When my best running buddy, Mark, collapsed at the finish line of the London Marathon a few years ago, dehydrated and in a bad way, it struck home to me that I needed to understand more about hydration. What does it mean to be well-hydrated? How does good hydration affect athletes, especially endurance athletes such as runners, triathletes, cyclists and swimmers? How much should we drink? Can you drink too much? Is water the best drink? Should I be drinking sports drinks? What is a sports drink? What are electrolytes? 

Whatever your sport or activity, dehydration can creep up on you and before you know it, your performance starts to dip and your concentration wavers, you lose focus and in bad cases, risk exhaustion, disorientation and injury.

We can all tell we are dehydrated if our mouth is parched but how much fluid we actually need varies a lot from individual to individual. 

How can I tell if I am well-hydrated?

It's all about the colour of your urine! The best way to tell whether you are drinking enough is to do the pee test...

The Pee Test

The pee test is a great way to find out if you are hydrated or not.

If your pee is dark yellow, this is an indicator that you need to drink more.

The paler yellow your pee is, the more hydrated you are. Aim for a pale, almost clear colour. 

Try these top hydration tips

1. Drink water or fluids regularly throughout the day, whether you are training or not...

My hack is to kick the day off to a good start by keeping a pint of water by your bed and drinking it as soon as you wake up. Continue to drink regularly throughout the day. If you're prone to forget, set an alarm for mid-morning and mid-afternoon! Water is the best bet, but other fluids are fine too, such as tea, juice, even soup!

Just avoid sugary drinks, and, in my opinion, also artificial sweeteners.

2. Replace lost fluids with a sports drink if training for over an hour - your sweat contains more than water!

You can try to sip as you go - easier if you're on the bike than if you're running - and drink to thirst. Drinking whilst running needs practice; after many years of running I still find this virtually impossible. One solution is to invest in a hydration vest. I've just bought one for my son which he loves from Decathlon.

You only really need to take on a sports drink if you're running or cycling for over about an hour. This is because your sweat contains more than just water. Just taste your skin after a long sweaty run - it is incredibly salty. Your sweat is made up of electrolytes which are vital for your body to function properly, such as sodium, potassium, chloride and magnesium.

When you sweat, you lose approximately 2.g to 3.4g of sodium per litre of sweat and you can actually lose up to 1 litre of sweat per hour during a race. For this reason, it is recommended that you drink a sports drink with sodium and electrolytes in it, rather than simple water, when running for more than an hour.

 Try your own homemade electrolyte sports drink! 

Try making your own sports drink - much cheaper and just as effective. Mix 500ml apple juice, 500ml water and a pinch salt.

Fresh juice, a fruit salad or a piece of fruit straight after a run, bike ride, football training or any sporting activity will rehydrate you too and provide carbohydrate to replenish your glycogen stores. It should also boost your sodium and potassium levels, along with other essential minerals such as iron, copper, iodine and magnesium and anti-oxidants such as vitamin C, A and E.

3. Be wary of hyponatremia (water intoxication)

Water intoxication (hyponatremia) is occurring more frequently as greater numbers of recreational sports enthusiasts take part in long-distance events. When the 22-year-old fitness trainer tragically died after completing the London Marathon in April 2007, the condition became more widely known.

Hyponatremia is caused by drinking so much water that the sodium concentration in the blood becomes diluted to the extent that vital body functions are jeopardised. This is why a sports drink with sodium and electrolytes is so important for longer rides and runs.

Unfortunately the symptoms of dehydration and hyponatremia are very similar. The tell-tale sign of dehydration is dark urine but other indications are very similar - muscle cramps, disorientation, dizziness, nausea, weakness and extreme fatigue. Stick to a basic rule of drinking before or when you are thirsty and keeping up your salt intake and you should be able to avoid any serious consequences.

4. Don’t just stick to water, snack on hydrating foods.

Juicy fruits such as oranges and watermelon (97% water) provide great hydration. Try this delicious watermelon and feta salad – it’s hydrating and packed with electrolytes.

"Water is boring and sports drinks are expensive and sickly!" This is a comment I hear all-too-frequently from my sporty friends. The fact is, however, that you can get your water from many sources other than the tap - on a hot sultry sunny day when your body is crying out for liquid, what could be more refreshing than a sweet, succulent slice of watermelon made up of 97% water?

Fruit juices too, are a great alternative for athletes, because they contain extra calories and vital minerals and vitamins. Raw fruit and vegetables all have a high water content - melon, strawberries, apples, citrus fruits, red fruits, pineapple, kiwis, tomatoes, broccoli, carrots, peppers, spinach, cabbage, radishes...take your pick! Even some relatively 'dry' foods contain a high percentage of water, such as beans, grains like couscous and rice and pasta (foods which expand with water). In hot weather you can very easily base your everyday diet on foods that include higher levels of water, while still providing your body with the correct level of carbohydrate, protein, vitamins and minerals.

5. Salty foods, too, will replace electrolytes lost through sweat

A marmite sandwich as a post workout snack works a treat! When it is really hot or you are training or competing in the desert (marathon des sables for instance) make sure that you keep up your salt intake with salty foods or salt tablets to minimize the risk of diluting your blood too much with pure water.

 6. In hot weather, choose a shady route to run in. 

Choose your route carefully. Head for the woods rather than sticking to the tarmac which soaks up the heat! Take enough fluid with you.

 7. Time your rides and runs carefully

Try not to run in the heat of the day. Set off early before the day heats up the ground, or late in the evening when the days cools off.  If you’re not accustomed to running in the heat, you need to get your body acclimatized before you attempt anything too adventurous. Start your runs slowly and don't run too far until your body get used to the heat. If you are planning to race in a hot country get in some training in similar conditions.

 8. Pour water over your head to cool down...

You can lose 70% of your body heat through the top of your head, so when it is really hot, and in races, don’t just drink water, pour water over yourself when you run to cool you down.

9. Wear appropriate clothing and sweat proof sunscreen

Wear light, loose-fitting clothes made with high tech material rather than cotton, which can cling to your skin. Head to Boots for a good selection that's not too pricey...

10. Recognise the warning signals. Don’t run through heat cramps.

Stop if you feel faint, weak, dizzy or confused. Rest, get into the shade and drink a sports drink.

I hope you'll like these hydrating recipes - packed with the Kate Percy #Enerjoy!

Italian-style Roasted Peppers – Kate Percy's (katepercys.com)

Tropical Power Punch with Ginger and Turmeric – Kate Percy's (katepercys.com)

Thai Pineapple and Cucumber Salad – Kate Percy's (katepercys.com)

Andalucian Gazpacho Soup – Kate Percy's (katepercys.com)