Water, water everywhere, but how much should I drink?

Hydration

Hydrating during exercise has received a fair bit of attention of late, with controversy over what, when and how much you should or should not be drinking. A fairly simple truth though is that hydration does have an effect on both health and athletic performance. You just have to get the balance right.

Let’s take a look at some of the basics.

When we exercise our bodies generate heat. It’s essential that our temperature is regulated within a fairly narrow range, or we are at risk of heat injury – commonly known as heat stroke or heat exhaustion.

Heat injury is unpleasant, potentially dangerous and will certainly impair athletic performance.

But it can be avoided.

Sweating is the body’s primary method of cooling and our capacity to cool is therefore in part dependent on our level of hydration – if you don’t have the fluid to lose, your body can’t cool itself. And it’s for this reason that it’s important to maintain an adequate level of hydration when exercising, particularly in warm/hot environmental conditions.

Now, British summers tend to be a little unpredictable. Last year’s summer was rather wet and cold, but the top temperature did peak at over 30C. Data from the Met Office shows that the average UK summer temperature is 18.3C, with temperatures in the south of England nearer 20C. So whilst we may feel constantly bombarded by greyness and drizzle, there is actually a chance that a summer race will be a warm one.

And combining warm conditions with exercise-induced heat present a real risk for heat injury.

So how can you avoid problems with heat? Appropriate gear has an important place, but that’s another story.

A sufficient fluid intake will permit optimal sweating and, therefore, maximise your opportunity for cooling.  

The next – and most important – question, is how much should you drink?

Unfortunately, it’s impossible to provide one-size-fits-all guidelines. The amount of fluid you lose is influenced by several factors, including environmental temperature, humidity, gender, body size and composition, what clothing you wear, how well trained you are, how intense you’re exercising and how acclimatised you are to the heat… You can see why a standard recommendation for everyone isn’t really suitable!

That said, there are some guidelines to assist in working out what you need to be doing. These are based on hydration before, during and after an event.

Before

• Start the race well hydrated. For most people, normal eating and drinking will be sufficient
• To assess your level of hydration, look at your urine (it’s not as weird as it sounds!). Urine should be a pale yellow. The darker the urine, the more dehydrated you are. If your pee is the colour of an Oompa Loompa then get some fluids down you! 
• DO NOT overload on fluids – you’ll probably need to pee mid-race, and excess fluids can be more dangerous than dehydration.
• 5-7ml per kg of body weight, 2-4 hours before the race starts should be sufficient to be adequately hydrated. Unless you assess yourself to be dehydrated, opt for the lower end of the range to avoid the need for unnecessary toilet breaks.

During

• You can work out roughly how much fluid you lose during a run by weighing yourself pre and post training. 1ml of fluid weighs 1g, so a 1kg weight loss equates to 1 litre of fluid. Doing this will let you know roughly how much you’re sweating, so you can tailor your fluid intake to match your losses.
• The general recommendation is to have 400-800ml per hour. Female, slower or lighter runners should aim for the lower end of the range, and heavier/faster runners toward the upper end.
• Sip drinks rather than gulping – small, frequent sips are ideal.
• If in doubt, drink to thirst.

After

• Normal meals and drinks are usually sufficient to rehydrate.
• Eating salty snacks can replenish lost sodium and also promote drinking.
• Check your urine colour again. If it’s dark or you go for a long period of time without needing to pee, keep drinking until you produce pale yellow urine.

What should you drink?

There’s been a bit of debate recently about the benefits, or otherwise, or sports drinks. Whilst there is a lack of evidence to back up some of the claims made by the big brands, for the purposes of hydration, a drink that contains water, electrolytes and carbohydrates does tick all of the boxes.

The consumption of electrolytes (such as sodium) and carbohydrates at the same time as fluid has several benefits.

Firstly, when you sweat, you lose not only fluid but also sodium. Low sodium levels are potentially dangerous and can lead to the development of a condition known as hyponatraemia.

