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The Basics |
The loss of fluid and a reduction in the body’s carbohydrate stores are the two major causes of fatigue in prolonged exercise. Therefore it is essential that you define your optimal nutrition and hydration strategies to ultimately help you to achieve your running goals. |
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Fuel |
When you run your body needs energy. This energy comes from what you eat and what you drink. The body’s preferred source of energy is carbohydrates that are stored in your muscles and liver as a ‘fuel’ called glycogen.
The body’s glycogen stores are limited and fatigue occurs when glycogen stores are depleted resulting in significant reduction in running speed. Crossing the start line with already low glycogen stores is like taking a car out with a half empty fuel tank – you will run out of fuel more quickly and may suffer premature fatigue. |
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Carbohydrate
Carbohydrate feeding before and during prolonged performance has been shown to reduce the negative impact of glycogen depletion in performance*. So, as a runner you need to ensure you eat plenty of carbohydrates to keep these stores topped up. When you are training, at least 60% of your daily calorie intake should come from carbohydrates (e.g. pasta, rice, bread, cereals and potatoes).
However, you should not base your carbohydrate intake on percentage alone, this is a good indicator, but it is best to also follow the below** suggested guidelines, which are based on grams per kilogram of body weight.
Moderate duration/ low intensity training: 5-7g per kg per day
Moderate to heavy endurance training: 7-12g per kg per day
Extreme exercise performance: 10-12g per kg per day
In the same way that varying your training and racing helps to promote fitness and prevent boredom, varying your diet will also mean that the essential energy, nutrients and fluid that support your running are easier to obtain. While you can never prevent coughs and colds occurring, certain nutrients can help to maintain a healthy immune system.
Eat a balanced diet including plenty of carbohydrate from a range of carbohydrate sources, including starchy foods such as bread, pasta, rice and potatoes, as well as simple carbs such as honey, jelly and marmalade. |
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Fat
Although not the preferred source of fuel for exercise, fat is a very concentrated source of fuel for the exercising muscle, principally at low intensities. Fat is also essential in the diet for providing soluble vitamins. As an overall proportion, the percentage of fat in the diet should comprise no more than 25-30% of total energy intake, with less than 10% coming from saturated fat.
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Protein
Protein is also important, since it contains the essential amino acids that are the building blocks for muscle growth and repair. While meat and dairy products are good examples of protein-rich foods, it should be remembered that high doses of protein won’t develop strength any more than a sensible intake of around 1.5 grammes per kilo of body weight per day. |
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Vitamins and Minerals
A diet with plenty of fresh fruit and vegetables should provide the vitamins and minerals that are needed to keep the body healthy and sustain the immune system. While there is no evidence that supplementing the diet with extra vitamins will improve running performance, anyone who thinks their diet might be deficient in certain nutrients may benefit from taking a daily multivitamin supplement or a boost of vitamin C or zinc, which can help to sustain the immune system. |
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Hydration
In many cases, athletes begin training without being hydrated, which not only affects the quality of training in the short term but makes it even harder to hydrate in time for their next training session.
In an ideal world drinking strategies are individually tailored, as some people are naturally heavy sweaters compared to others. However, given that not everyone has access to the help that they need; the following tips are widely recognised as guidelines for fluid intake before, during and after exercise:
250ml in the half hour before training before training
125-150ml every 15-20 mins during training but no more than 500ml per hour
500ml (approx) after exercise depending on your sweat loss during exercise (note the advice on weight loss below)
You can be much more accurate about how much to drink after training by weighing yourself before and after. For every kilogram lost this should be replaced with 1.5L of fluid. Weigh yourself wearing the least amount of clothes possible to improve the accuracy of the results.
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Hyponatraemia - Are you drinking too much?
Although very rare, runners involved in longer distance events do have to be aware of over-drinking; a condition known as hyponatraemia. Hyponatraemia is defined as ‘low concentration of sodium (or salt) in the blood’ and may occur as a result of three combining factors:
- Prolonged exercise (>4hrs) that results in large amounts of sweat and total sodium loss
- Drinking too much, i.e. excessive volumes of fluid intake greater than individual sweat rate
- Drinking a fluid that does not contain sodium (predominantly water) [1]
- The risk of hyponatraemia is further increased if you exercise in the heat, as the greater sweat
rate will lead to a greater total sodium loss compared to normal climates.
If hyponatraemia occurs, then the resulting decrease in sodium concentration in the blood has serious implications for both normal and exercising bodily functions, where in the first instance performance is reduced, but perhaps more importantly can pose a serious health risk.
What are the signs and symptoms of hyponatraemia?
Those suffering from hyponatraemia may demonstrate any of the following symptoms: fatigue, bloating, upset stomach, nausea, headaches, cramps, disorientation, slurred speech and confusion. If hyponatraemia remains untreated, hyponatraemia can be very serious leading to collapse, convulsions and sometimes even death (although this is very rare in UK climates). Whilst anyone maybe susceptible to hyponatraemia in certain situations, it does appear that women are at a much greater risk than men, because they are smaller and more likely to develop a fluid overload simply because it takes less fluid for small people to become overloaded [2].
