Isotonic drinks are characterised by a concentration (osmolarity) that is similar to that of body fluids. That is why their beverage hydration index (BHI) is higher than that of water. BIH allows us to estimate how much fluid that we drink can be retained in the cells of our body. However, you don’t have to buy expensive sports drinks to stay well-hydrated. You can prepare your own isotonic drink at home and adjust it to your own needs.
How to choose the components for a homemade isotonic drink?
A homemade isotonic drink can have as many advantages as a specialist drink found in sports shops. There are several important aspects of these drinks. Let’s look at the method of composing them step by step.
Electrolytes in a homemade isotonic drink
The most important element of a homemade isotonic drink is a well-hydrating base. You can use:
- water (ideally highly mineralised)
- coconut water
- skimmed milk
- plant-based drink (preferably protein-rich soya milk)
This hydrating base delivers mainly fluids, but it additionally contains electrolytes. Their presence is the main characteristic of isotonic drinks. Electrolytes are cations and anions dissolved in water. Thanks to these particles, the fluid is isotonic relative to cells and can be retained better in the body. High electrolyte content distinguishes isotonic drinks from ordinary water. These include: sodium, potassium, calcium, magnesium, and others.
The simplest home method to increase the electrolyte content of a drink is to add some kitchen salt (sea salt or Himalayan salt), i.e. sodium cations and chloride anions. Sodium is the main mineral that is lost with sweat. Isotonic drinks usually contain 40 to 80 mg of sodium in 100 mL. However, adding salt to drinks isn’t the healthiest option for most people: a typical Pole consumes too much salt and dietary sodium anyway. Add salt to a hydrating drink only when you are expecting a long, intensive effort with a significant loss of sweat.
Alternatively, other additives that supplement drinks with electrolytes are:
- fruit juices (e.g. orange juice, pomegranate juice, lemon juice)
- full fruit
- vegetable juices (e.g. celery juice, tomato juice, cabbage juice or turnip cabbage juice)
- dactyls (a great source of potassium)
- cocoa (enriches drinks with magnesium)
When preparing homemade isotonic drinks, it’s a good idea to use fluids that naturally contain large amounts of electrolytes. Highly mineralised water is rich in magnesium and calcium. Milk contains large amounts of potassium and calcium. Plant-based drinks are a source of magnesium, calcium and sodium. Coconut water, on the other hand, contains potassium.
Protein in a homemade isotonic drink
The presence of dissolved amino acids improves the hydrating potential of a drink as well. That is why skimmed milk has a better beverage hydration index (BHI) than water. Any fluids that contain protein are good for hydrating the body. Ideal supplements to water are: skimmed milk, buttermilk, kephir, plant-based drinks with the highest protein content (with soya milk occupying the first place), and protein cocktails. Although added protein isn’t necessary to compose a homemade isotonic drink, it enhances its properties.
Carbohydrates in a homemade isotonic drink
Most ready-made isotonic drinks found in shops are also rich in carbohydrates. Added glucose does enhance water retention in cells, but remember that it is an additional source of calories and sugars. If you need a homemade isotonic to support you during long and intensive exercise (>90 minutes), feel free to add some carbohydrates (fruit juice, honey, sugar). An isotonic drink usually contains about 2–6 g of carbohydrates in 100 mL. If you want a homemade isotonic that will do well for weight loss, if you have insulin resistance, or if it is needed as a daily drink, it’s better not to add any carbohydrates.
pH of a homemade isotonic drink
When you think of a homemade isotonic drink, does a mixture of water, sugar, salt and necessarily some lemon come to your mind? It’s true that lemon juice or other acidic additive is a popular ingredient of home isotonic drinks, but the purpose of adding lemon juice is only to make the drink more tasty. The amount of lemon juice is too low to deliver any significant electrolytes. Making a hydrating drink more acidic doesn’t carry any deeper meaning; it does not affect the hydrating properties.
Homemade isotonic drinks may be sour or not; this is a matter of preference. If you’re an athlete and use isotonic drinks regularly, choose the ones without high acid content to protect the enamel of your teeth.
Recipes for a homemade isotonic drink
Classical homemade isotonic drink
The most popular recipe for an isotonic drink that is effective and inexpensive. In 1000 mL, it contains approximately 400 mg of sodium and 30 g of carbohydrates. It will be effective for active people who lose significant amounts of sweat during workouts. In long-distance sport disciplines, such as cycling and jogging, you can add twice as much honey for higher carbohydrate content.
Ingredients:
- 1000 mL of highly mineralised water
- 100 mL of fresh orange or other citrus juice
- 37 g (1.5 flat tablespoons) of honey
- 1 g of salt
Preparation:
- Mix all the ingredients.
Homemade watermelon isotonic drink
A homemade watermelon isotonic drink is recommended as a hydrating drink for any healthy person. It’ll serve you well especially on a hot day, for refreshment and better fluid retention in the body. This watermelon drink delivers about 31 kcals per 100 g.
