a-marathon-runner-reports-that-caffeine-helps-them-feel-less-tired-late-in-races

Question

A marathon runner reports that caffeine helps them feel less tired late in races but also gives them jitteriness and a faster heart rate. Which of the following explains both effects?

Accepted Answer

Caffeine stimulates the central nervous system lowering perceived exertion, while its sympathomimetic action can cause side effects like tremor, palpitations, and anxiety

Answer

Caffeine increases parasympathetic tone producing calmness and reduced heart rate but at the same time causes muscular hypoxia which the athlete interprets as tremor

Answer

Caffeine directly binds muscle oxygen and increases oxygen extraction, which reduces effort perception but causes cardiac oxidative stress manifesting as jitteriness

Answer

Caffeine triggers insulin release which both reduces central fatigue and causes sympathetic overdrive and tremor due to hypoglycemia