Questions about isotonic drinks

ISOTONIC drinks are usually associated with sports and events. Can an individual who is not so active drink isotonic drink? 

When isotonic drinks first made their name in the market, their role was for sports performance and endurance.  

Isotonic drinks do play a role in quick rehydration for those engaged in physical activity. Isotonic drinks may be included as a part of your fluid intake along with other beverages within the recommendations. 

 

Are isotonic drinks suitable for people who pursue an active lifestyle? 

It is important for people who pursue an active lifestyle to remain hydrated. Isotonic drinks contain a combination of water, sugar and electrolytes suitable for hydration of the body.  

For people with diabetes who exercise intensively, isotonic drinks may help them to replenish the fluid lost and prevent hypoglycaemia. It is advisable that people with diabetes consult a sports dietitian about their eating and drinking plan prior to their exercise schedule.  

If you are hypertensive, your sodium intake should not exceed 2400mg per day or less 

A cup of isotonic drink (240ml) contains 115mg of sodium chloride.  

So, all foods and drinks that contain sodium should be taken into account if you are hypertensive. It is wise to read the label of a product before you determine the intake of any food or drinks. 

 

What are the ingredients in an isotonic drink? 

The ingredients in isotonic drinks are sodium, potassium, calcium, magnesium, chloride, phosphate and water.  

These are electrolytes, which are basically electrical transmitters, in the body. You can compare them to electrically-charged particles, or ions, in flashlight batteries.  

Sweat that evaporates from the skin contains a variety of electrolytes and fluids. If there is a continual loss of these key electrolytes, this will lead to dehydration and heat stroke.  

The body normally carries out internal regulation of these electrolytes to maintain the balance if the differences are minor.  

It is recommended to replace the loss of these electrolytes by supplying the body with fluid and electrolytes so that rehydration takes place quickly. 

 

How much isotonic drinks can I consume as a part of my fluid plan and once opened, how long can I keep the isotonic drinks? 

The recommended daily fluid intake is two litres. A cup of 250 ml can fit into your fluid plan. However, a variety of fluids such as water, milk, and fruit juices should be in the fluid plan.  

If you consume from the can, it is better to drink as soon as it’s opened, otherwise the carbon dioxide will dissipate from the drink. If you buy bottles, then make sure you screw the cap tightly and finish the drink within two to three days. 

 

Should I drink isotonic drinks cold or at room temperature and what is the shelf life of these drinks? 

Contrary to what you’ve heard, cold drinks aren’t absorbed into the body more quickly than warm ones.  

However, cold drinks are often more palatable than warm ones during exercise or on hot days, so if coldness helps you drink large quantities of fluid while you exert yourself, then keep your drinks cool.  

Most isotonic drinks have a shelf line of nine to 12 months from the date of its production.  

The canned isotonic drinks are impermeable to oxygen and light, and thus have a longer shelf line while the ones in the clear bottles which allow transmission of oxygen and light into the products do have a shorter shelf life. It is recommended that you read the label carefully. 

 

What is the component that quenches the thirst in isotonic drinks? 

Isotonic drinks contain a proper combination of carbohydrates, namely glucose and sucrose, electrolytes such as sodium, potassium and phosphates (minerals lost through sweat) and water. The higher the carbohydrate levels in a drink, the slower the rate of stomach emptying.  

Isotonic drinks with a carbohydrate level of between 6% and 8% are emptied from the stomach at a rate similar to water. Electrolytes in a drink promotes water absorption from the intestine and encourages fluid retention.  

 

Take home message 

Fluid intake is often overlooked in the eating plan. Keep yourself hydrated to optimise your daily work performance. 

 

Note: Mary Easaw- John is a dietitian. The information provided is solely for educating the public and does not constitute an endorsement of any product. Questions regarding its content and use should be directed to a qualified dietitian.