Strategies for staying hydrated in the heat this Summer

Choose the right sports drink to keep your body in tip-top shape when it's scorching hot

Canadian Cycling Magazine July 24, 2019

Staying hydrated is vital for strong performance on the bike. There are many sports drinks on the market to choose from, but how do you decide which one is right for you?

Sports drinks contain sugars, artificial sweeteners, flavours or colouring, and different amounts of carbohydrates, calories and electrolytes. But the best drinks are made from natural ingredients and supply enough sodium chloride without excess calories.

The body gets rid of heat during exercise by increasing blood flow near the skin and sweating. Sweat has fluid and electrolytes such as sodium, magnesium, potassium and chloride. Sodium is the most important electrolyte because it’s crucial to maintaining the body’s water balance. There are serious consequences if the body’s sodium levels drop too low.

Athletes lose between 500 mL to 2,000 mL (17 to 67 fl oz) of sweat per hour. Your body becomes dehydrated if you don’t replace fluids and electrolytes lost through sweat. When you’re dehydrated your body can’t cool down as well because you sweat less and have less blood volume. This will impair your endurance and increase your perceived effort and fatigue.

Dehydration also causes your heart rate to increase and generates more body heat. Central fatigue happens when the body temperature rises towards 39.5 C (103 F). This can lead to heat exhaustion and become life-threatening. Drinking cool beverages help lower core body temperatures.

Sweat loss can be measured by weighing yourself naked before and after exercise. Calculate what you drank during your ride and add this to the difference in weight before and after your ride. This total is close to what you’re losing in sweat for that period of time. A professional sweat test can determine how much sodium you’re losing in your sweat.

You shouldn’t lose more than one or two per cent of your body weight because of fluid loss during your ride or your performance will be affected. Dehydration not only impairs power and performance but can also impair your ability to focus.

It’s important to practice good hydration while riding. Drink fluids that replenish sweat loss and don’t cause stomach aches. Practice drinking more during training to get accustomed to riding with a full stomach. Starting a long ride with a stomach full of fluid can keep you hydrated longer.

Add sodium (500–700 mg/L) to your drink if you’re riding for longer than one hour. Not only will it replace lost sodium, but it will stimulate thirst, which will make you want to keep drinking.

As long as you’re drinking optimal amounts of electrolyte-rich fluids, the remainder of your calories can come from solid food. Too many carbs in a drink can impair the rate of absorption and hydration.

The best sports drinks have electrolytes and are made with natural ingredients. They also have more than 600 mg of sodium per litre, they’re not too sweet, have no fructose (which can cause stomach aches) and include natural products.