Tonicity: what does hypotonic, isotonic and hypertonic mean? (2023)

It sounds easy. You sweat when you exercise. During intense or prolonged exercise, you sweat more¹. Sweat is made up of water and electrolytes, such as B. Salt, so that as you exercise, your body gradually depletes its supply of them. Hence aSportdrinkof water and electrolytes would be an advantageous solution to support both performance and rapid hydration².

Since the 1980's, athletes have been primed to stay ahead of the thirst using specially made formulas that have since fueled a market driven by themthe importance of fluid replacement. Years later, the sports drink industry has a lot going for it, but it's important to understand the three different types of sports energy drinks: hypotonic, isotonic, and hypertonic.

The main difference between hypotonic, isotonic and hypertonic solutions is that isotonic solutions are solutions with equal osmotic pressure whereas hypotonic solutions are solutions with lower osmotic pressure and hypertonic solutions are solutions with high osmotic pressure.

A brief explanation of tonicity is required to understand the key differences³. Simply put, a drink's tonicity measures the concentration of sugars and salts compared to the concentration in the human body, primarily in your blood.

What is hypotonic?

A hypotonic solution has low tonicity. It has a lower concentration of salts and sugars in solutes than blood and is therefore absorbed more quickly.

When a solution, in this case water, has a lower concentration of salts and sugars than the concentration of a cell, say a red blood cell, the osmotic pressure is lower -Osmotic pressure is the pressure that must be applied to prevent this movement of solutes across the semipermeable membrane (a biological or synthetic membrane that allows molecules and ions to pass through). This movement is often referred to as osmotic flow.

The result of the above is a net movement of water into the cell, causing it to swell and eventually rupture (plasmolysis). This type of explosion tries to equalize the concentration of the cell's inside and outside solutions.In this case, the osmotic pressure that must be applied to stop the movement is less - easier movement at a faster speed.

The need for this web movement is to reach a state of equilibrium; Every system, in this case the human body, needs balance to function optimally.

(Video) Hypotonic, isotonic, and hypertonic solutions (tonicity) | Khan Academy

Traditionally, salt and sugar have served to preserve food by destroying the microorganisms that contribute to food spoilage; But when you look at a hypotonic solution and its lower concentration of salt and sugar, this type of solution does not help in preserving food.

Conclusion: Hypotonic solution promotes osmotic flowinthe cell with low osmotic pressure.

what is hypertonic

A hypertonic solution has a high tonicity. It has a higher salt and sugar concentration of solutes than blood.

Compared to a hypotonic solution, a hypertonic one attempts to rebalance a cell's concentration with its environment. In this case, the osmotic pressure is higher - due to a higher concentration of solutes - which allows the solutes to move along a concentration gradient (from high concentration to low concentration). When a solution is hypertonic, it can cause cells to shrink and shrink — the result of net movement out of the cell across the semipermeable membrane.

Hypertonic solutions are used to preserve food due to their higher salt and sugar concentration of solutes. For example, fish is often soaked or packaged in a hypertonic solution to kill microbes that may be present in the environment in which the fish is kept. This is because microbial cells contain a higher amount of water than solutes compared to the water content in a hypertonic solution. The lack of water causes the cells to shrink and eventually kill the microbes.

Conclusion: Hypertonic solution promotes osmotic flowout ofthe cell.

What is isotonic?

The definition of isotonic is a solution that contains the same concentration of water and solutes, such as salt.

When the solute concentrations are equal between the interior of the cell and the surrounding environment, there is no net gain or loss of water from the cell. Such a situation is called isotonic.

And because the solute concentrations are the same, such isotonic solutions are not suitable for food preservation.

(Video) IV fluid tonicity: Isotonic solutions, Hypotonic solutions, and Hypertonic solutions

Conclusion: isotonic solution promotesNOosmotic flow (due to equal osmotic pressures).

sports drinks

Tonicity: what does hypotonic, isotonic and hypertonic mean? (1)

Sports drinks, also known asElectrolyte drink, help athletes replenish water, electrolytes and energy before, during and after exercise.

The main components of sports drinks are water, carbohydrates and electrolytes. Each contributes to a person's performance, recovery and overall hydration. While water is great for short-term or moderate exertion, such as at the gym, the combination of water and electrolytes in a sports drink can help people replace and replenish what is normally lost through sweat — water and electrolytes — and therefore are more suitable for people with a higher level of training, fitness and exertion.

Let's take a closer look at how hypotonic, isotonic, and hypertonic solutions apply to sports drinks.

How do hypotonic sports drinks work?

Tonicity: what does hypotonic, isotonic and hypertonic mean? (2)

Simply put, the liquids in a hypotonic sports drink are typically absorbed more quickly into the bloodstream due to their lower solute concentration and zero amounts of carbohydrates per unit volume.

