By Kate Morland – Registered Nutritionist
'Don't get into the habit of eating or drinking in a marathon race: some prominent runners do, but it is not beneficial'. J.E. Sullivan 1909.
Thankfully, we’ve come a long way since then. Carbohydrate replacement and hydration are two crucial nutrition priorities for any sport lasting 90 minutes or longer; particularly when you factor in things like heat, high intensity, multi-discipline events and the desire to perform at your best.
Carbohydrates, Fluid & Electrolytes – To replace or not to replace?
Carbohydrates are our working muscles’ primary fuel. Without replenishing your carbohydrate stores, you are likely to conk out, forcing your body to work extra hard to break down alternative stores to provide fuel.
Likewise, sodium is the major electrolyte depleted during exercise through sweat. Without adequate replacement, it can lead to detrimental fluid shifts that result in hypo-hydration; impairing heat regulation, increasing heart rate and fatigue, and reducing mental function.
A 2% loss in body fluids can reduce performance by 20%. For example, an 85kg male cycling at an average of 35km/hr may lose 1.7kg over 90minutes of cycling, dropping his average speed to 28km/hr.
Current recommendations for exercise that lasts longer than 90 minutes suggest you need 30-60g of carbohydrates per hour during exercise to offset depletion and fatigue. It is best to take this at regular intervals throughout the hour. As a benchmark, you should aim for ~1L/hr of sodium containing fluids.
However, one size does not fit all. The optimal quantity of carbohydrate, fluid and electrolytes per hour is highly individual depending on gastrointestinal tolerance, sweat rates, exercise duration, intensity and climate.
It is really important to practise and practise again with timing, quantities and types of fuel during training to fine-tune what works best for you before competition day.
Sports Drinks - what to look out for
Sports drinks are a convenient and economical way to tick all the boxes; keep your blood glucose levels elevated, replace fluid & electrolyte losses, and provide fuel to working muscles.
A sports drink should ideally contain a concentration of 4-8% of either glucose or glucose-containing carbohydrates e.g. maltodextrin, and also contain 0.5-0.7 g/L (20-30mmol/L) of sodium. Balance Restore Energy Powder
is an isotonic electrolyte formula that’s perfect for consuming before, during and after training or racing to ensure optimal hydration and carbohydrate fuelling. Based on drinking 700ml per hour, you’ll get 50g carbohydrates (a combination of maltodextrin, fructose and glucose). You can opt for a caffeine or caffeine-free formula in lemon, orange or berry flavours. Caffeine aids focus and concentration during times of fatigue.
Balance Energy Squeezegels are another convenient way to replace carbohydrates during exercise. Each gel provides 25g of carbohydrate in the form of maltodextrin, which will be absorbed rapidly. Plus they also come in a caffeine and caffeine-free formula.