Fact1: “Isotonic drink is better in promoting hydration when is compared to other types of beverages.”
Sweating is the way in which the body maintains its core temperature at 37 degrees centigrade. This results in the loss of body fluid and electrolytes (minerals such as chloride, calcium, magnesium, sodium and potassium) and if unchecked will lead to dehydration and eventually circulatory collapse and heat stroke. There are two main factors in fluid absorption that affect the speed at which fluid from a drink gets into the body:

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, especially sodium and potassium, in a drink will reduce urine output, enable the fluid to empty quickly from the stomach, promote absorption from the intestine and encourage fluid retention.
The osmolarity of a fluid is a measure of the number of particles in a solution. In a drink these particles will comprise of carbohydrate and electrolytes. In blood plasma, the particles will comprise of sodium, proteins and glucose. Drinks with an osmolality of 270 to 330mOsm/kg (which is similar to that of blood) which is in balance with the body's fluid are called Isotonic. Isotonic drinks quickly replace fluids lost by sweating and supply a boost of carbohydrate. Glucose is the body's preferred source of energy therefore it may be appropriate to consume isotonic drinks where the carbohydrate source is glucose in a concentration of 6% to 8%.
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Fact 2: "Tea or coffee cannot help in hydration.”
Tea and coffee contain caffeine; dehydration is one of the results related to caffeine over consumption. Caffeine affects the kidneys by acting as a diuretic, which increases urine production and therefore increases loss of water from the body. Tea and coffee can be source of fluid; however, it does not contain electrolytes that are lost in sweat and required to enhance rehydration. It is best to consume these beverages when hydration status is back to normal within the recommended amounts.
Adequate hydration is important for all individuals, and isotonic drinks serves as a choice of rehydration fluid for consumers who enjoy its refreshing taste, or wish to avoid or moderate calories, caffeine, sugar or the various ingredients found in other beverages within the recommended amounts.

Fact 3: -“If your urine is dark it means you're dehydrated.”
According to research, the colour of your urine could reveal a lot about a person's health, a diagnostic technique which is being overlooked. In a healthy person, urine ranges in colour from almost clear to bright yellow because of a pigment known as urochrome. But once the urochrome becomes concentrated, urine can go dark yellow or brownish, which suggests it's time for a drink.
It's a marker of hydration (which can) be used as a marker of whether you're drinking enough fluid, particularly in hot humid days. If sweat is more, then urine will be concentrated more due to less availability of water to carry solutes. If water intake is increased, the concentration automatically gets diluted and the colour will resume to normal. But if you find yellowish urine even after plenty of water intake, it is better to rule out jaundice.
Usually, morning urine is more concentrated than at other times since we do not drink water at night. So, to maintain the water balance of our body, less water is excreted and thus the urine becomes more concentrated. Isotonic drinks do play a key role in keeping the body hydrated and if your variety of fluids intake is increased, the urine concentration gets diluted and the color of the urine will remain light colored. To achieve your fluid intake, drink a variety of fluids such as water, juices, isotonic drinks, soy milk and milk within the recommended allowances of fluid.

Fact 4: Energy drink cannot also be used for hydration.
The goal of rehydration is to replace fluids and lost electrolytes in your body in the right balance. Isotonic drinks are specifically formulated to enhance hydration and optimize physical performance. Studies support the performance enhancing benefit of isotonic drinks for exercise lasting anywhere from 30 minutes in duration. Consumption of isotonic drinks post exercise also promotes rehydration and glycogen replenishment
The amount of carbohydrate present in energy drinks (e.g. 10-12%) is similar to soft drinks and is much higher than isotonic drinks (usually 6-8% as recommended by International Guidelines.).
Energy drinks have either too little sodium or too much. Sodium is an important electrolyte in isotonic drinks as it helps to optimize hydration and maintain thirst drive. Isotonic drinks are formulated with the right mix of carbohydrates and sodium for optimal hydration and taste. Energy drinks unlike isotonic drinks may contain caffeine or guarana which is diuretic which increases urine production and elevates the risk of dehydration. Some energy drinks may contain ginseng, gingko Biloba, taurine an amino acid and inositol a sugar alcohol which have not proven the role in maintaining hydration.

Fact 5 – Isotonic drinks are suitable for people who pursue an active lifestyle
It is important for people who lead an active lifestyle to remain hydrated. Isotonic drinks contain a combination of water, sugar and electrolytes is suitable for hydration of the body. For people with diabetes who exercise intensively, isotonic drink may help them to replenish the fluid lost and prevent of hypoglycaemia. It is advisable that people with diabetes consult the sports dietitian about their eating and drinking plan prior to their exercise schedule. However, for people with diabetes who do not exercise or maintain active life, this may increase the chance of causing the blood sugar to run too high. A serving of 240 ml (approx 1 cup) of isotonic drinks may contain 16 g of total sugar which contributes to 3 teaspoons of sugar.
If you are hypertensive your sodium intake should not exceed 2400 mg per day or even lesser than this amount. A cup of isotonic drink of 240 ml 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 product before you determine the intake of any food or drinks.

By Mary Easaw – John, Consultant Dietitian. The writer has 23 years of experience in the field of nutrition and dietetics. The information is solely for educating the public and does not constitute an endorsement of any products. Questions regarding its content and use should be directed to a qualified dietitian.