Western Governors University (WGU) HLTH1010 C458 Health, Fitness, and Wellness Practice Exam

Caffeine is widely recognized as a stimulant that increases both heart rate and mental alertness. It works by blocking adenosine receptors in the brain, which helps to promote wakefulness and focus. This action also leads to a temporary increase in heart rate and energy levels, making it a popular choice for individuals looking to enhance cognitive performance or combat fatigue.

Caffeine is commonly found in coffee, tea, energy drinks, and certain sodas, and is often consumed for its stimulating effects. Its influence on the central nervous system highlights its role as a short-term enhancer of both mental and physical performance, distinguishing it from other substances in the list that have either depressive effects or do not produce similar stimulatory responses.