The risk of hyponatraemia is a real one, particularly on a hot day. Drinks can be both refreshing and cooling, and if you keep glugging away then there’s a real chance that some sodium dilution will occur. Drinking an isotonic sports drink is a fairly simple solution (no pun intended!), as is the use of electrolyte products such as those provided by Sis, Nuun or High5 (other brands available J ).

If you do want to combine your hydration strategy with your fuelling strategy, then this can be achieved by using a sports drink. There are lots of brands available – an easy option that ensures you get a decent formulation, convenience and (usually) a palatable drink.

There’s also the option of making your own sports drink. This is usually a much cheaper approach, and can be tailored to your own preferences. Sports drinks are essentially water, salt and sugar, so using those basic ingredients you can make yourself a perfectly serviceable sports drink.

Shop-bought sports drinks typically contain: 6-8% carbohydrates and 200-700mg sodium (0.5 - 1.8g salt) per litre, and this is what you want to replicate in a homemade version.

Being honest, option number one isn’t particularly palatable. The lack of flavour to override the salt can make it difficult to drink, so adding a cordial of your choice is advisable.

An alternative is to use fruit juice.

It really is that simple. You can use whatever juice you like and the benefit here is that there is a blend of different sugars, usually glucose and fructose, which can maximise the uptake of energy into your body.

A word of warning though – anything you plan to do during a race should be tried and tested before race day. The workings of your gut are very much disturbed during prolonged activity, and gastrointestinal discomfort is common amongst endurance athletes. Don’t let months of training be scuppered by experimenting with a new sports drink on race day!

So that’s the basics.

To sum up: hydration is important to sporting performance, which is impaired by both under and over-drinking, both of which have their own risks. A little bit of pre-planning goes a long way in working out what your own needs are, and drinks containing sodium can prevent dehydration and hyponatraemia. And finally, whilst it may seem unlikely, if/when the British summer does delivers on the longed-for warm weather, it’s particularly important to get your hydration strategy right.

Apply the Goldilocks principle: not too little, not too much. You want to get it just right.

Runner's Tum and Toilet Traumas

Runner's Trots

Runner’s trots, runner’s tummy, jogger’s bowels (I may have made that one up…) – whatever you want to call it, the issue of bowel disturbances as a consequence of running (and indeed other forms of exercise) is something that troubles a lot of runners – up to 70% of regular exercises have reported problems with diarrhoea, bloating, cramps, flatulence and nausea.

The extent of the problem can vary dramatically between people, from a touch of nausea after a run in some, to I Must Find a Toilet THIS INSTANT! severe diarrhoea in others. It can ruin training, scupper races and put people off being active.

So what causes it, and what can you do about it?

Identifying the cause of a problem is the first step in finding a solution. And in the case of exercise induced gastrointestinal disturbances, there can be several causes.

Potential cause number 1: The Gut

When you undertake sustained activity - typically 60 minutes plus, several things happen that can affect the way your gut works.

Firstly, when you start exercising, the way the blood flows through your body changes. The oxygen demands of the working muscles increases, and to meet this demand blood flow to the gut is reduced. And the longer you are active for, and the more intense the exercise, the greater the degree of the reduction in blood flow to your gut – some research has indicated that the reduction can be as much as 80% of the normal blood flow.

When blood flow to the gut is reduced, the motility (movement) and rate of absorption from with the intestines is affected. Movement through the gut becomes more sluggish, and ingested foods/drinks are more poorly absorbed than would be normal. This can cause GI symptoms including cramps, nausea, vomiting and diarrhoea – the typical problems we call Runner’s Gut (I may have made that one up too…).  

Secondly, exercise can cause dehydration. Dehydration further reduces the flow of blood to the gut which can further exacerbate GI symptoms.

Thirdly, you get hot (even in British summer conditions!), and this - guess what! further reduces blood flow to the gut .  

