Fitness/Diet and Nutrition
Water, water, everywhere … so make sure that you drink it!
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- For many people, water is often the forgotten nutrient.
- Water keeps your cells hydrated, enabling them to perform their many functions adequately, including energy production.
- You need water to detoxify your body – the liver uses around 1 litre of water per day to perform its detoxification function. If you are not adequately detoxifying, you will not be feeling in peak form and will not be performing optimally.
- It is also an important part of the blood, carrying nutrients around the body; of the synovial fluid which cushions our joints and, through sweat production, helps to cool us down when we get too hot.
- From a sports nutrition perspective, water helps to keep your performance at peak levels.
Performance & Energy
- A lack of hydration will lead to excessive fatigue of muscles.
- When you are dehydrated by only 2% of body mass, performance decreases. With 5% dehydration, performance can decrease by 30%.
- Fluid losses occur in the plasma (the watery constituent of blood), and in and around the cells. Because the volume of plasma will decrease, so the amount of blood flow to muscles (delivering vital nutrients) will also decrease, hence the reduction in performance.
- In addition, lack of blood flow to the skin (an important cooling mechanism), can result in a raised body temperature which can be dangerous. Electrolytes & Carbohydrates
- Sweat contains high levels of the electrolytes sodium and chloride. Potassium, calcium and magnesium are found in lower levels and are equally important. It is vital that these, along with water, are replaced during and after exercise. • Carbohydrate is also an important nutrient to replace to ensure optimal performance, as it increases the uptake of water in the intestine and therefore increases hydration as well as providing a direct energy source.
- For those who find water unpalatable, there are sports drinks, also known as isotonic drinks. The advantage of these drinks is that they contain the electrolytes and carbohydrates that you need to replenish.
Caffeine & Alcohol
- Caffeine and alcohol are both diuretics, so they will increase urine loss and worsen dehydration.
- The inclusion of caffiene (such as is found in many cola drinks) in any post-exercise refuelling can reduce rehydration by nearly 50%.
How much is enough?
- This will vary between people, sports, environments and temperatures.
- A non-active person needs to drink around 1.5-2 litres of water each day to remain adequately hydrated.
- Therefore, any exercise will increase this amount depending on the factors listed above. Rehydration should be incorporated into your training schedule, so that you can learn what the requirement is for you and your sport.
Three key points to remember about hydration:
- Make sure you are optimally hydrated before exercise.
- Provide your body with fluids, electrolytes and carbohydrate during exercise.
- Ensure that you rehydrate and replenish carbohydrates and electrolytes after exercise.
How’s Your Hydration?
For a quick and simple check to see whether you are adequately hydrated, a urine colour chart like this one is very useful!
Collect a sample of urine in a clear jar, discarding the first part of the urine stream, and compare to the chart below. (Caution, if you have printed this chart, you may not have a true representation of the colours you can see on screen.)
Remember that if you are taking vitamin supplements, some vitamins can change the color of your urine for a few hours, making it bright yellow or discoloured, particularly vitamin B2 (Riboflavin). Also, if you have eaten a large quantity of highly-coloured foods (such as beetroot) this will also change the colour of your urine temporarily.
If you are taking a vitamin supplement, you may need to check your hydration status using another method, such as checking the volume of urine (for example, if you rarely urinate, you might be dehydrated).