How a hypotonic sports drink works is when water flows from a lower solute concentration, such as the gut, to an area of ​​higher concentration, such as the blood, the osmotic flow is faster and easier, which subsequently promotes faster hydration.

Hypotonic drinks are therefore best for fast hydrationinstead of supplying large amounts of energy.

(Video) Hypertonic, Hypotonic and Isotonic Solutions!

How do hypertonic sports drinks work?

Formulated with lots of carbohydrates, hypertonic sports drinks are more concentrated than your blood - the best option for individuals looking for a drink to support high-intensity activity.

When a hypertonic solution ends up in your gut, the body has to draw water from the bloodstream to dilute the solutes so the nutrients can be reabsorbed into the gut wall, giving you the energy you need.

Hypertonic drinks are best for getting calories into the body as quickly as possible.

How do isotonic sports drinks work?

Most traditional sports drinks fall under the isotonic category - they provide a reasonable amount of energy and cleanse the colon fairly quickly. They typically provide 1.5 to 2x more carbs than a hypotonic sports drink and therefore can behave similarly to hypertonic drinks, but are often preferred as a "watered down" version.

Isotonic drinks are best for short-term workouts with a preference for energy.

How to find the best sports drink for you

From personal preferences to the type of exercise or activity you engage in, there are many factors to consider when choosing a suitable sports drink.

Tonicity: what does hypotonic, isotonic and hypertonic mean? (3)

type of activity
The type of sport or training plays a role in which sports drink is suitable for you. For example, if you're planning a light jog, you might choose a drink that can be consumed both before and after your workout, while a higher-intensity sport might be a drink that provides optimal energy.

Personal preferences
Flavor is just as important as natural ingredients, effervescence, and even added caffeine. Keep training or training, just swap out the drinks. Don't worry about personalizing your drink — andBottle– to the sport of your choice.

(Video) Osmosis and Tonicity

If it's warm or even hot, you'll sweat. So you can trade a lot of energy for an electrolyte-rich option to—quickly—replenish what you lose through sweating.


A properly formulated sports drink plays a valuable role in training and performance¹, but when choosing the right sports drink, it's important to figure out what you want and need from it. Is it energy, hydration, or both? The definitions of hypotonic, isotonic, and hypertonic can be used as benchmark insight into sports drinks, but be prepared to experiment based on factors such as activity, performance, exercise duration, and sweat level.

¹david s.Rowlands, Brigitte Hani Kopetschny und Claire E. Badenhorst (2002) „The Hydrating Effects of Hypertonic, Isotonic and Hypotonic Sports Drinks and Waters on Central Hydration While Continuous Exercise: A Systematic Meta-Analysis and Perspective.“,Sports Med, Volume 52, pages 349-375.

²R.J. Maughan (1998) "The Sports Drink as a Functional Food: Formulations for Successful Performance",Procedures of the food society, Volume 57, pages 15-23

³Predrag Vujovic,Michael Chirillo, AndDee U. Silverthorn(2018) "Learning (through) osmosis: an approach to teaching osmolarity and tonicity",Advances in physiology education.

AB Lemmey, R.G. Eston, S.C. Moloney and J.W. Yeomans (2000) "Effects of hydration state and rehydration method on bioelectrical impedance analysis",South African Journal of Sports Medicine, Volume 7, Issue 1, Pages 8-12.

Prixit Guleria, Parveen Chand, Amit Kaushik and Sapna Dhawan (2018) "Role of nutrients and sports drinks on athletic performance: A review",International Journal of Physiology, Nutrition and Physical Education, Volume 3, Issue 1, Pages: 184-189.

Nadia Bashir, Monika Sood und Julie D. Bandral (2020) „Food Preservation by Osmotic Dehydration – A Review“,Chemical Science Review and Letters, Volume 9, Issue 34, Pages 337-341.

Prixit Guleria, Parveen Chand, Amit Kaushik and Sapna Dhawan (2018) "Role of nutrients and sports drinks on athletic performance: A review",International Journal of Physiology, Nutrition and Physical Education, Volume 3, Issue 1, Pages: 184-189.

(Video) Tonicity: Hypertonic, Hypotonic, and Isotonic Solutions

Prixit Guleria, Parveen Chand, Amit Kaushik and Sapna Dhawan (2018) "Role of nutrients and sports drinks on athletic performance: A review",International Journal of Physiology, Nutrition and Physical Education, Volume 3, Issue 1, Pages: 184-189.

