HYDRATION IN SPORT PERFORMANCE
In this article we shall cover the following points so you can keep on top of hydrating yourself to maximise performance and health.
The body consists mainly of water, with fluid accounting for around 60% of your total body weight according to figures detailed in the Parkland Trauma Handbook (Third Edition). [1]
Therefore, your body needs water to grow and to maintain health.
In this article we shall cover the following points so you can keep on top of hydrating yourself to maximise performance and health.
- The importance of water
- Fluid intake for athletes
- Working out your ‘sweat rate’
- Round up
Importance
The Association of UK Dietitians report that “…good hydration is one of the most important aspects of the diet…” [2]
This is because many of the processes that are happening in your body, right now as you read this, are only possible because of water.
It ranges from the blood being able to carry oxygen to your muscles and organs to helping lubricate your joints, your eyes and mouth.
Furthermore, without water (or dehydration) your digestive system would also fail to operate., you can become more susceptible to infection
Even a 2% rate of dehydration which is considered mild can have a negative impact on brain function according to the American College of Sports Medicine. [3]
However, without really reading into this, you are not aware of these actions. However, one you would be more accustomed to is temperature regulation when you are hot.
This could because it is a hot day in the summer, or you’ve been running around a rugby pitch all afternoon.
When you are hot (eg. due to climate changes, exercise, or clothing) your body’s mechanism to cool you is through sweating. When you sweat the evaporation of the moisture from your skin cools the body helping you maintain an ideal temperature. [4]
Clearly, when you sweat, you are losing liquid, so for this cooling function to work properly you need fluid in your body.
Studies published by the University of Connecticut have shown that even a modest increase of dehydration can raise core body temperature and have a negative impact on performance. [5]
The NHS recommends that an average person in the UK should consume about 1.2 litres of water every day based on the climate and fluids obtained from foods. [6]
However, your own requirements can vary based on levels of exercise and exposure to different temperatures.
Fluid intake for athletes
Being hydrated ensures that your body is operating effectively.
A athletes’ needs are different to the average person, due to additional stresses and demands placed on the body.
Specifically, for a rugby player, being well hydrated helps maintain the lubrication of joints and can help reduce inflammation as well as preventing gout as per the information outlined by the Arthritis Foundation. [7]
Water also helps protect your organs, tissues, and spinal cord by acting like a cushion which is particularly useful in high contact sports. [8]
Furthermore, even losing 2% of total body weight through dehydration can have a negative impact, yet athletes can lose from 6-10% when performing. [9]
This level of dehydration can result in the following negative effects:
- Increased tiredness
- Less endurance capacity
- Effort feels more difficult
- Reduced body temperature control
- Lower levels of motivation
A loss of body fluid that is not replaced has a greater effect on high intensity and endurance-based activity than other exercises such as weightlifting. [10]
To prevent this impact on physical performance, or to reverse the effects simply restore lost fluids or drink enough before exercise. [11]
How much fluid should I drink?
Your thirst mechanism is your way of knowing that you need a drink. However, if you are feeling thirsty you are most likely already dehydrated.
We’ve already mentioned that in the UK a person needs about 1.2 litres of fluid per day. It is difficult to know how much each person loses fluid as everyone is different.
However, for someone participating in sports or exercise the British Nutrition Foundation suggests that it’s a good idea is to drink approximately 750ml of fluid 2 hours up to a game or training and your urine should have a pale-yellow colour. [12]
During exercise, you need to be aware that you will lose water through sweat and even from breathing, to rehydrate aim for regular fluid replacement every 10-20 minutes of 125-250ml to prevent a reduction in performance.
After exercise or competition, monitor your urine colour and aim to maintain that pale-yellow colour similar to champagne. Ideally you need to replace 150% of what you lost.
This is a merely a rough guide, but to know in more detail what your fluid requirements are there’s a simple way to find out.
Calculating your sweat rate
It’s good practice to know what your sweat rate is whilst exercising, knowing this means that you can hydrate effectively to minimise loss of performance. Additionally, whilst the rough guidelines regarding hydration for sport are a good rule of thumb, it won’t be optimal as everyone sweats at different rates.
To find out how much you sweat (and how much fluid you need to replace) follow these simple steps:
- Ensure you are hydrated. Check your urine colour and make sure it is pale yellow.
- Weigh yourself naked in kilograms and note the weight.
- Exercise for 1 hour to the same intensity as your normal training or playing routine.
- After 1 hour, weigh yourself naked again and log your weight.
- Subtract the second figure from the first weight.
Grams and kilograms equal millilitre’s and litres.
Therefore, 100g equals 100ml. 1kg (1000g) equals 1 litre.
If your first weight was 70kg and the second weight after the exercise was 69kg your ‘sweat rate’ was 1 litre per hour.
Therefore, when you are next training or playing you need to drink 1 litre throughout that period.
Likewise, if the first weight was 50kg but the second weight was 49.5kg you have lost 500ml of fluid. Therefore, during that 1 hour of activity you need to drink 500ml of fluid.
Please note that is just fluid to drink throughout the activity period per hour.
You should always start activity fully hydrated, replace the amount of fluid you have calculated to lose during activity and maintain hydration after activity.
Further consideration
If you are going to establish your sweat rate consider your climate, and when you train or compete.
There’s no point knowing how much you sweat per hour when it is very cold during the winter and carrying that over into summer because your sweat rate will change and so ill the demands placed on your body.
If you are playing through different seasons, do a sweat rate calculation for each season or typical weather pattern, then you can adapt accordingly.
The round up
Being hydrated is key to many bodily functions such as brain health, blood pressure, digestion, muscle performance, sleep and even helping fight infection.
Even a mere 2% loss of fluid can reduce performance and feeling thirsty can mean you’re already dehydrated.
During activity, your fluid requirements will increase as demands on your body increase.
A general rule of thumb is to drink 1.2 litres per day in the UK, but as your activity levels rise, drink more to maintain a pale-yellow urine colour.
If in doubt of your fluid requirements, simply calculate your sweat rate by using following the steps above.
These are the personal views of Ben Bunting, a former player at Chesterfield Panthers and currently studying a Postgraduate in Sports Exercise and Nutrition at Leeds Beckett Carnegie School of Sport (Leeds Beckett Carnegie School of Sport).
References:
[1] https://www.sciencedirect.com/science/article/pii/B9780323052269500608
[2] https://www.bda.uk.com/resource/the-importance-of-hydration.html
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4207053
[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6773238/
[5] https://ksi.uconn.edu/wp-content/uploads/sites/1222/2015/04/Influence-of-Hydration-on-Core-Temperature.pdf
[6] https://www.nhs.uk/live-well/eat-well/water-drinks-nutrition/
[7] https://www.arthritis.org/health-wellness/healthy-living/nutrition/healthy-eating/best-drinks-for-arthritis
[8] https://www.cdc.gov/healthyweight/healthy_eating/water-and-healthier-drinks.html
[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908954/
[10] https://pubmed.ncbi.nlm.nih.gov/19223668/
[11] https://pubmed.ncbi.nlm.nih.gov/19344695/
[12] https://www.nutrition.org.uk/press-office/pressreleases/hydration-for-optimum-athletic-performance.html