Powerade Isotonic

In 2006, Powerade launched the Powerade Isotonic formulation of Powerade sports drinks. Powerade Isotonic is designed to be in balance with your body’s fluids to give you fast hydration and energy when you need it most. For those who train hard and push their body to the limits, sports drinks can be a key component to maintaining performance. Water alone isn’t enough when you are playing intensive or endurance sport. Your body needs more. 

What does “isotonic” mean?
The term isotonic means that the fluid has the same concentration of “solutes” (i.e. particles) as that found in your blood and cells. This means that when you ingest it, other fluid does not shift into your gut to dilute it; instead, the fluid in the isotonic drink just readily crosses over into the bloodstream.

What is in a sports drink such as Powerade Isotonic?
Most sports drinks comprise three main ingredients, electrolytes, carbohydrates, and water.

Electrolytes = essential salts

Powerade Isotonic contains two essential electrolytes - Sodium and Potassium. Your body loses these salts in sweat and it is important they are replaced.  The electrolytes in Powerade Isotonic work in two main ways:

• They replace the electrolytes you lose when you sweat.
• They help you to retain fluid so you stay hydrated, as well as maintaining your blood volume, sweat rate and muscle blood flow.  Without electrolytes your urinary output increases (ie. water passes straight through) and you won’t remain hydrated.

There is also evidence that consuming sodium-containing sport drinks, like Powerade Isotonic, stops your thirst mechanism from being switched off prematurely1,2. Although we often look for drinks to “quench our thirst”, you also want to use your thirst to tell you whether you still need to drink more.

Carbohydrates = Energy for Muscles.

Carbohydrate is the main fuel source for muscles when working at a moderate to high intensity (i.e. at jogging pace or faster), and late in prolonged endurance exercise3. It is also the preferred fuel source for the brain4. We have a limited capacity to store carbohydrate (glucose or glycogen) in our body, so those who exercise regularly will require additional supplies from their diet to maintain adequate stores. Studies have shown that providing carbohydrate during exercise results in better exercise performance in sessions of as little as one hour of very high intensity5,6; for sessions of intermittent high intensity exercise, such as football and rugby3,4,7 and for more prolonged (greater than 90 mins) endurance exercise such as long distance running and triathlons3, 4, 7.
 

• Powerade Isotonic provides additional carbohydrates (sucrose & maltodextrin) to provide the energy that muscles need when working out.
• The amount of carbohydrate in Powerade Isotonic is designed to be appropriate for the body to absorb in exercise.
• Adding carbohydrate to a fluid has been shown to assist fluid absorption from the gut and intestine (provided the concentration of carbohydrate is not too high)8.

Why drink a sports drink, as opposed to water?
The two main perspectives which differentiate a sports drink from water alone are the additional supply of fuel (carbohydrates) and electrolytes with the hydration. Also several studies have provided evidence that people will drink more of a flavoured drink than an unflavoured one1,6. Hence, a refreshing, palatable drink such as Powerade Isotonic will generally be consumed more readily, thereby further enhancing total fluid intake and reducing the risk of dehydration. Powerade Isotonic comes in a great range of flavours, all of which make it easier for you to keep drinking the amount you need to stay hydrated.

REFERENCES:

1.  Wilk B., Bar-Or O. 1996. Effect of drink flavour and NaCl on voluntary drinking and hydration in boys exercising in heat. J. Appl. Physiol. 80: 1112-1117.

2. Wemple R., Morocco T., Mack G. 1997. Influence of sodium replacement on fluid ingestion following exercise-induced dehydration. Int. J. Sport Nutr. 7: 104-116.

3. Coyle E.F. 2004. Fluid and fuel intake during exercise. J. Sports Sci. 22: 39-55.

4. Maughan R. 2006. Fluid and CHO intake during exercise. In: Burke LM and Deakin V. (Eds). Clinical Sports Nutrition, 3rd Edition. McGraw-Hill: Sydney. pp 385-415.

5.  Jeukendrup A., Brouns F., Wagenmakers A.J., Saris W.H. 1997. Carbohydrate-electrolyte feedings improve 1 h time trial cycling performance. Int. J. Sports Med. 18: 125-129.

6. Below P., Mora-Rodriguez R., Gonzalez-Alonso J., Coyle E. 1995. Fluid and carbohydrate ingestion indpendently improve performance during 1 h of intense exercise. Med. Sci. Sports Exerc., 27: 200-210.

7. Sawka M.N., Burke L.M., Eichner E.R., Maughan R.J., Montain S.J., Stachenfeld N.S. 2007. ACSM Position Stand - Exercise and Fluid Replacement. Med. Sci. Sports Exerc. 39: 377-390.