Darrell L. Bonetti, Will G. Hopkins, Matthew R. Wood, Jennifer Doyle und Elizabeth Fox (2007), „The Effect of Consumption of Four Drinks on Endurance Performance and Physiology“,12th Annual Congress of the European College of Sports Science, Finland, 11-14 July 2007.Available at: pdf(Accessed October 21, 2022)

¹Susan M Shirreffs (2009) "Hydration in Sport and Exercise: Water, Sports Drinks and Other Beverages",British Nutrition Foundation, Volume 34, Issue 4, Pages 374-379.


What are the 3 types of solution tonicity? ›

Three terms—hypertonic, hypotonic, and isotonic—are used to describe whether a solution will cause water to move into or out of a cell: If a cell is placed in a hypertonic solution, there will be a net flow of water out of the cell, and the cell will lose volume.

How do you remember isotonic hypertonic and hypotonic? ›

But let's break down IV solution memorization even more.
  1. Skinny is for Hypertonic Fluids.
  2. Hippo is for Hypotonic Fluids.
  3. I-so-perfect is for Isotonic Fluids.
Jan 8, 2018

What is the tonicity of isotonic solution? ›

The tonicity of a solution is related to its effect on the volume of a cell. Solutions that do not change the volume of a cell are said to be isotonic. A hypotonic solution causes a cell to swell, whereas a hypertonic solution causes a cell to shrink.

How do you explain tonicity? ›

Tonicity is defined as the ability of a solution surrounding a cell to cause that cell to gain or lose water (Urry et al., 2017). While osmolarity is an absolute quantity, tonicity is relative.

Does hypotonic shrink or swell? ›

A hypertonic solution has increased solute, and a net movement of water outside causing the cell to shrink. A hypotonic solution has decreased solute concentration, and a net movement of water inside the cell, causing swelling or breakage.

Is hypotonic in or out? ›

A hypotonic tonic solution is any external solution that has a low solute concentration and high water concentration compared to body fluids. In hypotonic solutions, there is a net movement of water from the solution into the body.

What are the 3 main types of IV fluids? ›

There are three types of IV fluids:
  • Isotonic.
  • Hypotonic.
  • Hypertonic.
Jun 18, 2021

Is water Hypertonic or hypotonic? ›

If a cell encounters a hypotonic environment, (like pure water for instance), water will diffuse into the cell and the cell will begin to swell. This can of course lead to an explosion of sorts.

What is hypotonic for dummies? ›

A hypotonic solution has a lower solute concentration than inside the cell (the prefix hypo is Latin for under or below). The difference in concentration between the compartments causes water to enter the cell. Plant cells can tolerate this situation better than animal cells.

What is a hypotonic solution? ›

Hypotonic Solution Definition

Hypotonic solution refers to a solution containing a lower amount of solute in comparison to the solute concentration in other solutions, across a semipermeable membrane. Such a solution has a decreased solute concentration and a total movement of water in the cell.

What is a hypertonic solution? ›

Hypertonic solution: A solution that contains more dissolved particles (such as salt and other electrolytes) than is found in normal cells and blood. For example, hypertonic solutions are used for soaking wounds.

What is an example of hypotonic? ›

Hypotonic solutions have a lower concentration of dissolved solutes than blood. An example of a hypotonic IV solution is 0.45% Normal Saline (0.45% NaCl). When hypotonic IV solutions are infused, it results in a decreased concentration of dissolved solutes in the blood as compared to the intracellular space.

Is pure water hypotonic? ›

In the present case, pure water will act as a hypotonic solution. The hypotonic solution is a solution that contains a lesser number of solutes in comparison to that of the surrounding solution.

What is an example of an isotonic solution? ›

Common examples of isotonic solutions are 0.9% normal saline and lactated ringers. These fluids are useful when the patient has lost fluid volume from blood loss, trauma, or dehydration due to excessive nausea/vomiting or diarrhea.

What is tonicity with example? ›

EXAMPLES. Tonicity is the reason why salt water fish cannot live in fresh water and vice versa. A salt water fish's cells have evolved to have a very high solute concentration to match the high osmolarity of the salt water they live in.

Is gaining water hypertonic? ›

The process of water moving through a semipermeable membrane is called osmosis. An organisms whose contents were hypertonic to the environment would gain water; one that was hypotonic to the environment would lose water.

Does hypertonic mean lose water? ›

Hypertonic dehydration occurs when an individual loses water while retaining a high concentration of electrolytes, or sodium, causing an imbalance within the body.

Is losing water hypotonic? ›

Hypotonic dehydration is loss of water associated with decreased effective osmolality of body fluids. Causes include loss of isotonic fluids via the kidneys or gastrointestinal tract that has been partially compensated by drinking hypotonic fluids (eg, unsweetened tea or plain water).

