• Wendy Ballard

Hydration: How to be cool with your fuel

When we think about how much our bodies are actually made up of water it is no surprise how essential water/fluid is for us to maintain a healthy lifestyle. But what is ok and not ok to hydrate with. There are lots of conflicting advise out there that says you cannot count tea or coffee into this equation because the caffeine makes you go to the toilet more! I hope that this blog helps you to decide what is ok to drink and how much you should drink but first of all we are going to talk about dehydration.

Photo by MRJN Photography

Dehydration occurs when you do not drink enough fluid. Studies have shown that just 1% dehydration (equivalent to 1% of body weight water loss) can cause negative effects on mental and physical function. These symptoms come more severe as the dehydration becomes worse. Most of you will recognise the symptoms of mild dehydration, dry mouth, headaches, poor concentration and generally feeling sluggish, these are all ques for you to drink more. So, what happens in our bodies when we become dehydrated? Our kidneys filter our blood which contains water and when our bodies detect that more water is needed the first thing that happens is that the kidneys reduce the amount of water lost in our urine. This means that the colour of our urine becomes darker as there is less water in it. See the chart to see what healthy urine looks like. You should be aiming to have your urine a pale straw like colour. Measuring your dehydration by your urine colour is more accurate than waiting to become thirsty. Your thirst mechanism is very sensitive and it is easy for you to override this or just not recognise it especially when we all lead such busy lifestyles. Sometimes your body will make you feel hungry as an attempt to gain fluid from food. Often if this occurs having a drink will make the hunger disappear. Another thing to remember here is that thirst kicks in when you are already dehydrated so the best way to keep hydrated is to keep toping yourself up with fluid even when you are not thirsty.

How much fluid do you need to drink?

To be precise this will depend on your body weight, your activity level and the environment that you are in. However, as rule of thumb 6 – 8 glasses per day should be sufficient to keep most people hydrated. If the weather is hot or you are doing exercise or you are unwell and have a temperature you may have to drink more.

Be cool with your fuel

Essentially, all non alcoholic drinks are suitable plus you can get quite a lot of fluid from food. You do need to be careful about sugar content for example fruit juices, fizzy and non fizzy soft drinks, are high in sugar and therefore contain calories so not a great choice if you are trying to lose weight. Milk and water are great hydrating drinks for children. Milk does contain more calories but it also contains essential minerals and vitamins that support growth. A huge market is developing for the use of sports drinks and the big here is, should you use them? One thing you need to consider is how much exercise are you doing and for what purpose are you exercising. If you are exercising to lose weight it is unlikely that you will be training at athlete level and if you are exercising to lose weight you really do not want to be having extra calories from a sports drink. You will require extra fluid to make up for that loss as sweat and it will also depend on the temperature and humidity of the surrounding environment that you are exercising in. It is a good idea to start exercising already hydrated so if your urine is a 5 or 6 (see the accompanying chart) your performance will be much better if you hydrate first and then top yourself up during exercising.

Water is absolutely fine for rehydrating following/during moderate exercise that most active people choose, and the majority of active people at this level do not need a special sports drink to rehydrate. High intensity exercise that last’s for longer than 1 hour or more a sports drink containing some sugars and sodium (salt) may be of benefit to replacing lost fluid and salts from sweat. See the drinks below to decide what is best for you to hydrate.

Drinking water/tap water

The body does not have to break this down before absorption so it gets into your system quickly. Contains no calories so it is by no surprise the best choice.


Milk contains lots of essential vitamins and minerals as well as protein and calories. It is a great choice for children but do go for a semi skimmed if your child is over 5 or is younger but are over weight. 1% or skimmed milks are not suitable for children until they are 5 years as they contain less vitamin A.

Fruit juices and smoothies

These will provide you with vitamins and minerals plus water. BUT, they also contain lots of calories due to the sugar in fruit. If you do enjoy a juice or smoothie try to only have 150mls maximum per day. This will also contribute to 1 of your 5 a day fruit and vegetables.

Tea and coffee

There are lots of do they or don’t they count towards your hydration status. The answer is yes, they do even though they do contain caffeine. Caffeine can make your body produce more urine so consuming moderate amounts is best. Pregnant women should only consume no more than 200mg of caffeine per day. This is equivalent to 2 mugs of instant coffee or 2 ½ mugs of tea.

Drinks such as hot chocolate/Horlicks etc can be quite calorific so if you are trying to gain weight, great, but if you are trying to lose weight go for a lower calorie one that is made up with water.

Herbal and fruit teas, usually these do not contain caffeine or sugar, however, green tea contains caffeine so it needs to be consumed in moderation.

Sugary drinks

Fizzy drinks, squashes, juice drinks, flavoured waters these drinks can contain a lot of calories. There is equivalent to 8 teaspoons of sugar in one can of fizzy drink. That is not just a load of calories but also a significant amount of sugar to be swishing around your teeth! If you do like to go for a soft drink aim for ‘no added sugar’ or ‘diet’ drinks or ‘sugar free’ versions.

Sports drinks

These usually contain some carbohydrate and electrolytes. Adding electrolytes into the drink help’s the fluid from the drink to be absorbed quicker. It also helps to replace lost salts from sweat. These drinks do not need to be consumed if you are doing moderate exercise you can get your hydration from water and the loss of salts from the food in your next meal. If you are doing high intensity exercise such as an endurance event that lasts more than 1 hour then you would benefit from a sports drink to preplace salts from lost sweat and they will also provide a carbohydrate boost during exercise.

Energy drinks

These can be high in sugars and very high in caffeine and other stimulants. These drinks are not suitable for children and teenagers.

Alcoholic drinks

These will make you pass more urine and for this reason alone will not provide you with much hydration. In addition, they also contain calories for example a (175ml) glass of 12% wine contains around 125 calories and a 5% pint of lager contains about 215 calories. It is advised that you keep within your recommendations per week of alcohol which is 14 units for both men and women.


It does not contribute quite the same amount as fluid but it does contribute. You can get up to 20% of total water intake from food. Fruits and vegetables have a highwater content. Other foods such as soups, stews, yoghurts, custards and jellies will also contribute to your daily total fluid consumption.

I hope that you have found this blog interesting and it has helped you to become more cool with your fuel and keep yourself hydrated.

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