A plain-English reference for the terms that show up across hydration product labels, marketing copy, and our articles. Jump to a letter:

A B C D E F G H I M N O P S T V W

A

ACSM
American College of Sports Medicine. The professional body that publishes sports-science guidance widely referenced in hydration and exercise nutrition research. Their hydration position statements are the standard reference for in-session fluid and electrolyte recommendations.
Allulose
A rare sugar found naturally in small amounts in some fruits. About 70% as sweet as sucrose with negligible caloric absorption. Used as a sweetener in some sugar-free electrolyte products including the Sugar-Free Liquid I.V. line.

B

Bicarbonate
A negatively-charged electrolyte (HCO3-) that acts as a buffering agent in the blood, helping the body manage the acid produced during hard exercise. Included in some performance-targeted products for short, high-intensity efforts.

C

Calcium
An electrolyte involved in muscle contraction at the cellular level. Sweat losses are small. Some sports drinks (notably Powerade ION4) include calcium alongside the other electrolytes. More detail here.
Carbohydrate
The macronutrient sports drinks deliver as in-session fuel. Standard isotonic drinks sit at 6-8% carbohydrate by mass; daily-hydration products carry less. Endurance products can deliver 80+ g/hour for trained athletes.
Chloride
An electrolyte that travels with sodium in the body. The second-most-lost mineral in sweat after sodium. Most sodium-containing electrolyte products include chloride as part of the sodium pairing - it's typically not called out separately. More detail here.

D

Dehydration
A state of insufficient body fluid. Mild dehydration (1-2% of body mass) measurably affects cognitive performance and physical effort; severe dehydration is a clinical concern. The body normally manages fluid balance through thirst and urine output.

E

Electrolyte
A mineral that carries an electrical charge when dissolved in water. The main electrolytes in the body are sodium, chloride, potassium, magnesium, calcium, bicarbonate, and phosphate. They drive nerve and muscle signalling and regulate fluid balance.

F

FSANZ
Food Standards Australia New Zealand. The regulatory body that sets food labelling, ingredient, and safety standards for Australia and New Zealand. The Nutrition Information Panel format on Australian product labels follows FSANZ rules.

G

Glucose
A simple sugar that the body uses as a primary energy source. The most common carbohydrate in sports drinks alongside sucrose and (increasingly) fructose.
Glucose-Fructose Blend
A combination of glucose and fructose used in some endurance products. Because the gut uses different transport pathways for glucose-derived carbs and fructose, combining them lets athletes absorb more total carbohydrate per hour - typically up to 90 g/hour for trained athletes.

H

HASTA
Human and Supplements Testing Australia. An Australian sports-supplement testing program that screens products for WADA-prohibited substances. Carrying HASTA certification is one signal Australian athletes subject to in-competition testing look for. Sodii is one example of a HASTA-certified electrolyte brand.
Heat Acclimatisation
The body's adaptation to repeated heat exposure over 7-14 days. Adaptations include plasma volume expansion, earlier sweating onset, higher peak sweat rate, and reduced sweat sodium concentration. More detail here.
Hypertonic
A drink with a higher dissolved-particle concentration than blood. Concentrated fruit juices and many soft drinks are hypertonic. They tend to absorb slower and sit heavier in the stomach during exercise.
Hyponatremia
Low sodium concentration in the blood. Exercise-associated hyponatremia (EAH) is documented in endurance research, particularly among slower marathoners and ultramarathon participants who drink large volumes of plain water during events. Modern guidance favours drinking to thirst with sodium-containing drinks. More detail here.
Hypotonic
A drink with a lower dissolved-particle concentration than blood. Lower-carbohydrate electrolyte tablets and oral rehydration solutions are typically hypotonic - they absorb fast and prioritise fluid replacement over fuelling.

I

Isotonic
A drink with roughly the same dissolved-particle concentration as blood. Classic sports drinks (~6-8% carbohydrate) sit in this band. The textbook profile for in-session fuel + fluid + electrolytes. More detail here.