Ingredients:
- 500 g of watermelon pulp
- a handful of fresh mint
- ¼ lime
- a handful of ice cubes
- optionally: 100 g of natural yoghurt or buttermilk
Preparation:
- Remove watermelon seeds
- Put all the ingredients into a blender and mix until you get the desired consistency.
Homemade milky strawberry isotonic drink
A simple, milky strawberry cocktail can also serve as an ideal homemade isotonic drink. Minerals found in milk and strawberries are good electrolytes, while milk proteins additionally facilitate water retention in the body. Cocoa in this recipe is optional, but it supplements the isotonic cocktail with additional magnesium. The energy content of this drink is about 38 kcals per 100 g.
Ingredients:
- 500 mL of skimmed milk (0.5% fat)
- 200 g of strawberries
- 1 teaspoon of cocoa
Preparation:
- Blend all the ingredients until smooth.
Check also healthy strawberry desserts – simple recipes for those who count calories.
Home-made soya isotonic drink “Salty Caramel”
An ideal isotonic cocktail that works for active people, e.g. during intensive cycling or a whole-day mountain trip. Dactyls and bananas are a dose of potassium and well-absorbable carbohydrates (about 8.5 g per 100 mL). Soya milk is a carrier of water and proteins, and the addition of salt increases the osmolarity of the isotonic drink. The energy content of this drink is about 60 kcals per 100 g.
Ingredients:
- 600 mL of soya milk
- 3 dactyls
- one banana
- pinch of salt
Preparation:
- Put the dactyls into a blender and add a little bit of soya milk. Blend carefully until smooth.
- Add the remaining ingredients and blend again to obtain a smooth isotonic cocktail.
Who will benefit most from homemade isotonic drinks? How to choose one for yourself?
Although homemade isotonic drinks are cheap and easy to prepare, and they hydrate better than water, not everyone will benefit from using them. These drinks are useful mainly for people who seek ideal hydration, but cannot reach it with only water for some reason. The main purpose of isotonic drinks is to:
- protect the body from excessive fluid loss
- replenish electrolyte deficiencies that occur due to increased physical effort or high external temperature
- deliver carbohydrates
The main reason for using isotonic drinks is an intensive effort that causes excessive loss of sweat. Water loss is also intensified by physical activity at higher temperature, e.g. jogging on a hot day, whole-day marching or physical work at a construction site. In that case, homemade isotonic drinks are highly indicated. You can use them as needed, when the necessity arises. You don’t have to follow any permanent protocol of isotonic supplementation to make these drinks work.
Isotonic drinks are recommended for people with intensive physical effort lasting >90 minutes or for those who pursue competitive sports, such as marathon or triathlon athletes. Shorter forms of exercise, lasting not more than 60 minutes (Zumba, strength training, swimming) are not indications to use isotonic drinks. In these cases, it is better to have water.
The ingredients of an isotonic drink can be adjusted to individual needs:
- isotonic drinks rich in sodium are good for people who lose a lot of sweat
- light fruit-based isotonic drinks (e.g. home-made watermelon cocktail) can be used during heatwaves as a hydrating fluid, next to water
- isotonic drinks with greater carbohydrate content (glucose, fructose, maltose, sucrose, maltodextrin) are intended for athletes during strenuous workouts to replenish lost sugars.
Isotonic drinks (both those found in stores and homemade) should not be used by individuals with kidney problems. Also, it’s not a good idea to use them when you’re trying to lose weight: a portion of carbohydrates is not a positive factor in this case.
Home isotonic drinks are mostly dedicated to all athletes that have intensive workouts and to physically active individuals. They replenish lost electrolytes and retain water in the body. Individuals that aren’t particularly active can also take benefit of isotonic drinks during heatwaves, but if you’re an amateur athlete, and your workouts last no longer than 90 minutes, you don’t have to use these drinks on a daily basis.
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References:
1. Millard-Stafford M, Snow TK, Jones ML, Suh H. The Beverage Hydration Index: Influence of Electrolytes, Carbohydrate and Protein. Nutrients. 2021 Aug 25;13(9):2933. doi: 10.3390/nu13092933. PMID: 34578811; PMCID: PMC8465972.
2. Rowlands DS, Kopetschny BH, Badenhorst CE. The Hydrating Effects of Hypertonic, Isotonic and Hypotonic Sports Drinks and Waters on Central Hydration During Continuous Exercise: A Systematic Meta-Analysis and Perspective. Sports Med. 2022 Feb;52(2):349-375. doi: 10.1007/s40279-021-01558-y. Epub 2021 Oct 30. PMID: 34716905; PMCID: PMC8803723.
3. García-Berger D, Mackay K, Monsalves-Alvarez M, Jorquera C, Ramirez-Campillo R, Zbinden-Foncea H, Castro-Sepulveda M. Effects of skim milk and isotonic drink consumption before exercise on fluid homeostasis and time-trial performance in cyclists: a randomized cross-over study. J Int Soc Sports Nutr. 2020 Mar 30;17(1):17. doi: 10.1186/s12970-020-00346-9. PMID: 32228635; PMCID: PMC7106740.