So lots of things going on in the way the gut is working.

When you consider putting something in to be digested – a gel, jelly babies, malt loaf, pork pies (or whatever your refuelling snack of choice happens to be) there's obvious scope for exacerbating tummy trouble in a system that’s functioning well below the optimum.

However - and here's a key thing to remember - one of the best ways to increase blood flow to the gut and to reduce some of the problems of dehydration, is to keep stomach volume relatively high. The more there is in the stomach (up to a point - you don't want to be gorging yourself!) the greater the flow of blood. The easiest way to keep stomach volume high and to reduce the effects of heat stress and dehydration is to drink. Water with added electrolytes as a minimum, but adding some carbs in will obviously help to keep energy levels up (either a sports drink or gels/dilute fruit juice/similar along with some water). If you do want to take on carbs - recommended for activity lasting 90 minutes or more - then you need to practise and train the gut to tolerate whatever it is you do to refuel.  

Potential cause number 2: Diet

The foods we eat are an obvious area worthy of investigation when it comes to tummy troubles. There are some usual suspects, but the effect they have on people will vary – so some detective work is needed. The easiest way of doing this is to keep a food and symptom diary. You should soon be able to see a pattern if your symptoms always occur after eating a particular food.

So – the likely culprits:

Fibre

Fibre is good for you. It typically comes in nutrient rich foods – wholegrain cereals, nuts and seeds, fruit and vegetables, it helps you to feel full, can help to lower blood cholesterol, and it’s good for the bowels.

But you can have too much of a good thing.

When you combine a fibrous diet (which gives the bowel a lot of work to do) with activity that reduces the efficiency of the bowel, then you’re almost setting yourself up for a problem. This won't apply to everyone - some people seem to be immune to tummy problems - but others will do well to avoid high fibre foods, particularly if you already have a history of conditions such as irritable bowel syndrome (IBS). Don’t cut fibre out altogether – see above for the health benefits! – but avoid high fibre meals in the 2-3 hours before training, and for a couple of days prior to a race if you are suspicious of fibre and its effects on your bowels. It’s certainly worth experimenting to see if there’s an improvement in symptoms.

Caffeine

Caffeine is well known for its pharmacological stimulant effects, but it’s perhaps not as well known that these effects extend to the stomach and bowels. As well as being a stimulant it is also an irritant, and it is quite common for people with IBS to be advised to reduce caffeine consumption. You don’t have to cut out caffeine altogether, but try avoiding it in the few hours before training and racing.

As an aside, caffeine is often consumed in the form of hot drinks, typically tea and coffee. Hot drinks are known to increase the speed of gastric transit – the speed at which things pass through the gut. Which is to be avoided if you have issues with diarrhoea!

Lactose

Lactose is the sugar found in dairy products: milk, cheese, yoghurt, butter, etc. It is digested by the enzyme lactase, which is produced within the small intestines. Some people are deficient in lactase, and develop symptoms such as abdominal pain, bloating and diarrhoea after eating foods containing lactose. Most people can tolerate small amounts of lactose, even if they are lactose intolerant – it takes a little trial and error to work out your own tolerance level. If you are sensitive to lactose, avoiding it before training and races is recommended.  

FODMAPs

Not a term that most people are familiar with, FODMAPs (Fermentable, Oligo-, Di, Mono-saccharides and PolyolS) are forms of carbohydrates that some people have trouble digesting. They pass through the intestines and are fermented in the large bowel, causing typical symptoms of bloating, cramping, flatulence and diarrhoea.

FODMAPs are found in a wide variety of foods, including apples, pears, stone fruits, honey, wheat, onions, beans, as well as in artificial sweeteners such as sortibol and xylitol, found in chewing gums and mints. It’s not advisable to restrict your intake of all of these without medical supervision – you’re likely to end up missing out on a lot of essential nutrients. Keeping a food and symptom diary can help you to recognise if particular foods are causing your symptoms, and you can use this to carefully amend your diet. It can also help a professional advise you on how to sensibly and safely control your symptoms and maintain a healthy balanced diet.

