Caffeine acts as a central nervous system stimulant. When it reaches your brain, the most noticeable effect is alertness. You’ll feel more awake and less tired.
Caffeine is a common ingredient in medications to treat or manage drowsiness, headaches, and migraines.
Studies have found that people who drink coffee regularly have a lower risk of developing Alzheimer’s and dementia, and cut suicide risk by 45 percent. These benefits are limited to people who drink high-octane coffee, not decaf. Some people consider coffee to be a healthy drink, but like most foods, overindulging can cause side effects.
For example, too much caffeine can give you headaches. This is primarily linked to caffeine withdrawal. The blood vessels in your brain become used to caffeine’s effects so if you suddenly stop consuming caffeine, it can cause a headache.
Other symptoms of caffeine withdrawal include anxiety, irritability, drowsiness. In some people, sudden withdrawal may cause tremors.
Although it’s extremely rare, it’s also possible to overdose on caffeine. Symptoms of an overdose include confusion, hallucinations, vomiting.
An overdose can result in death due to convulsions. Overdosing happens by consuming large amounts of caffeine, most often in energy drinks or diet pills. Up to 400 milligrams of caffeine is considered to be safe. This equals about 4 cups of coffee, although the amount of caffeine in beverages varies widely.