How Caffeine Affects the Body: Myths vs Facts

The facts are in: The world is obsessed with caffeine. Whether gulping down coffee, nursing an energy drink or capping off the evening with espresso martinis, 90 percent of American adults consume the plant-based stimulant daily.^[1]

A lot of the buzz has to do with benefits—energy, focus and concentration, just to name a few.^[2] But the caffeine craze has also turned controversial with myths swirling that regular consumption of the stimulant negatively affects the body. This includes theories that caffeine stunts growth and causes heart disease.

So, is caffeine bad for you? Here, we sift through myths vs facts and answer how caffeine really affects the body.

What Does Caffeine Actually Do to Your Body?

You already know how caffeine makes you feel—more awake, focused and ready to conquer the day. But what’s really happening below the surface?

Here’s a closer look.

Caffeine and Energy Levels

Fatigue is no match for caffeine. As a stimulant, it’s responsible for increasing activity in the brain and central nervous system.

Caffeine blocks adenosine receptors (adenosine is a neurotransmitter that promotes sleepiness) to kick energy into motion.^[3] It also supports feel-good neurotransmitters, such as dopamine and serotonin, for a long-lasting mood boost.

Caffeine and Sleep

If you consume too much caffeine (or too late in the day), the journey from sip to sleep may be exhausting. You may take longer to fall asleep, clock in fewer hours and toss and turn.^[4]

If that’s not bad enough, you’re more likely to go overboard on caffeine the next day to compensate for a crappy night’s sleep. This reinforces the vicious caffeine cycle.

What Are the Side Effects of Caffeine in the Body?

When it comes to caffeine, too much of a good thing applies. The Food and Drug Administration found that 400 mg (about three to four 12-fluid-ounce cups of coffee) is a safe daily caffeine consumption for most adults.^[5]

Your perfect cup varies depending on different factors, such as sensitivity to caffeine, medications you’re taking and whether you’re pregnant or breastfeeding.

If slam-dunking caffeine has become a sport, you’re more likely to experience unpleasant symptoms, such as caffeine jitters and the dreaded coffee poops.

Additional caffeine side effects include:

• Headache
• Nausea
• Nervousness
• Fast heartbeat
• Heart palpitations
• High blood pressure
• Insomnia

Long Term Effects of Caffeine Use

If your relationship with caffeine started young and shows no signs of stopping, you’re not alone. Caffeine is the most popular psychoactive substance worldwide.^[6]

But being a coffee aficionado can have a dark side. One potential long-term effect is insomnia, a sleep disorder where it’s hard to fall asleep and stay asleep. This is largely affected by your daily intake of caffeine and timing.

After drinking coffee, the body absorbs 99 percent of caffeine within 45 minutes.^[7] The life cycle of caffeine in the body ranges between two hours and 12 hours. The number varies from person to person depending on metabolism, genetics and lifestyle choices (such as smoking).

To avoid burning the midnight oil, finish your last serving of caffeine earlier in the day. Putting the coffee down at 12 p.m., for example, should be enough time for the caffeine to leave your system.

Additionally, you can avoid counting sleep by counting your daily intake. In studies, insomnia was reported in heavy caffeine consumers (those who consume 600 mg or more per day)^[8] so, keep your intake below the daily 400 mg whenever possible.

Is Cutting Out Caffeine Good for You?

Cutting out caffeine is a double-edged sword aka there are negatives and positives.

Here, we explore the pros and cons to help you make the best decision.

How Do I Know If Caffeine Is Affecting Me?

If the problems of caffeine outweigh the perks, you may be sensitive to caffeine. You may experience symptoms after consuming only a small amount of caffeine.

Side effects include:

• Jitters
• Anxiety
• Heart palpitations
• Headaches
• Diarrhea
• Frequent urination
• Insomnia

Genetics can play a role, specifically the CYP142 enzyme, which may impact how fast the body metabolizes caffeine.^[9]

Caffeine sensitivity is not to be confused with caffeine intolerance or allergy. These are much more serious conditions that could cause these symptoms:

• Itchy skin
• Hives
• Facial swelling (lips, throat and tongue)
• In rare cases, difficulty breathing or anaphylaxis (a life-threatening condition)

Should You Quit Caffeine?

