Keeping hydrated whilst driving

Today, we’ll be discussing something few of us ever stop to think about… staying hydrated whilst driving. We’ve previously given much thought to why you should stay hydrated in the gym, but why should you stay hydrated whilst driving? Bear with us, and we’ll tell you why and how you should keep your hydration levels up whilst driving.

Why do I need to hydrate whilst driving?

Most of us are reluctant to drink much water during car journeys, as we try to limit our toilet break numbers, but this choice could be ill advised, even fatal. Scientists at Loughborough University (Watson, Whale, Mears, Reyner, Maughan, 2015), recently undertook a study on young male drivers between the ages of 22 and 26. They asked participants to undergo a two hour driving simulator, in which they drove a virtual car on a motorway on separate days, one where they were fully hydrated, and one where they were not provided with adequate hydration. The number of driver errors were recorded during these driver simulations.

The results of this study were very clear, drivers who were dehydrated made more than double the number of mistakes on the road than those who were hydrated. Drivers who were hydrated made, on average, around 47 mistakes during the driver simulation, drivers who were dehydrated made, on average, around 101 errors. This is around the same amount as those with a blood alcohol level of 0.08%, otherwise known as ‘drunk drivers’.

How do I stay hydrated whilst driving?


Prior to any journey, ensure you are adequately hydrated and rested. Food with water content, can contribute to your hydration level, indeed certain fruits can provide a great deal of hydration, such as watermelons, which are 92% water. Ensure you hydrate at least 45 minutes prior to setting off on your journey, and you’ll find your alertness and energy levels will noticeably increase. To reach adequate hydration, take your weight in pounds, and divide it by two. This will provide you with the number of water ounces you should be drinking in a day. Divide this out by your waking hours to ascertain how much fluid you should be drinking in the time before your car drive.

You should also check that the temperature within your car is ambient, as heavy use of air conditioning whilst driving can cause profuse sweating, leading your hydration levels to dip even more rapidly.

If you find you are thirsty whilst driving, if possible, pull over to hydrate, drinking fluid whilst driving is not illegal, but does make you 18% more likely to show erratic lane control. If this is not possible, make use of a straw cup, which will allow you to hydrate quickly, and does not require two hands. It’s worth bearing in mind that it takes 45 minutes to become fully hydrated if you are mildly dehydrated, so taking time to pull over, and perhaps stretch your legs, is probably the wisest choice.

What next?

Equip yourself with the tools to remain hydrated whilst driving, monitor your driving environment, and increase your fluid intakes on warm and sunny days, and your driving mistakes will reduce, and your alertness levels will increase. It’s a no brainer! To read more about hydration and driving, read these NHS tips, here.