Comparing the Electrolyte Composition of Popular Sports Drinks

Authors: Ethan Castellino, Ryan Su

This Exemplar will teach the following concept(s) from the ACS Examinations Institute General Chemistry ACCM:

IV. D. 3. a. Calculations using molarity of solutions—including determination of molarity, making a solution of known molarity, and reaction stoichiometry of solutions—are key quantitative skills. 

Sports drinks were first introduced so that athletes who were in practice for multiple hours and only had water would experience less cramping and dehydration. Today, these drinks, most notably Gatorade, Powerade, and BODYARMOR (BA), are not just popular among collegiate and professional athletes. They are also popular among the general population. These drinks contain chemical substances that leave consumers feeling more hydrated and improve their athletic performance: electrolytes.

Electrolytes are substances that dissociate into ions when dissolved in water, such as table salt (NaCl). They are vital in our bodies as they help with cell signaling and maintain the balance of water in cells. Firstly, our bodies use electrical signals to control our muscles. Importantly, our neurons and muscles use a signaling pathway that utilizes electrolytes as the method to conduct a current in order to contract and relax our muscles.⁶ These electrical signaling pathways are not only vital when humans do physical exercise, but also paramount in the regular functioning of our organs and tissue.

When you workout, your body loses many electrolytes, as they come out through your sweat. Electrolytes work by having “a natural positive or negative electrical charge when dissolved in water."³ Strong electrolytes dissolved in water will create a solution that conducts an electric current efficiently.⁸ A great example of an electrolyte solution is salt water. The positive charge of sodium and negative charge of chlorine balance each other out.³ Because NaCl is an ionic compound and is very polar, and because water is also polar, when salt is put in water, it dissociates quickly. This goes in line with the theory that like dissolves like. The dissociation of NaCl in H2O can be seen in Fig 1. The crystal lattice structure of the sodium salt, when added into water, creates a sodium cation surrounded by negative dipoles of water molecules and a chlorine anion surrounded by positive dipoles of water molecules.

 

Figure 1: Diagram of the dissociation of salt in water (Reprinted with permission from OpenStax College (2013). Copyright 2013 CNX and Rice University. https://commons.wikimedia.org/wiki/File:214_Dissociation_of_Sodium_Chloride_in_Water-01.jpg#filehistory.)

 

Our bodies also use electrolytes such as Na+ and K+ in order to maintain the balance and flow of water in cells.² This is because electrolytes act as very common solutes in our bodies, and our cells can utilize these electrolytes to create chemical gradients. Through the process of osmosis, which is the spontaneous net diffusion of solvent molecules through a selectively-permeable membrane from a region of low solute concentration to high solute concentration, water tends to “follow” the flow of solutes.¹ In our bodies, enzymes can change the relative concentrations of electrolytes on either side of a membrane in order to influence the movement of water to one side of the membrane, or even to help in other pathways where other molecules are transported in and out a cell. For example, a specific pathway in cells utilizes a sodium-potassium pump enzyme in order to promote the transport of glucose, a source of cellular energy, into a cell.¹

 

Figure 2: Gatorade Thirst Quencher nutrition label and ingredients list (Reprinted with permission from Jay Dyer (2019). Copyright 2019 Lacrosse Strength and Conditioning. https://lacrossesc.com/hydrating-for-optimal-lacrosse-performance/.)

 

Figure 3: Powerade nutrition label (Reprinted with permission from Walmart. https://www.walmart.com/ip/POWERADE-Mountain-Berry-Blast-ION4-Electrolyte-Enhanced-Fruit-Flavored-Sports-Drink-w-Vitamins-B3-B6-B12-Replenish-Sodium-Calcium-Potassium-Magnesium/16224467.) 

Figure 4: BODYARMOR nutrition label and ingredients (Reprinted with permission from Amazon. https://www.amazon.com/Body-Armor-Super-Drink-Variety/dp/B01187P7EM.)

 

Electrolytes Present In Major Sports Drinks

Gatorade Thirst Quencher	Powerade	BODYARMOR (BA)
160 mg Sodium (citric acid, salt, sodium citrate)	150 mg Sodium (citric acid, salt)	40 mg Sodium (citric acid, salt not listed)
45 mg Potassium (monopotassium phosphate)	35 mg Potassium (monopotassium phosphate)	700 mg Potassium (coconut water concentrate, dipotassium phosphate)
X	Magnesium (magnesium chloride)	Magnesium (magnesium oxide)
X	Calcium (calcium chloride)	Calcium (calcium d-pantothenate)
X	X	Zinc (zinc oxide)

Table 1: List of electrolytes present in major sport drinks (standardized to 16 oz serving size)^5,7

The first major electrolyte in sports drinks is sodium. Gatorade and Powerade have very similar sodium composition, but BA has a lot less salt and overall sodium composition, as 160/150 mg > 40 mg. BA says they use less sodium because normal sports drinks use sodium as their key electrolyte. However, most Americans tend to consume an excess of sodium via their food consumption and do not consume enough potassium. Too much sodium can cause high blood pressure and potassium helps to lower blood pressure.⁴ Instead, BA uses potassium as its primary electrolyte. This is very obvious in Table 1, which shows that, while Gatorade and Powerade have 45 mg or 35 mg potassium respectively, BA has an overwhelming 700 mg. BA claims they use a lot of potassium because it is extremely important in the hydration process by helping to prevent cramping.⁴ Table 1 also shows that Powerade and BA both have Magnesium and Calcium, and BA has Zinc, but these are present mostly to reach daily requirements for these nutrients. As electrolytes, their effect is negligible in humans compared to the major electrolytes: sodium and potassium.

