When my best running buddy, Mark, collapsed at the finish line of the London Marathon a few years ago it struck me more than ever that if we are pushing our boundaries to the limit, we really need to be serious about both our diet and our drinking, not just to enhance performance, but also to prevent injury, exhaustion or worse.
Running makes us sweat; it’s our body’s efficient way of trying to maintain a steady temperature. To find out how to measure how much fluid you lose when you run, click here.
Even mild dehydration can have physiological consequences. As you can see from this graph, a simple loss of just 1% body weight can start to decrease performance (that’s a mere 600ml for a 60kg runner), and a loss of 2% body weight can reduce performance by 10-20% in terms of both mental concentration and focus and physical stamina and co-ordination
If we lose more than this then we can start to suffer from cramps, slower reaction time, reduced judgement and concentration, headaches and so on.
How much should we drink?
There is no ‘one size fits all’ rule to good hydration. Individual factors such as age, size and sex as well as external factors including temperature, humidity, and activity levels dictate how much fluid our bodies need each day. The British Nutrition Foundation recommends that children and adults should drink 6-8 glasses of fluid per day, preferably keeping fluid levels topped up throughout the course of the day, but this doesn’t have to be just water; fruit juice, milk, tea, coffee also count. Many foods have a high water content too. Fruits such as watermelon, blueberries and mango, for instance – click here for some deliciously hydrating recipes.
We should then drink in addition to this during hot weather and before, during and after physical activity.
Hydrate before you run
A good rule of thumb is to hydrate with large glass of water around an hour before you set off for a training run, but you can tell if you are well-hydrated by checking the colour of your urine. A common practice with sports professionals, the pee test is a simple and effective method for runners to monitor their own hydration. A well-hydrated person’s urine is a pale straw-like colour. The darker it becomes, the less hydrated you are.
During a run
During a run, drink when you need to. Don't gulp large volumes if you aren't thirsty – it can result in a condition called hyponatraemia in which your body salts can become diluted, possibily causing confusion and vomiting.
Sports and energy drinks
You can tell just from the taste of your sweat that it’s not made of just water – it’s salty, it makes your eyes sting and, annoyingly, it can stain your clothes. That’s because your sweat is actually made up of water and minerals (electrolytes such as sodium, potassium, chloride and magnesium). These are important for the body to function properly. Sports drinks replace these electrolytes, and, in many cases replenish carbohydrate (energy) levels.
You probably won’t need a sports drink when training for a 10K run, but if in the case of longer runs of over 60 minutes or in hot weather, it is advisable to drink a sports drink containing electrolytes as an alternative to water.
Try this recipe to make your own homemade energy drink:
- Measure out 250ml pure unsweetened fruit juice (I think apple juice works well)
- Add 250ml water
- Add a pinch of salt (about 1/5 teaspoon)
- Mix together, shake well and chill in the fridge.
Rehydrate after your run
Replace lost fluids after your run with water, or if you want to be more adventurous, check out my recovery smoothies and shakes on http://www.gofasterfood.com/hydrate.php. Check the colour of your urine returns to a pale yellow. If you have had a long, hot run, milk makes a highly effective natural sports recovery drink, too, providing:
- fluid and electrolytes for rehydration
- protein to help muscle recovery and growth
- carbohydrate to replenish depleted muscle glycogen stores
If you’d like more information on my Go Faster Food books, check them out on amazon.co.uk or on www.gofasterfood.com.