Caffeine is a stimulant that blocks certain chemicals in the brain, preventing signals of sleepiness and languor from being transmitted. Caffeine can also improve reaction times, memory and reasoning skills. However, in high doses, caffeine can make people anxious or irritable and make it difficult to fall asleep at night.Continue Reading
Caffeine imitates adenosine, a neurochemical that creates feelings of fatigue and tiredness. Caffeine enters the adenosine receptors without actually activating them, preventing those feelings from taking hold and allowing dopamine and serotonin to stimulate the brain freely. Caffeine's temporary energy boosts are associated with increased heart rate, stomach ache and headache.
Caffeine is addictive and can cause withdrawal symptoms of headaches, drowsiness and irritability. Over time, most people develop a tolerance to caffeine and require more to block a similar amount of adenosine. The amount that a person can drink depends on her height, weight, age and metabolism. Withdrawal symptoms can last up to 10 days.
The initial symptoms of caffeine intoxication include restlessness, cramping, nervousness and insomnia. After 1,000 milligrams of caffeine, symptoms may include muscle twitches, rapid heartbeat and psychomotor agitation, among others.
While coffee and tea are the most well-known sources of caffeine, the chemical is commonly found in chocolate, soda and medication. Even coffee-flavored ice creams or snacks contain variable amounts of caffeine.Learn more about Beverages
Energy drinks work primarily by distributing a large amount of caffeine to the central nervous system which gives the drinker a greater feeling of alertness. Taurine increases oxygen flow to the cells, lessens muscle contractions and regulates heartbeat and energy levels. Guarana provides additional caffeine and increases alertness and energy levels.Full Answer >
Hot chocolate can contain anywhere from 9 milligrams to 24 milligrams of caffeine. The caffeine content depends on several factors, such as the percent cacao of the product, where the cocoa beans were grown, how the beans were processed after harvest and the quantity of one serving size.Full Answer >
Red Bull energy drink contains caffeine, and users can experience side effects related to their level of caffeine intake. Some side effects associated with consuming energy drinks such as Red Bull include elevated heart rate, anxiety and upset stomach. Other common side effects associated with ingesting large amounts of caffeine include headache, agitation, nausea, vomiting and chest pain. Drinking Red Bull might worsen existing conditions such as sleep disorders and diarrhea.Full Answer >
Like most regular Snapple flavors, Diet Snapple contains moderate levels of caffeine. The amount of caffeine per drink varies based on the selected flavor, but most flavors contain 42 milligrams of caffeine per 16-ounce bottle.Full Answer >