Caffeine is among the most widely used drugs on the planet. It appears in countless foods and beverages ranging from coffee and tea to chocolate, energy bars, and soda. It even appears in some brands of sparkling water.
"Caffeine is a natural stimulant. It makes you more alert and gives you that much-needed boost," says Marjan Moghaddam, D.O., a family medicine specialist at Henry Ford Health. “About an hour after you drink caffeine, your metabolism and heart rate will spike and you'll feel more energized." The trouble is, caffeine can be addictive.
How Caffeine Works
Like any drug, whether a stimulant or depressant, caffeine interferes with the normal communication between your brain and body. Here's how:
- Caffeine acts on the central nervous system. Caffeine acts on neurotransmitters in the brain that slow down the nervous system and cause drowsiness.
- Caffeine dilates blood vessels. Caffeine is a vasodilator, meaning it opens blood vessels in the brain, allowing blood to flow more freely. Headaches result from constricting blood vessels in the brain. "That's one reason why medications designed to fight headaches contain caffeine," Dr. Moghaddam says.
- Caffeine signals the body to produce adrenaline. Caffeine signals the brain to produce adrenaline, the body's mobilization hormone. It also stimulates the pleasure center of the brain, releasing the feel-good hormone, dopamine.
Add it all together and it makes sense that caffeine helps us feel more alert, anxious and even jittery at times.
Can You Build A Caffeine Tolerance?
Caffeine affects people differently. Some folks get anxious and jittery. Others find it helps them focus and enhances their performance. Still others feel like it doesn't affect them at all.
"Caffeine is similar to alcohol in that if you drink it all the time, you can build a tolerance to it," Dr. Moghaddam says. "Many people find they can't get up and moving in the morning without a cup of coffee — and if they skip, they may suffer from debilitating headaches."
So how do you know if you've built up a tolerance to caffeine? The key indicator is if you feel like you need caffeine to function — and if your usual intake, whether from supplements, food or beverages — isn't providing its usual energy boost. Other signs of trouble include things like fatigue, mood swings, headaches and nervous energy when you reduce or eliminate your caffeine intake.
Striking A Healthy Balance With Caffeine
Because caffeine occurs in (or is added to) so many foods, you can overdo it without even realizing it.
While no one is suggesting you need to cut out all caffeinated products, it may be a good idea to talk to your doctor about your unique risk factors as they relate to caffeine use. "The maximum amount people should drink is about four cups of coffee per day," Dr. Moghaddam says.
Quitting caffeine cold turkey usually isn't the best strategy. Not only are you likely to suffer from headaches (depending on the level of your caffeine use), but you'll probably be cranky to boot. A better approach: Vary your caffeine intake each day so your body doesn't expect it at a certain time.
"Some days you can have four cups of coffee. Other days, limit yourself to two," Dr. Moghaddam says. "Then focus on gradually decreasing your overall caffeine intake over time."
As with all things, the sweet spot is moderation. However, if you have a history of high blood pressure or heart arrhythmia, it's probably best to steer clear of caffeine. Since your heart is a muscle, and caffeine is a stimulant, getting too much can increase your heart rate and put strain on your heart muscle.
Your best bet: Talk to your doctor about what level of caffeine intake is best for your unique circumstances.
Marjan Moghaddam, D.O., is a family medicine physician who sees patients at Henry Ford Medical Center in Capitol Park and Harbortown.