What liquids are hypotonic? ›

Some examples of hypotonic solutions include anything that has more water and less solute compared to the cells:
  • Distilled water.
  • 0.45% saline.
  • 0.25% saline.
Apr 30, 2015

Is an IV hypertonic or hypotonic? ›

Colloids are IV fluids that contain solutes of high molecular weight, technically, they are hypertonic solutions, which when infused, exert an osmotic pull of fluids from interstitial and extracellular spaces. They are useful for expanding the intravascular volume and raising blood pressure.

How do you identify hypertonic and hypotonic? ›

In comparing two solutions of unequal solute concentration, the solution with the higher solute concentration is hypertonic, and the solution with the lower solute concentration is hypotonic.

What are the 4 main types of IV fluids? ›

The 4 main types of IV fluids include:
  • Normal Saline.
  • Half Normal Saline.
  • Lactated Ringers.
  • Dextrose.

Is D5W isotonic or hypotonic? ›

D5W is unique. It can be categorized as an isotonic solution or a hypotonic solution. The amount of dextrose in the solution makes its tonicity, or solute concentration, similar to that of intravascular fluid, making it isotonic. It also provides free water, following the metabolism of the dextrose.

Is rain water hypotonic? ›

Rainwater acts as a hypotonic solution to keep plants sufficiently hydrated. Rainwater has a lower concentration of solutes than the plant cell's cytosolic fluid, so rainwater is hypotonic compared to the cytosolic fluid within plant cells.

What type of fluid is hypertonic? ›

Hypertonic fluids contain a higher concentration of solute compared to plasma and interstitial fluid; this creates an osmotic gradient and drives fluid from the interstitial space into the intravascular space.

Is hypertonic in or out? ›

Hypertonic refers to a solution with higher osmotic pressure than another solution. In other words, a hypertonic solution is one in which there is a greater concentration or number of solute particles outside a membrane than there are inside it.

What is a simple definition of hypertonic? ›

: having a higher osmotic pressure than a surrounding medium or a fluid under comparison.

What happens during hypotonic? ›

In a hypotonic solution, the solute concentration is lower than inside the cell. The prefix hypo means under or below in Latin. Under these conditions, the osmotic pressure gradient forces water into the cell. Depending on the amount of water that enters, the cell may look enlarged or bloated.

What is isotonic simple? ›

Isotonic is a term used to describe solutions and chemistry and, sometimes, muscles in human biology. In chemistry, a solution is said to be isotonic when it has the same concentration of solutes as another solution across a semipermeable membrane. The use of isotonic in human anatomy is used more rarely.

What are the 3 types of solution? ›

What are the 3 types of solutions? Solid solution, Liquid solution, Gaseous solution.

Is hypertonic water or salt? ›

Any solution of sodium chloride (NaCl) in water with a concentration of NaCl higher than that found in physiological saline (0.9% w/v).

What is a real life example of hypertonic? ›

Seawater. Seawater has a high amount of salt particles compared to freshwater, making it a hypertonic solution. Freshwater fish can't live in seawater because the water would rush from their cells into the surrounding saltwater. They would soon die from dehydration.

Can you drink hypotonic water? ›

When you drink a hypotonic drink the solution moves via osmosis across the gut walls and into the blood vessels. This means fast rehydration, as the drink is rapidly absorbed across the gut lining and quickly replaces fluids lost.

Can I drink distilled water? ›

Distilled water is safe to drink. But you'll probably find it flat or bland. That's because it's stripped of important minerals like calcium, sodium, and magnesium that give tap water its familiar flavor. What's left is just hydrogen and oxygen and nothing else.

What are the 3 types of osmosis? ›

The three types of osmotic conditions include- hypertonic, isotonic, and hypotonic.

What are 3 hypertonic solutions? ›

Hypertonic Solutions
TypeIV Solution
Hypotonic0.45% Sodium Chloride (0.45% NaCl)
Hypotonic5% Dextrose in Water (D5W)
Hypertonic3% Sodium Chloride (3% NaCl)
Hypertonic5% Dextrose and 0.45% Sodium Chloride (D50.45% NaCl)
4 more rows

What are three types of solutions? ›

Depending upon the dissolution of the solute in the solvent, solutions can be categorized into supersaturated solution, unsaturated and saturated solutions.

What are the three types of solutions in biology? ›

There are three different types of solutions:
  • Isotonic Solution.
  • Hypertonic Solution.
  • Hypotonic Solution.

What are the three types of solution in chemistry? ›

What are the 3 types of solutions? Solid solution, Liquid solution, Gaseous solution.

What is an example of isotonic fluid? ›

Common examples of isotonic solutions are 0.9% normal saline and lactated ringers. These fluids are useful when the patient has lost fluid volume from blood loss, trauma, or dehydration due to excessive nausea/vomiting or diarrhea.


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