M

Magnesium
An electrolyte involved in hundreds of enzymatic reactions including energy metabolism and muscle function. Sweat losses are small. Endura and Staminade are two Australian brands that emphasise magnesium in their formulations.
Maltodextrin
A carbohydrate derived from starch (typically corn, rice, or wheat). A chain of glucose molecules that digests into glucose. Used in endurance products because it's much less sweet than table sugar, letting brands deliver more carbohydrate without overpowering sweetness. More detail here.
Monk Fruit
A plant-derived non-nutritive sweetener (luo han guo) used in some sugar-free electrolyte products. Often blended with stevia for flavour rounding.

N

NHMRC
National Health and Medical Research Council. The Australian government body that publishes the Australian Dietary Guidelines and nutrient reference values. Their adequate intake values for water, sodium, and other minerals are the standard Australian reference.

O

Oral Rehydration Solution (ORS)
A formulation of water, glucose, sodium, and potassium in carefully chosen ratios for rapid rehydration during fluid loss. Endorsed by the World Health Organization in the late 1970s and used widely in clinical and travel contexts. Hydralyte and Pedialyte are consumer brands built around ORS principles.
Osmolality
The measure of dissolved particle concentration in a solution. The term sports scientists use when describing whether a drink is hypotonic, isotonic, or hypertonic relative to blood plasma.

P

Plasma Volume
The volume of fluid in the bloodstream. Heat acclimatisation expands plasma volume over 7-14 days, which improves cardiovascular efficiency during heat stress.
Potassium
An electrolyte concentrated mostly inside cells (sodium is mostly outside). Together they drive the electrical gradient that lets nerves fire and muscles contract. Sweat losses are smaller than sodium but real.

S

Sodium
The most-lost electrolyte in sweat, by a clear margin. Sweat sodium concentration varies between individuals from 200 mg/L up to 1,500+ mg/L. The variable with the widest spread between electrolyte products. More detail here.
Sodium-Glucose Co-Transport
The intestinal mechanism (SGLT-1) that pulls sodium and glucose into the bloodstream together, with water following by osmosis. The underlying principle of oral rehydration solutions and many sports drinks. More detail here.
Stevia
A plant-derived non-nutritive sweetener (from the stevia plant). Zero calories. Used in many sugar-free electrolyte products including LMNT and Nuun. Some people perceive a slight aftertaste.
Sucralose
A synthetic non-nutritive sweetener (sold as Splenda) about 600x sweeter than sugar. Used in many sugar-free sports drinks including Gatorade Zero and Powerade Zero. Clean taste profile for most people.
Sweat Rate
Volume of sweat produced per unit time, typically expressed as litres per hour. Typical sport-context rates are 0.5-1.5 L/hour; hot-climate athletes can exceed 2 L/hour. Sweat rate is largely separate from sweat composition.

T

TGA
Therapeutic Goods Administration. The Australian government body that regulates therapeutic claims and goods. Claims like 'treats X', 'prevents Y', or 'reduces the risk of Z' are TGA-regulated and may only be made by registered therapeutic goods within their registration scope. Hydrate Better does not make TGA-regulated therapeutic claims.
Tonicity
How a drink's dissolved-particle concentration compares to blood. Isotonic matches blood; hypotonic is lower; hypertonic is higher. More detail here.

V

Vasopressin
Also known as antidiuretic hormone (ADH). The hormone the body releases to retain water by signalling the kidneys to reabsorb fluid. Part of the body's thirst and fluid-balance regulation system.

W

WADA
World Anti-Doping Agency. Maintains the list of substances and methods prohibited in Olympic and many professional sports. HASTA certification screens supplement ingredients against the WADA prohibited list.
WHO
World Health Organization. Their oral rehydration solution (ORS) framework, formalised in the late 1970s, is the public-health basis for rehydration products like Hydralyte and Pedialyte.