Chugging Red Bulls and lattes and taking handfuls of Vivarin, a “stay awake pill,” can be an exam-time ritual for students waiting until the last minute to study, but while ingesting mass quantities of caffeine may help students stay up all night, too much caffeine can cause extra stress on the body.
Caffeine is a central nervous system stimulant that raises alertness and concentration levels by inhibiting adenosine, a chemical in the brain that slows down activity and has a calming effect.
A cup of coffee has about 90 to 150 mg of caffeine, while a Red Bull has 80 mg of caffeine and a Coca-Cola has 34 mg of caffeine. A bar of chocolate has about the same amount of caffeine as a can of Coca Cola, but the recommended dose of Vivarin has 200 mg of caffeine.
While consuming caffeine can keep students from getting drowsy studying for a final, Sarah Ash, associate professor in food, bioprocessing and nutrition sciences, said caffeine also increases heart rate, alertness and wakefulness, but evidence is mixed on whether caffeine actually improves learning.
“You might be better off taking a power nap and returning to your studying afterwards rather than pushing your way through the exhaustion with caffeine,” Ash suggested.
According to Lisa Eberhart, University Dining dietician, caffeine can stay in your system for up to six hours, so it is possible that drinking a caffeinated beverage in the afternoon can cause restlessness at night, even during sleep. Waking up and taking an exam may be more difficult if a student is sleep-deprived.
Irritability, restlessness, anxiety and heart palpitations are also possible side effects of caffeine, Eberhart said, but, for most people, the amount of caffeine in two to four cups of coffee is not harmful.
“Caffeine sensitivity, the amount of caffeine that will produce an effect in someone, varies from person to person,” Eberthart said. “A small amount of caffeine may effect you while another person can consume more caffeine with few side effects.”
Caffeine’s effects also depend on a person’s size and his or her prior use of caffeine, Ash said. “People can develop a tolerance to it, requiring more to get the same effect,” she said.
Students may also experience withdrawal symptoms without caffeine, most notably a headache, if their bodies are accustomed to ingesting a certain amount daily, Ash said.
Because caffeine is a diuretic — it causes a person to urinate more frequently — Eberhart said, and some people believe this may cause dehydration.
“To be safe,it’s probably a good idea to stay away from too much caffeine in hot weather, during long workouts or in other situations where you might sweat a lot,” Eberhart said.
But some studies have shown that caffeine consumption boosts concentration, Eberhart said.
”So if you need to really focus,” she said, “a little caffeine may help.”
