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A Drink In Time, Saves Time

Are you a good drinker when racing, or do you try to hold out until it's finished?  The difference between the two can sometimes make 'the difference'.  One would imagine that drinking enough during exercise would be a simple task; well it's not as easy as you think!

Voluntary dehydration is not a term that most athletes have come across; to explain it, it simply means that although you know that during and after racing - or hard training - you should drink plenty, you often can't be bothered, which usually means that apart from a few good mouthfuls you don't make the effort to drink copiously.

Even when athletes have been weighed before and after intense exercise and shown that they have lost a particular amount of fluid, they still find it difficult to completely replenish their loss.

All the sports nutritionists agree that race performance can be seriously affected by the loss of body fluid; in fact they can even tabulate the percentage loss of performance against a certain percentage loss of body fluid.  For example, during events such as the 10K, 1% bodyweight loss through dehydration would result in a 2% decrease in pace.  For those with a PB of 30-35 minutes, it would reduce their performance by around 30-40 seconds.  More extreme levels of dehydration - say the Wasdale fell race in July without drink - could create around 7% loss of bodyweight, this could create even more dire consequences, drastically affecting co-ordination and reducing performance by over 30%.  A big bonk can add a couple of hours to your normal race time.

So why do we need to keep the fluid level as near to status quo as possible?  Mainly because of the reduction in blood volume that accompanies dehydration.  During exercise, a good blood flow to the working muscles is needed to provide oxygen and glycogen for fuel and - especially if it is warm or humid - a good blood flow to the skin is required for cooling.  However, as blood volume drops due to loss of water from sweating, heart rate rises to maintain blood flow to the muscles.  This means the athlete has reduced economy and generally less tolerance to exercise.  At the same time, blood flow to the skin is reduced, because it's more important to maintain circulatory blood volume.  Thus cooling is impaired and body temperature rises.  This increased body temperature may also contribute to the weary feeling during endurance exercise in the heat and can even be dangerous if dehydration is severe.

Some athletes can lose more than two quarts of sweat every hour, which equates to about 4lbs an hour weight loss (about a stone at Wasdale if you don't drink!!)

So with all this evidence why do we not drink enough to compensate for the loss?  Again the boffins come up with more jargon, this time 'physiological inhibition'.  It seems that this occurs after moistening the mouth with a drink; as soon as the first sips of a drink moisten our mouths nerves in the mouth send signals to the brain to reduce our sense of thirst.  Then there is the reaction to that uncomfortable feeling that one has of fluid swilling around in the stomach.  Not having a drink to hand is another reason, plus at that particular time - when you are feeling a little jaded - you just can't be bothered to get one.  Think back to the end of a tough race when you are propped up against a wall feeling a little sorry for yourself, hoping someone will offer you a nice cool drink!  Plus, is the drink you get the drink you want to consume in quantity?  I certainly remember very clearly after a particularly tough Borrowdale leaning back against the big tent with a pint of lager that had no trouble in going down!

Many runners who on a warm day doing a long race, fade unnecessarily at the back end of the race, do so not because they were not fit enough, but because their body mechanisms had started to close down due to a loss of fluid.

It would appear that this inhibition is peculiar to humans; when cats and dogs become dehydrated during activity in hot weather and are given the opportunity to drink, they will usually rapidly drink back all the water they have lost and then stop drinking.  The drinking behaviour of human beings, however, seems much more complicated.  In fact, during exercise many athletes seem to avoid drinking, even though they know that re-hydration is likely to improve their performance.

Experience shows that if cold palatable drinks are within arm's length of well trained, experienced, exercising athletes most do drink enough to offset sweat losses.  However, if they have to move even a short distance to get a drinks bottle, voluntary dehydration usually occurs - which indicates to the sports scientists that a complex behavioural component is involved in determining fluid consumption by exercising athletes.

So, what can you do to beat this complex behavioural component?  The first thing is to recognise that it exists and that topping up with a drink to replace lost body fluids is not an easy exercise, so you know now that you have a challenge, your body needs the fluid but it gives you little encouragement to consume all that you require.

Availability is a key factor; the Ennerdale race taught me many hard lessons, one being that there can be a serious lack of water over the last third of the race (it was the first race where I learned to beg from passing walkers!)  What a difference it made if you went up a few days before the race and put a bottle out just after Haycock - or had some support - it made all the difference.

Having support during and after a race can be crucial in overcoming voluntary dehydration.

The type of drink, its flavour and temperature are other important factors.  Giving someone 15 litres of orange juice on their Bob Graham is not helpful - unless they really really like it!  However, the very thought of a cold pint at the end of a race has kept many runners going for much longer than may have been possible.

Another factor is that drinking on the run is awkward and needs to be practised; for my part I perfected the 'Squish' technique.  On long races I would carry the optimum number of small plastic bags with a couple of heaped spoonfuls of carbo-powder in.  These would be opened just seconds before the nominated stream and dipped into the water as I passed by, picking up about 8 - 10 fl oz.  I would run for about 50 metres or so - allowing the powder to mix well - before doing the 'Squish'.  This involved squeezing together the neck of the bag in one hand and poking the index finger of the other hand in the top of the bag to make a neat opening, The bag was then put to the mouth making a seal and the contents squeezed quickly - downing the lot in one go - with a Squish! (making sure to put the empty bag back in the bum bag, before anyone asks).  Taking drinks regularly when racing the fells is the key; even if you don't feel like a drink, never pass by a 'good looking' stream.  If there are no streams available, it's support time, or carrying time.

So can runners learn to drink more? - A top nutritionist states:
Athletes can be trained to drink more fluids, but whether or not most of them can be trained to drink enough during exercise to replace all fluids lost in sweat is questionable.  Still, I think we make a mistake if we think of voluntary dehydration as an insurmountable physiological barrier, because it isn't.  Individuals who understand the value of drinking, who have practiced drinking and are comfortable doing so, and most importantly, who have easy access to palatable fluids, can replenish all or almost all of their sweat losses during exercise.

In fact, sports scientists believe that minimising dehydration by drinking during exercise has the largest beneficial effect on performance of any single nutritional intervention.

So there you have it, the simple drink may never be thought about in the same light again, there's a lot more to fluid loss and energy depletion that most of us think.  Perhaps this summer when you have been out on the fells for a few hours without a drink and start to feel the energy drain, just think what a planned drink would have done for your performance.

Norman Matthews 2001-2004
Head Senior Coach
Horwich RMI Harriers