Drinks sweetened with high fructose corn syrup can be particularly troublesome for some people – check food labels and avoid if you can and if you suspect this may be a source of your symptoms.

Fizzy drinks

Carbonated drinks can promote gas within the stomach and intestines, and this can obviously contribute to bloating, cramping and flatulence – best avoided if you suffer from GI complaints!

Spicy food

Well known for causing tummy troubles regardless of activity, some people are susceptible to the effects of hot and spicy foods. Best avoided, especially in the days preceding race day!

Potential cause number 3: Mechanics

Another thing to consider is the mechanical 'jarring' that comes from running. Some people seem to be more susceptible to this than others, and there's a school of thought that proposes having a strong core can 'buffer' the intestines. So lots of planks and the like may help – it certainly can’t hurt!

Potential cause number 4: Stress

The psychological stress of training and participating in races can have an unexpected effect on the gut: you may not consciously feel stressed, but it can show itself in the bowels. This may be made worse if you’re anxious about previous experiences of Runner’s Gut and are worried about the problem reoccurring.

Resolving this cause of diarrhoea/GI complaints is more complicated than simply avoiding a food – you need to relax! Find a way of avoiding the pre-event jitters that suits your lifestyle, and try not to stress about having to find a toilet or the problem will become self-perpetuating!

General hints and tips

1. Avoid eating in the couple of hours preceding a race. 
2. Try to regulate your bowels – the term ‘bowel habit’ is used for a reason. We can exert some control over where and when we go to the toilet, so having a routine of opening your bowels can prevent unexpected urgency! As peculiar as it may sound, give yourself time to sit on the toilet and relax without fretting! 
3. Have a warm drink and exercise lightly to stimulate the bowels before your training session or race. Once you’ve been to the bathroom, head out and go for gold!
4. Experiment with training at different times of day if you have the flexibility to do so. Training in the evening when you bowels have accumulated the day’s food and drink may make the symptoms of exercise-induced GI problems more likely to occur. Try training in the morning, or timing a training session after you usually empty your bowels.
5. Avoid foods you’ve identified as causing symptoms.
6. Stay hydrated.
7. Stay positive – if you’re new to exercise it may take some time for your body to adjust. If it’s a long-standing problem, try some of the suggestions and try not to fret too much about it, it’ll only make things worse.
8. Locate a toilet! If all else fails, knowing where you can access a toilet can alleviate the worry of having to find one in an emergency.

You may decide to try an over-the-counter anti-diarrhoeal medication, and these may certainly offer some relief from your symptoms. But take caution – regular use of such medications can promote dependence. Not in the sense of addiction, but in that your bowel will start to rely on the presence of the drugs and not function well without them. If you take them pre-emptively they can cause constipation. Medication is an occasional remedy, not a long-term solution!

A Rule To Live By!

If nothing else, please take this on board – do not try something new on race day. No new gels, no new sports drinks, sampling unusual delights from the breakfast buffet, whatever it is: DON’T DO IT!

Putting something unfamiliar into your stomach is a Very Bad Idea. If you want to use gels, sports drinks or the like, find a brand that you like and use it in training. You’ll soon know if it likes you back, or if it has you cramping and running for the toilet. A bit of experimentation is essential if you want to avoid problems on race day. Trying something new for the first time before or during an event is just asking for trouble.

If you know that an event uses a particular brand, test it in your training. If you like it, great. You’ll know that you can grab a bottle/cup from a drink station and not suffer any ill effects. If you don’t get on with it, take your own fluids/gels with you.

Finally – consider getting a check-up with your doctor. If you have a change in your normal bowel habits, or are concerned about any of your symptoms, it’s always best to get yourself checked by a doctor. This topic isn’t something to feel embarrassed about – be sensible and look after yourself!