8. Maughan R. 2006. Fluid and CHO intake during exercise. In: Burke LM and Deakin V. (Eds). Clinical Sports Nutrition, 3rd Edition. McGraw-Hill: Sydney. pp 385-415.

Using Powerade for training and competition

To avoid dehydration and get the most out of yourself and out of your sports drink, you should drink before, during, and after sport.  Powerade Isotonic is perfect for each of these times.

How can Powerade help me before sport?

Drinking sports drinks, such as Powerade Isotonic, before intense exercise helps to ensure that you begin in a well hydrated and well fuelled state. This can be particularly useful if you find it difficult to eat, or find you need many bathroom stops prior to exercising.  Starting exercise well hydrated is vital; leaving it until you are on the field or track may be too late.  This is particularly crucial for longer duration exercise, or activity undertaken in hot, humid conditions, and even for people whose primary exercise is actually manual labour.  Sports drinks like Powerade Isotonic can also help you start with plenty of energy.

How do I make sure that I start my exercise optimally hydrated?
Unfortunately drinking one litre of fluid half an hour before starting your session isn’t going to rehydrate you effectively. Instead, this should be undertaken over a period of at least several hours, with around 400-600ml in the 2hr before exercise1. A good hint is to set up a hydration strategy that suits your lifestyle. Athletes need to ensure they continue their fluid intake consistently in between training sessions. If you are working, ensure that you have access to fluids at hand.

Some suggestions include:

1. Set a timer on your computer / watch to remind you to drink something every hour.
2. Take a drink  bottle to work / uni / school and keep it in sight all the time. If you work outdoors, keep it in an esky to keep the fluid cool.
3. Set up a dispenser in your workplace so you always have chilled drinks on hand.
4. Always have something to drink when you have a meal, as many nutrients in meals can help promote adequate hydration2.
5. Keep an eye on your urine output throughout the day. Aim to keep it reasonably clear in colour most of the day (although this doesn’t count if you’ve just recently consumed a large volume of fluid in one hit).
6. Fluids can include water, milk, juice, sports drinks, cordial, soft drinks, tea and coffee and can all be “counted” towards total fluid intakes over the day, although you need to consider the impact of their energy content as well.

If you know you’ve left yourself a little short in terms of fluids and food just prior to exercise, try drinking a sports drink, such as Powerade Isotonic before you exercise to top you up.  The electrolytes will help your body hold onto the fluid effectively.

How can Powerade help me during sport?

Regular replacement of fluid is the main consideration during any sports event.  During exercise, Powerade Isotonic is designed for optimal provision of fluid and fuel.  These benefits aren’t just for your muscles.  . By helping to maintain hydration and providing fuel to combat fatigue, Powerade Isotonic can also help your reactions times, concentration and coordination.   Powerade Isotonic can help you perform at your peak for longer.

It is recommended to use Powerade Isotonic during training sessions before using it in competition, in order to determine your own individual stomach (gastrointestinal) comfort. You may be able to train your gut to tolerate more fluid if you build your fluid intake gradually11.  This can be in the form of plain water for shorter bouts of exercise, but for longer events the fluid should also include small amounts of carbohydrate, like that found in Powerade Isotonic.

In the early 1900’s, it was believed that people shouldn’t drink during exercise as it was bad for you. Not drinking was meant to “toughen you up”. However, research has shown that drinking during many forms of exercise is actually good for you.  Obviously, in many sports and forms of exercise, it’s not practical to drink – such as a 100m sprint, a judo bout, or during an Olympic rowing or kayaking race! If you’re only exercising at a low to moderate intensity for a relatively short time (less than 20-30 minutes), especially in cool weather, then there is no need to take on fluid during the session as you should be sufficiently hydrated before hand.

Why should I drink during exercise?
There are various effects that dehydration has on both performance and on the body during exercise.  

What should I drink?
The choice of what you drink partly depends on the duration of exercise, the environmental conditions, and personal preference. In exercise of 60 minutes or longer, especially in the heat, there is good evidence supporting the use of a sports drink (such as Powerade Isotonic) over water due to both the electrolytes and the carbohydrate in the drink. If you’re not a good drinker, then having fluid with some flavour in it will help you drink more4, 5. However, if you’re exercising for less than an hour and in cool conditions, then water may be adequate.

How can Powerade help me after sport?

Powerade Isotonic is ideal for fast replenishment of fluid and fuel to muscles to get you ready for the next training session. This is particularly important for those doing more than one training session per day.  It is well recognised that even though sweat rates vary considerably between individuals, voluntary fluid intakes during exercise generally only meet around 50% of fluid needs. Hence, most people finish exercise dehydrated.

