Every person makes a chemical called adenosine throughout the day. As it builds up in your body, it makes you sleepy. The caffeine molecule displaces the adenosine, which is why you’ll feel more awake after consuming caffeine.
It goes to your heart muscles and triggers the release of chemicals that help with muscle contraction. If you aren’t a regular caffeine drinker, it can raise your blood pressure. This effect goes away with daily users. Overall, small to moderate doses may decrease your chances of a heart attack or stroke— by association.
A Hershey’s chocolate bar has 9 milligrams of caffeine. Iced tea has 15 to 20 milligrams. A standard diet Coke or Pepsi and an espresso shot has about 40 milligrams. An 8 ounce can of certain energy drinks have standardly 80 milligrams of caffeine. A standard 8 ounce cup of coffee has about 100 to 200 milligrams of caffeine.
It’s used to treat headaches— not ones caused from caffeine withdrawal. They help with tension headaches and migraines. When you add caffeine with aspirin or Tylenol, it’s more effective than just the medicines alone.
Based off of expert opinions of association, most say that consuming more than 200 milligrams or less of caffeine per day is safe. That’s about 1 cup of coffee, depending on size. It would be difficult to conduct a study on pregnant women.