 

Sample Problem #1

As described in the table above, for a 16 oz. drink the amount of sodium in Gatorade is 160mg. For Powerade it is 150mg of sodium and BODYARMOR has 40mg of sodium. Find and compare the concentration (moles/liter) of sodium in the the three drinks. (1 oz. = 29.57ml)

 

Solution:

Na⁺ molar mass = 22.99 g/mol

For Gatorade:

$$
\frac{160 \mathrm{mg}}{16 \mathrm{oz.}} \times \frac{10^{-3} \mathrm{~g}}{1 \mathrm{mg}} \times \frac{1 \mathrm{~mole}}{22.99 \mathrm{~g}} \times \frac{1 \mathrm{oz.}}{0.02957 \mathrm{~L}}=0.0147 \mathrm{M}
$$

For Powerade:

$$
\frac{150 \mathrm{mg}}{16 \mathrm{oz.}} \times \frac{10^{-3} \mathrm{~g}}{1 \mathrm{mg}} \times \frac{1 \mathrm{~mole}}{22.99 \mathrm{~g}} \times \frac{1 \mathrm{oz.}}{0.02957 \mathrm{~L}}=0.0138 \mathrm{M}
$$

For BODYARMOR:

$$
\frac{40 \mathrm{mg}}{16 \mathrm{oz.}} \times \frac{10^{-3} \mathrm{~g}}{1 \mathrm{mg}} \times \frac{1 \mathrm{~mole}}{22.99 \mathrm{~g}} \times \frac{1 \mathrm{oz.}}{0.02957 \mathrm{~L}}=0.0037 \mathrm{M}
$$

The concentration of sodium in Gatorade, Powerade, and BODYARMOR are 0.0147M, 0.0138M and 0.0037M, respectively. Gatorade has the highest concentration of sodium electrolytes, while Powerade has a slightly lower concentration. BODYARMOR has a significantly lower concentration of sodium, with a concentration of 0.0037M which is only a quarter of the concentration in Gatorade.

Sample Problem #2

A sports drink company would like to make a new sports drink that has electrolyte content that matches up to the top drinks in the industry. Their electrolyte content goals are: 100mg sodium and 50mg potassium per 400 ml drink. Sodium electrolytes are added into drinks through the addition of sodium citrate salt (Na3C6H5O7). Potassium electrolytes are added into drinks through the addition of monopotassium phosphate salt (KH2PO4). What is the concentration (moles/L) of sodium and potassium ions in their new drink?

 

Solution:

100mg/400ml Na^{+ c}oncentration

Na⁺ molar mass = 22.99 g/mol

$$
\frac{100 \mathrm{mg}}{400 \mathrm{ml}} \times \frac{10^{-3} \mathrm{~g}}{1 \mathrm{mg}} \times \frac{1 \mathrm{~mole}}{22.99 \mathrm{~g}} \times \frac{10^{3} \mathrm{ml}}{1 \mathrm{~L}}=0.0109 \mathrm{M}
$$

50mg/400ml K⁺ concentration

K⁺ molar mass = 39.10 g/mol

$$
\frac{50 \mathrm{mg}}{400 \mathrm{ml}} \times \frac{10^{-3} \mathrm{~g}}{1 \mathrm{mg}} \times \frac{1 \text { mole }}{39.10} \times \frac{10^{3} \mathrm{ml}}{\mathrm{L}}=0.0032 \mathrm{M}
$$

 

The concentration of Na⁺ is 0.0109M. The concentration of K⁺ is 0.0032M.

 

References

1. Allison Calabrese, C. G.; University of Hawai’i at Mānoa Food Science and Human Nutrition Program. Electrolytes important for Fluid Balance. https://pressbooks-dev.oer.hawaii.ed...fluid-balance/ (accessed Nov 11, 2022).

 

2. Electrolytes: Understanding replacement options. https://www.acefitness.org/certifiednewsarticle/715/electrolytes-understanding-replacement-options/#:~:text=Therefore%2C%20electrolytes%20play%20a%20critical,can%20be%20lost%20through%20sweating (accessed Nov 11, 2022). 

 

3. Electrolytes: Types, purpose and normal levels. https://my.clevelandclinic.org/health/diagnostics/21790-electrolytes (accessed Nov 11, 2022).

 

4. Frequently asked questions: Bodyarmor sports drink: Superior hydration. https://www.drinkbodyarmor.com/frequently-asked-questions/ (accessed Nov 11, 2022). 

 

5. Hydration Solutions For Every Occasion. https://performancepartner.gatorade.com/content/products/hydrationPortfolio.pdf (accessed Nov 11, 2022). 

 

6. Muscle Cramps and Spasms: The Electrolyte Misconnection. https://eletewater.co.uk/blogs/research/8029093-muscle-cramps-and-spasms-the-electrolyte-misconnection#.Y5Dn1XbMKz4 (accessed Dec 7, 2022).

 

7. Powerade and the Science of Hydration. https://www.powerade.co.nz/sports-hydration/powerade-and-the-science-of-hydration (accessed Nov 11, 2022).
    

8. Zumdahl, S. S.; DeCoste, D. J. In Chemical principles; Cengage Learning: Boston, MA, 2017; pp 88–90.