Training & Nutrition

6 Signs to Indicate Dehydration is Setting in

The subtle, and not so subtle signals that your body is suffering from dehydration, and needs that water bottle

One of the most important pieces of kit to take with you on any ride is a full water bottle, with enough fluids to see you through your adventure. If you’re ill-equipped, you may suffer from serious dehydration.

Dehydration is a serious problem amongst athletes and those putting their bodies through regular or intense exercise. The recommended daily intake of water for an adult is approximately 2 litres, but this should be increased during periods of training, and even over your monthly visit when your core temperature rises.

How to manage your hydration levels on the bike

It may not be as sunny recently, but it’s certainly still humid – and it’s important to remember that you sweat as you ride even when the weather is cool.

So what happens when you’re not replenishing the water tanks properly?

What is Dehydration?

The human body is approximately 2/3 water, and that liquid plays a vital role in how our body functions. It aids the lubrication of the eyes and joints while contributing to a healthy digestive system. When water is lost, it affects the salt balance in the body which will hinder your performance.

When the your body’s water content drops by 1-2 per cent, you’ll begin to feel thirsty because your body needs you to replenish lost fluid. Losing more than this can result in a number of symptoms which, if left untreated, can lead to severe health issues which require medical assistance.

Being thirsty is one of the more obvious signs of being dehydrated, but there are other subtle alarm bells you should get familiar with before your body and workout begin to suffer.

Elevated Heart Rate

Of course your heart rate will be elevated during a work out, but if you notice an unusual increase of roughly 20-30bpm, then it could be a sign of dehydration setting in.

Your heart will try to compensate for the reduced blood volume in the body by beating faster to get the oxygen and blood flowing.

Light Headedness and Dizzy Spells

The light headed feeling you get from standing up too quickly is called postural hypotension – it occurs when there’s not enough blood getting to your brain. This is owing to low blood volume.

So if you’re in the gym, on the bike and changing positions when this happens, it may be time to take a few minutes rest and quench your thirst.

Gravity Skin

Ever looked in the mirror, or pinched your skin for it to feel a little “bleugh”? Decreased skin turgor is when the skin on the back of your hand doesn’t spring back after being pinched. This is a key indicator of dehydration.

When hydrated, pinch the back of your hand for a couple seconds to gain a baseline for future testing.

Concentrated Pee

The stronger the colour and smell of your urine, the more fluids you need to take.

Ensure you drink and go to the toilet regularly, as soon as severe dehydration sets in, urine production decreases dramatically and this can have serious health consequences.

Bad Breath

Illustration: Britt Appleton

Saliva is packed full of useful enzymes to help with the process of chewing food and breaking down the components ready for digestion. Saliva also contains many anti-bacterial properties, but when you’re dehydrated, it’s difficult to produce as much saliva.

The reduced level of saliva allows bacteria to build up on on the teeth and around the mouth. This can hugely contribute to bad breath – no kisses for you.


You’re brain is encased within a fluid sack, a little like an internal helmet to protect it from bumping into the skull. If this watery helmet is depleted, you’re brain can push up against the skull and cause some painful pressure.

Drinking fluids is essential to maintain and regulate your body’s health so it can function at its best. If left for prolonged periods of time, crystals can form in the kidneys and eventually turn into painful and uncomfortable stones which will need medical treatment.

A general rule of thumb is to try and consume roughly 2 litres of water per day, and increase this when training. If you notice any of the warning signs that you’re dehydrated, take a break and drink some water to fill up the tanks.

High salt content diets and alcohol can dehydrate the body quicker, too – sorry!

You may also enjoy:

10 Foods that can help keep you hydrated

6 of the best MTB hydration packs

The benefits of drinking lemon water

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