heat, the more you will adjust and eventually you will start to be able to lift the pace for the same effort and sweat rate"

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