What Exactly Does Caffeine Do to Your Body?

John Schnobrich

There are some things in life we don’t question because we don’t want to know the answer. The mechanisms of how caffeine works may fall into this bucket. After all, we love our caffeine and even need it on a daily basis. So, if you’ve ever wondered what exactly goes on in the body when you drink a caffeinated beverage, and what are the short and long-term effects can be, read on.

Caffeine is a drug

Caffeine is classified as a stimulant, which speeds up messages between the brain and the body. It is considered the most widely used psychoactive substance in the world, but it’s also a naturally occurring substance that is safe for general public consumption.

However, caffeine can also be synthetically produced, which is what is found in a lot of commercial beverages like energy drinks and soda. This is what can make it so tricky to keep track of when it comes to your personal caffeine consumption, and how that may lead to long-term side effects.

When you drink caffeine

There are a few physiological processes that are happening when you consume caffeine, says Stephanie Schiff, a registered dietitian nutritionist and certified diabetes care and education specialist for Northwell Health. First, caffeine stimulates dopamine and slows down the rate dopamine is absorbed into the body by blocking adenosine receptors.

“Dopamine helps with learning and pleasure motivation,” says Schiff. “If your dopamine levels are low, you can feel unmotivated and moody.” Dopamine is known as the happy hormone, which is why when you first drink something caffeinated, you tend to feel like a million bucks.

Adenosine receptors (which are located primarily in the brain) are also responsible for regulating and inducing sleep, says Schiff. When you drink caffeine, you feel more awake and alert. The flip side to this is that when you have something with caffeine in it too late in the day, you may find it more difficult to fall asleep that night.

Too much caffeine can lead to health concerns

If we all consumed natural sources of caffeine, such as in coffee or tea, our caffeine consumption would likely be much less. However, it’s this addition of synthetic caffeine sources that can often lead to over-caffeinating. The setbacks, however, are far worse than having too much energy.

To start, research has found that consuming 400 mg of caffeine anywhere within six hours of bedtime may disrupt sleep. However, even with a buffer of six hours or more, this amount of caffeine may result in one hour less of sleep overall. “If this happens too often, it may affect your ability to function when you’re awake, you may rack up a sleep deficit, and it may impact how deep you sleep,” says Schiff.

Too much caffeine – which, per the Food and Drug Administration (FDA), would equate to more than 400 mg daily can lead to a host of problems ranging from mild to serious. This can include things such as:

  • Headaches

  • Anxiety

  • Increased heart rate

  • Chronic insomnia

  • An increase in blood pressure

  • Excess stomach acid, which can contribute to gastrointestinal conditions like heartburn and GERD

What makes caffeine so tricky, says Schiff, is that it affects everyone differently. This means it’s important to take note of what you feel like when you consume different amounts of caffeine and adjust accordingly for your health and overall comfort.

Caffeine has benefits too

Before you toss your coffee maker, rest assured that drinking low to moderate amounts of caffeine can help your health.

“Coffee and tea are high in antioxidants, which can reduce inflammation in the body and help prevent various diseases,” says Schiff. “This can lead to a longer life, since coffee drinkers may be less likely to have heart disease, kidney disease, a stroke, and/or diabetes.”

Schiff adds that low to moderate caffeine intake (between 50 mg and 300 mg) can make you more alert, improve concentration, and has been found to increase endurance, speed, and muscular strength when consumed 60 minutes before exercising.

As with most things in life, it’s important to remember everything in moderation. Keep your caffeine intake balanced to reap its benefits and make more healthy choices as you go about your day.