Energy drink
An energy drink is a beverage marketed to increase alertness or energy, typically through caffeine and often sugar or other stimulants.
Caffeine: A naturally occurring stimulant that blocks adenosine receptors and can temporarily reduce feelings of fatigue. It is the main stimulant in most energy drinks.
Caffeine intoxication: A harmful state caused by excessive caffeine, with symptoms such as agitation, tremor, nausea, or rapid heartbeat. Large or repeated servings can push caffeine intake toward toxic levels.
Cardiovascular effects of caffeine: Changes in heart rate and blood pressure associated with caffeine consumption. Energy drinks can produce noticeable cardiovascular effects, especially at high doses.
Sports drink: A beverage designed to replace fluids and electrolytes, often with carbohydrates, during or after exercise. Its primary purpose is hydration, unlike an energy drink’s stimulant-based alertness claim.
Adenosine: A signaling molecule whose buildup in the brain contributes to sleep pressure. Caffeine’s blockade of its receptors helps explain energy drinks’ alerting effect.
Energy drink and alcohol: The combined consumption of caffeinated energy drinks and alcoholic beverages. Caffeine may reduce perceived sleepiness without reducing alcohol-related impairment.
Adolescent caffeine use: Caffeine consumption among teenagers, a group for whom health authorities advise particular caution. Energy drinks are widely marketed to young people despite concerns about sleep and stimulant exposure.
Coffee: A brewed beverage made from roasted coffee beans and commonly consumed for its caffeine. Coffee delivers caffeine without the standardized branding and typical ingredient mix of energy drinks.
Sugar: A class of sweet-tasting carbohydrates that includes glucose and sucrose. Many energy drinks supply sugar, which adds calories but does not reproduce caffeine’s receptor effects.
Sports nutrition: The study and practice of nutrition strategies that support athletic training and performance. Some athletes use energy drinks for caffeine, though they are not equivalent to hydration products.