What exactly are these "isotonic sports drinks"?

31 October 2018

There is a growing number of isotonic sports drinks on the market, mainly intended for physically active people. What makes companies attribute so many great properties to them? How are they better than ordinary mineral water and when is it best to drink them?

Sports drinks should provide the body with the necessary mineral components, rebuild carbohydrate reserves and prevent water loss during exercise. This is possible thanks to the particular composition of the drink and the appropriate osmolarity.


Osmolarity refers to the number of molecules contained in a fluid. It is osmolarity that impacts the speed of gastric emptying and the absorption of liquids. And that is where the most famous isotonic sports drinks play the key role - because their osmolarity is similar to the osmolarity of body fluids. How does it benefit us? First of all - faster absorption compared to other beverages, and on top of that, not only hydration, but also maintaining the level of water and minerals at the appropriate level!!

  • WATER - the main component of isotonic drinks; largely affects our fitness, but does not provide energy;
  • CARBOHYDRATES - easily digestible (such as glucose, fructose and sucrose), a good source of energy, delays the onset of fatigue;
  • ELECTROLYTES - sodium above all, which has the most scientifically documented physiological benefits. Thanks to its ability to bind water, it maintains the appropriate blood volume, prevents dehydration and increases the speed of restoring fluid balance during the post-workout period. The other electrolytes are magnesium, calcium and potassium, which care for the muscular and nervous systems.

Many people choose to take ordinary mineral water with them for training. Is that the right thing to do? Can drinking water alone protect us from the unwanted effects of dehydration? Of course! In case of a training session that lasts up to one hour, mineral water is the most optimal drink. Having drinks enriched with carbohydrates and electrolytes is more befitting when we exercise intensively - usually longer than an hour - as they refill fluids and add energy.


Unfortunately, ready-made isotonic drinks available in stores are mostly a chemical mixture, often containing large amounts of dyes, preservatives, aromas and often, artificial sweeteners! Therefore the best healthy isotonic sports drinks are the ones you can prepare yourself, at home.

In addition to what we drink, it is also worth paying attention to how we drink. During exercise drink slowly, taking small sips.

shutterstock_6467236002.jpg [852.73 KB]RECIPE FOR A SIMPLE DOMESTIC "ISOTONIC DRINK"


  • 500 ml of mineral water
  • Juice from a half of a lemon
  • 2 tablespoons of honey
  • A pinch of salt


Mix all ingredients thoroughly until obtaining a consistent liquid, and drink during training or immediately after finishing a physical activity.


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  • Demirhan B., et al.: The Effect of Drinking Water and Isotonic Sports Drinks in Elite Wrestlers. Anthropologist 2015, 21: 213-218.
  • Moreno I.L., et al.: Effects of an isotonic bevereages on autonomic regulation during and after excercise. Journal of the International Society of Sports Nutrition 2013, 10: 1-10.
  • Ostrowska L., Orywal K., Stefańska E.: Zaburzenia gospodarki wodno-elektrolitowej. W: Diagnostyka laboratoryjna w dietetyce. PZWL Wydawnictwo Lekarskie, Warszawa 2018.