Calling curtains on caffeine isn’t an easy decision. Many have tried and many have failed.

If you’re sensitive to caffeine, your health is a good enough reason to cut back or call it quits. But if you down espresso with ease, a closer look at your relationship with caffeine may be needed to determine if it’s one worth keeping.

Consider keeping a running log so you can track any unpleasant symptoms after consuming caffeine. Headaches? Irritability? Anxiety?

Also, do a coffee audit to determine your dependency on caffeine. How many cups are you drinking per day? Are you sleeping well? Tracking your experience over time will help you decide where you and caffeine stand.

How to Transition Off Caffeine Safely

Going cold turkey on caffeine sounds great in theory. But in reality, withdrawal symptoms can happen within 12 and 24 hours as the brain adjusts to life without its dear friend.^[10] Potential awful symptoms include headaches, irritability and fatigue.

The key is to transition off caffeine gradually. Here are some tips to combat yourself and make the process less of a headache.

• Wean off caffeine slowly. Give yourself a window of three to four weeks. If you are drinking four cups of coffee per day, drink three cups per day for a week. Eventually reduce it to two and continue tapering off slowly until your caffeine habit has been safely kicked.
• Make small changes. Make doable swaps to build momentum and make the process easier. For example, switch from caffeine-heavy espresso to light roast coffee and caffeine-sodas to flavored sparkling water. Ditch black tea for little-caffeine to caffeine-free varieties, such as green tea or sage. How much caffeine is sage tea? It’s caffeine-free, so rest assured that you’ll get a good night’s sleep.
• Hydrate. Drink lots of water to energize your body in much the same ways caffeine does.
• Take a pain killer. Headaches are one of the most common symptoms of caffeine withdrawal. Stay ahead of the pain by taking over-the-counter pain killers.
• Get enough sleep. Fatigue is one of the common symptoms of quitting caffeine, so aim to get seven to nine hours per night

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Caffeine Myths vs Facts: Common Misconceptions

There has been a lot of tea about caffeine—and not the good kind. These rumors run the gamut of caffeine dehydrating you, stunting your growth and raising your risk of an early grave.

Here, we debunk what’s real and what’s fiction.

Myth one: Caffeine stunts growth

Much like the Boogeyman under the bed, caffeine affecting growth is a white lie told by parents to prevent kids from unwanted behavior. It reportedly originated from an advertising campaign in 1895.

Those who sipped coffee young will be glad to know that caffeine affecting growth is not scientifically accurate.^[11] In fact, it may be linked to another myth about caffeine causing osteoporosis.

Myth two: Caffeine causes osteoporosis

Osteoporosis is a bone disease that causes weak, thin bones. This can result in an increased risk of bone fractures. Decades ago, researchers believed that caffeine causes the body to lose more calcium through urination. Since calcium is an essential mineral for good bone health, they linked caffeine to causing osteoporosis.

But when these findings were analyzed with fresh eyes, it was found that the participants in the studies consumed lots of caffeine and not enough calcium-containing beverages, such as milk.^[12] As a result, the osteoporosis in participants was likely caused by a lack of dietary needs, not caffeine intake.

Myth three: Decaf coffee has no caffeine

Switching to decaf in the hopes that you’ll avoid caffeine? You may be surprised to learn that decaf still contains caffeine. The decaffeination process removes about 97% of caffeine, leaving behind about two mg per cup.^[13]

While not completely caffeine-free, it’s still significantly less caffeine than the average cup of Joe (about 95 mg for an eight-ounce cup).^[14]

Myth four: Caffeine raises your risk for heart disease

If you’re sensitive to caffeine, elevated blood pressure is par for the course. Older research even blamed caffeine for increasing the risk of heart disease from long-term high blood pressure.

But a fresh look from newer studies didn’t find a link between heavy caffeine drinkers and the risk of coronary artery disease and stroke.^[15] So while caffeine increases blood pressure, the long-term effects aren’t substantial enough to avoid the brew.