It is important to stay on top of our hydration. Increases in temperature often means we lose more fluid, as our body sweats to cool us down – especially if working or exercising outdoors in the sunlight. But how exactly do we make sure that our bodies are well hydrated?
Ideally, fluid should be replaced in accordance with sweating rates. It is important to note that there are large differences between individuals when it comes to fluid lost through sweat, even when completing the same activities under the same conditions. This is especially important for athletes to monitor, as recovery after a training session or competition can be vital for performance at the next session. Some athletes may see fluid losses that equate up to 2% of their body weight, which can begin to impact performance, especially in hot temperatures (>30ºC). Exceeding this amount could result in heat stress and delay recovery times, impacting performance during the next exercise session.
Fluid losses can result in decreased blood flow around the body and as a result, increases in core body temperature. High intensity exercise is the biggest risk factor for heat stress as a result of dehydration. It is best to avoid dehydration by replacing lost fluids when exercising for 60 minutes or longer, especially in bouts of high intensity exercise.
There are many products marketed toward athletes, such as sports drinks. Some commonly found within Australia include Gatorade, Powderade and Staminade. These sports drinks can be useful for effective recovery of athletes, when used appropriately. They are typically made up of fluid, electrolytes, and carbohydrate, which are specifically balanced and designed for rehydration and refuelling, during or after exercise.
*Carbohydrate: is our bodies first choice of fuel for the brain and muscles. Carbohydrate can be found in the form of various sugars such as glucose, sucrose, fructose or maltodextrin, with most drinks containing somewhere between 4-8g of carbohydrate per 100ml.
*Electrolytes: including as sodium and potassium. Sodium is the main electrolyte lose through sweat, and the sodium added to sports drinks increases fluid absorption and retention. Potassium is another electrolyte which aids muscular contractions.
Additional added ingredients include flavours, vitamins, minerals and proteins. These most likely offer very little or no added benefits, and are rather added for palatability. Some drinks may also contain caffeine, which can improve performance.
For athletes, sports drinks may be useful during exercise when the activity lasts for a duration of 60-90 minutes or longer. They may also be useful for recovery after a prolonged exercise session, to replace carbohydrate (glycogen) stores and electrolytes lost through sweat. For short bouts of exercise, or low intensity sessions with little loss of fluid, sports drink may not be necessary.
But what about those of us who aren’t elite athletes, but want to stay on top of our hydration? While sports drinks can be useful for athletes, they are not necessary on an everyday basis for those simply looking to quench their thirst. They tend to be quite high in energy as well as sugar. Many range from 600-1200kJ of energy and 10-14 teaspoons of sugar in 1 standard drink. On an everyday basis, water is more than likely sufficient to prevent dehydration.
It is important to consume sufficient water following an exercise session, with individual requirements that will vary, however drinking to thirst should be sufficient. Take note of the temperature, as you will most likely need to drink more fluid on a hot day. The need for sports drinks is dependent upon the duration, intensity and environment of the exercise you are undertaking. For individual nutrition advice regarding hydration and recovery, see one of our Accredited Practising Dietitians.
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Volume 34, Issue 4
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