ENERGY BARS These are solid, so take longer to be absorbed into the bloodstream. This may be a disadvantage in shorter races, but can work in your favour over longer distances. They’re also good before a long race. Some people find bars more palatable than gels.
SWEETS Anything with a high sugar content will help restock your body’s glycogen stores quickly, although you won’t get extra ingredients like electrolytes. Sports nutrition sweets are also available.
MALTODEXTRIN This is often the primary carbohydrate source in gels and energy drinks. It’s derived from cornstarch, easy to digest and delivers energy quickly.
GLUCOSE The most common carb in nature, also often known as dextrose.
FRUCTOSE Derived from fruit sugar, and absorbed via a different pathway to glucose, so when taken in combination it can increase your body’s maximum carbohydrateabsorption rate.
SUCROSE Glucose and fructose combined. Otherwise known as table sugar. SODIUM A key electrolyte. ELECTROLYTES Important body salts and minerals, which are lost via sweat. For more information, see the hydration section, p26.
CAFFEINE A stimulant that has been proven to boost performance and lower perceived exertion. Research shows you need 3mg per kg of body weight, but consider the timing of your caffeine hit, as it only reaches peak effect an hour after consumption. Try it in training so you know how it affects you.
● SIS GO Energy + Double Caffeine gel (150mg per gel), £11 for 6, scienceinsport.com
● Myprotein Energy Elite + Caffeine gel (75mg per gel), £17.99 for 20, myprotein.com
● Maxinutrition Fuelmax Plus gel (100mg per gel), £40.99 for 24, shop. maxinutrition.com
NITRATES Naturally occurring in some vegetables, (beetroot is a particularly rich source), nitrate is converted into nitric oxide in the body, which increases blood flow and oxygen delivery. Exeter University research found that drinking 500ml of beetroot juice a day for six days increased time to exhaustion by 15 per cent. Also, ‘acute doses’ taken just before exercise have been shown to boost performance. In one study, 6.6mmol (the amount of nitrate in a Beet It Sport Shot, see below) taken between two and two and a half hours before exercise improved performance by 2.8 per cent.
WHAT KEY INGREDIENTS SHOULD I LOOK FOR WHEN I’M CHOOSING CARBOHYDRATE PRODUCTS?
HOW MUCH WATER DO I NEED TO DRINK WHEN I’M RUNNING?
The best advice is to drink according to your thirst – it’s a strong predictor of your hydration needs. ‘Our thirst mechanism is pretty accurate,’ says Susan Yeargin, assistant professor of physical education at the University of South Carolina, US. In fact, drinking too much water can lead to a condition called hyponatraemia, in which salt levels in the blood become dangerously low, with symptoms that range from headaches and nausea to seizures, coma and, in extreme cases, death. A simple way to find out your hydration status is to check the colour of your urine. If it’s clear or pale yellow, you’re well hydrated. But if it’s the colour of apple juice or darker, you need to drink up. For runs shorter than an hour you can go without water, provided you’re well hydrated at the start. During longer runs the options are to wear a hydration pack (a backpack containing a water bladder and mouthpiece), or plot a route that passes your home or other point where you have stashed water. You could also try long runs with isotonic energy gels (which provide a little hydration, as they contain water) but without water itself – if trying this, build distance/duration gradually to allow your body to get used to them. During half- marathon races and longer, drinking little and often (a few mouthfuls at each aid station), rather than gulping down lots in one go, will be easier on your stomach.
SHOULD I AIM TO REPLACE THE AMOUNT OF FLUIDS I’VE LOST AFTER A RUN?
If you sweated a great deal, replenishment of fluids is important, but, again, you can judge how much you should drink simply by thirst. If you want to be more precise, there’s a fairly easy way to work out your needs, says Dr Chris Easton, lecturer in exercise physiology at the University of the West of Scotland. ‘ Weigh yourself before going on a 60-minute run. Don’t drink anything while you’re out and towel off any excess sweat when you get back; then weigh yourself again. Each gram in weight you’ve lost equates to 1ml of fluid, so that figure is how much fluid you need to replace for every hour of training.’ So, if you lost 1kg of weight, your sweat rate is one litre per hour and you could aim to replace at least this amount over the course of the rest of the day.
WHAT ARE ELECTROLYTES, AND HOW IMPORTANT ARE THEY TO A RUNNER?
Electrolytes are salts and minerals that control the fluid balance of the body, and they play a key role in muscle contraction and energy generation. Sodium, potassium, magnesium and calcium are among the major electrolytes. They’re lost through sweat, so it’s good idea to replace them after a hard workout, especially if you’re a salty sweater (look for white marks on your kit or even your skin after a run). Some sports drinks contain electrolytes, and you can also buy tablets that add flavour and electrolytes to water with virtually no calories or carbs.
WILL DRINKING TEA AND COFFEE DEHYDRATE ME?
While caffeine provides a proven performance- boosting edge, it also acts as a diuretic, right? Well, not exactly. ‘Recent research shows that caffeine doses between 250 and 300 milligrams – the equivalent of about two cups of coffee – will minimally increase urine output for about three hours after consuming it,’ says Yeargin. ‘However, the research also shows that exercise seems to negate those effects.’ So, ultimately, you can consider tea and coffee (and other liquids such as fruit juice) as contributing to your daily fluid intake. Just be sure you get your caffeine hit at the right time
When it comes to hydration, listen to your body: it knows what it needs.