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Dublin: 5°C Tuesday 2 March 2021

Why staying hydrated is important for your everyday health - particularly in warm weather

Jonny Holland outlines how much water we need to be drinking per day, and the ways we can stay hydrated.

Image: Cathal Noonan/INPHO

HYDRATION IS HUGELY important for your everyday health but also for your exercise and sports performance.

It controls your temperature, especially in warm weather, and gets rid of waste products in the body through perspiration and urination.

Dehydration causes physical fatigue, increases your perceived effort, reduces cognitive function and in more extreme cases, especially during endurance exercise, can cause nausea and gastrointestinal issues.

These are more than enough reasons to focus on getting your fluid intake right. It’s also a big factor in the hangover story but that’s for another day.

People often ask how much water they need to drink per day. You can give rough guidelines such as 2-3 litres for females and 3-4 litres for males but there are a number of variables that influence this number.

Size, genetics, sweat rate, the external environment (heat) and level of activity will all influence how much water you actually need to drink.

With the recent heat wave hitting Ireland, most people should be increasing their intake to avoid dehydration. This is also important when working because of the cognitive and physical levels of fatigue being increased so it has benefits outside of the exercising population.

An easy way to check your hydration status is the urine test. You want your urine to be quite clear to ensure that you’re hydrated.

However, over hydrating to achieve this also isn’t the answer. If you are finding yourself over hydrated and running in and out to the bathroom then it is likely you are in need of some sodium, as this retains water in the body which is where we want it.

Sodium is the fancy name for table salt and is one of the electrolytes that helps to balance the body’s hydration status.

In a sporting context some people may need to increase their sodium intake but for the average exerciser every day foods such as bread, convenience rice and retail soup contain sodium so there is no need to look for more.

Stewards hand out water bottles in The Phoenix Park Source: Oisin Keniry/INPHO

Water isn’t the only way to ensure you get enough fluids. Fruit and vegetables are predominantly made up of water and teas and coffee can also contribute to hydration status.

The duration of exercises can determine what type of drink you use for hydration. During exercises that lasts less than one hour there is no need to consume carbohydrate filled sports drinks.

However, when intensity rises and the exercise bout lasts longer than one hour then sports drinks can be a convenient way to replace lost fluid and consume carbohydrates to keep energy levels up.

To find out more about your own sweat rate you can weigh yourself before an exercise session and weigh yourself straight away afterwards, taking into account any fluids that you consumed along the way.

For every 1kg you lose during exercise you should replace it with 1.5L fluid. This is because some of the fluid being replaced will be lost due to urination.

Some people simply tend to sweat more than others. If you think this is you then you will need to drink more fluids.

Hydration status is very individual so you will need to make your own decisions but start with somewhere around 3L depending on your size and work up or down from there.

If you have any questions relating to these products please leave your comments below or to sign up for a one to one consultation, email

You can follow Jonny’s journey over the next 12 weeks right here:

About the author:

Jonny Holland

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