Why is rehydrating important?
Rehydrating is important for many reasons, but basically it’s to get the body’s system back into shape as quickly as possible after exercise. If you don’t rehydrate effectively, you can suffer the ongoing effects of dehydration for many hours after exercise – including tiredness, the inability to concentrate, and dull headaches. For those who exercise at least once a day, the failure to rehydrate generally means they may start the next exercise session in a dehydrated state.

When should I rehydrate?
Rehydration should start as soon as practical after exercise, with the overall goal to consume 150 % of the fluid you lost during the session in the next few hours6. For example, if you lost 1 kg (1000g) mass during the exercise session, you need to drink 1.5L (1500ml) in the next one to two hours.

The reason you drink more than what you sweated is to account for the fact that you continue sweating even when you stop exercising (at least until the body’s core temperature returns to normal), and because inevitably some of this volume will end up as urine. It is better to drink to a plan over a period of time, rather than in a haphazard way or all in one go! Planning is especially important in older adults whom, it is now known, have a reduced thirst sensitivity when dehydrated7. As most of us already know the ‘one hit’ drinking plan will generally only result in more of the fluid going into the toilet, not to mention making you feel extremely bloated and uncomfortable! BUT, it doesn’t stop there – continue to drink regularly throughout the day, rather than just at meals, in order to maintain hydration levels. If you drank well during the exercise session and didn’t lose any weight, don’t forget that you still need to drink afterwards as well, as you’ll continue sweating for a while.

What should I drink?
Sports drinks can help you rehydrate because they contain water, electrolytes and carbohydrates.  Other fluids may be also used to rehydrate, however, they may not be as efficient.  For example, water on its own has not been shown to be effective in rehydrating over a four hour period where individuals had dehydrated nearly 2 % during exercise in the heat8. Similarly, most soft drinks don’t contain enough sodium, which is the key electrolyte influencing rehydration, so would be as ineffective as water in rehydrating you. Despite the commonly held belief that caffeine-containing fluids further dehydrate you, research now shows that caffeine at moderate doses does not promote dehydration at rest or during exercise. 

However, such beverages also do not provide improved rehydration compared to water or a non-caffeinated drink9.  If you’re going to eat a meal soon after exercise, then water should be a sufficient rehydration fluid10 since the meal generally contributes electrolytes and nutrients which help promote uptake of the fluid you consume (Note: some foods contribute fluid themself – such as fruit, vegetables and dairy products)7.

 If you don’t plan on eating, then a sports drink such as Powerade Isotonic has the advantage of sodium (salt) which helps your body retain and use the fluid more effectively, as well as carbohydrate to help recover muscle fuel stores. The other advantage of a sports drink is that it doesn’t switch your thirst receptors off prematurely – in other words, it keeps you sensing “thirst” until such time that you are adequately rehydrated.

References:

1. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. 2007. Exercise and fluid replacement. Med. Sci. Sports Exerc., : 377-390.

2. Institute of Medicine. 2005. Water. In: Dietary reference intakes for water, sodium,, chloride, potassium and sulfate. Washington DC: National Academy Press. pp 73-185.

3.  relates to 80% rule
4. Minehan MR, Riley MD, Burke LM. 2002. Effect of flavour and awareness of kilojoule content of drinks on preference and fluid balance in team sports. Int. J. Sport Nutr. Exerc. Metab. 12: 81-92.

5. Wilk B., Bar-Or O. 1996. Effect of drink flavour and NaCl onvoluntary drinking and hydration in boys exercising in the heat. J. Appl. Physiol. 80:1112-1117.

6.  Shirreffs SM, Armstrong LE, Cheuvront SN. 2004  Fluid and electrolyte needs for preparation and recovery from training and competition. J Sports Sci. Jan;22(1):57-63.

7. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. 2007. Exercise and fluid replacement. Med. Sci. Sports Exerc.: 377-390.

8. Shirreffs SM, Argon-Vargas LF, Keil M, Love TD, Phillips S. 2007. Rehydration after exercise in the heat: a comparison of 4 commonly used drinks. Int. J. Sport Nutr. Exerc. Metab. 17: 244-258.

9. Fiala KA, Casa DJ, Roti MW. 2004. Rehydration with a caffeinated beverage during the non-exercise periods of 3 consecutive days of 2-a-day practices. Int. J. Sport Nutr. Exerc. Metab. 14:419-429.

10. Maughan RJ, Leiper JB, Shirreffs SM. 1997. Factors influencing the restoration of fluid and electrolyte balance after exercise in the heat. Br. J. Sports Med. 31: 175-182.

11.  Rehrer NJ. 2001. Fluid and electrolyte balance in ultra-endurance sport. Sports Med. 31: 701-715.