Prevent weight gain from excessive drinking
In a study of the 2002 Boston marathon [2], 13% of finishers were treated for hyponatraemia. After statistical analysis it was revealed that weight gain, i.e. a greater amount of fluid was consumed than lost through sweat, was the greatest predictor of hyponatraemia. Therefore, hydration advice remains unchanged; drink at a rate that matches sweat loss, or at the very least drink to prevent a decrease in body weight of 2% or more [3]. This can be easily measured by weighing yourself before and after exercise to ensure a stable body weight. Furthermore, once corrected for fluid intake, body weight change will give a measure of sweat rate which can be used to base drinking strategies on in future training sessions. For example, if your weight before a training session was 70kg, and 69kg after, and you drank 500ml of fluid throughout, your total fluid loss through sweat was 1.5 litres (1litre = 1kg). Therefore, ideally you would try to consume 1.5 litres during a similar training session in order to optimise your hydration status.
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Drink fluids that contain sodium
To maintain healthy levels of sodium in the blood, it is advisable to consume fluids during training that contain sodium (i.e. fitness drinks or sports drinks). Drinks containing sodium also have the added benefit in that they are designed to rehydrate you quicker and more effectively than plain water. |
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Hydration in the winter months
The same ‘golden rule’ of maintaining hydration applies during the colder months of the year. Even when the conditions are cold and wet you can still lose significant amounts of fluid through sweat, so making sure you start a run properly hydrated is essential.
Although sweat rates may be lower in cold conditions, fluid is still lost in vapour clouds that are created every time you breathe out. Check the colour of your urine to ensure it is light or straw coloured, as this is a basic guideline to ensure that you are hydrated. Drinking isotonic drinks like Lucozade Sport or hypotonic drinks such as Hydro Active remains an important way of maintaining hydration while also aiding your recovery. |
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Focus
How many times have you stood at the start of a race, wishing there was something you could take to make you run faster? Well, there is – and it’s completely legal.
Caffeine is currently only one of a handful of supplements that have sports science research behind them to demonstrate that they can improve performance. Caffeine is a naturally occurring compound which, although classified as a drug, is currently legal in sport and remains off the list of WADA (World Anti-Doping Agency) prohibited substances. Its most common consumption is in various forms of coffee, tea and soft drinks, providing approximately 30-100 mg of caffeine per serving.
Caffeine consumption can affect the body in a number of ways, although the main mechanism is the inhibition of adenosine receptors. As adenosine receptors are found all over the body, it is virtually impossible to understand the underlying mechanisms behind the performance effect of caffeine. However, it would seem that caffeine predominantly improves performance through the central nervous system by reducing the perception of effort.
There’s no doubt that caffeine will improve your performance – the only question is by how much. In a nutshell, caffeine helps to reduce the perception of effort for a given running speed. As a result, runners start to run faster and cross the finish line quicker. Caffeine is also known to help improve focus, alertness, concentration, memory and reaction time, which although less important than feeling better and running quicker, may at some stage during a training session or race help optimise performance.
As with trying anything for the first time, do not try anything new on race day. Also, remember that Lucozade Sport with Caffeine Boost will not be available at the start of the Flora London Marathon. So if you’re planning to use caffeine as part of your race strategy, make sure you include it in your race bag.
What benefits can I get from using caffeine when training and racing?
There is no substitute for a good quality training program, well-balanced diet, and a sports nutrition strategy that gets the basics such as carbohydrate intake and hydration right. However, if you are happy with your overall physical, mental and nutritional preparation then caffeine may help provide you with that extra edge in performance that could enable you to achieve that new personal best time.
When should I take caffeine?
You should start consuming caffeine one hour before the start of your race as this is the approximate time that its takes for caffeine to work its way through the body to peak in the blood stream. Higher intakes of caffeine will not always result in an increased performance benefit and it is currently suggested that an intake of 1-3 mg/kg body weight improves performance. The key to understanding whether caffeine is something for you is to trial it in training and races and see how you feel and perform. This will also help you to decide how much caffeine you need to consume, within the recommended levels.
Will caffeine give me the same benefit when running different distances?
Caffeine appears to exert a positive benefit across the energy spectrum (from events ranging from seven minutes through to full-on endurance events). Therefore, whether you’re competing in a 3K race, half marathon or marathon, caffeine has the potential to help improve your performance.
I’ve heard caffeine is a diuretic – is this true?
One of the most commonly held assumptions about caffeine is that it is a diuretic. Whilst caffeine is a diuretic under resting conditions studies suggest that under exercising conditions caffeine does not adversely affect hydration status. As long as you stay well hydrated as usual, there is no reason why athletes should avoid using it in training and races.
Are there any side effects when using caffeine in running?
Caution should be taken when ingesting high doses of caffeine (greater than 500mg per day) as it can have side effects. However, side effects are individual in nature and therefore caffeine ingestion should be trialled in training prior to use in competition. If side effects occur an athlete should consult their physician. |
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