Caffeine: Here's What the Experts Really Want You to Know |National Geographic |National Geographic

Caffeine: Here's what the experts really want you to know

Caffeine does have health benefits, but only if you don't overuse it.Here are the effects of coffee, energy drinks and other caffeinated products on your health.

The most widely used drug in the United States is caffeine, which comes in familiar forms such as coffee cups as well as fancy forms such as inhalation powders.But what does this stimulant do when it enters the body?

Caffeine is by far the most popular drug in the United States.A 2025 survey published in the journal Food and Toxicology found that about 70% of Americans consume at least one caffeinated beverage per day.

But caffeine is no longer limited to the cup of coffee.It is available in the form of gels, powders, gums or even sachets to place under the tongue;There's even caffeinated beef.Never before has there been so much variety in administration methods and flavors available to caffeine drinkers.

The Food and Drug Administration (FDA) recommends consuming no more than 400 mg of caffeine per day.A 24 cl cup of filter coffee typically contains around 95 mg of caffeine, while many popular energy drinks contain 100 to 200 mg per serving.35 cl.In individual servings, these doses pose no danger to most people, but problems often begin when people start consuming too much.

Although caffeine has many health benefits, it can quickly cause side effects when consumed in large doses.Here's what you need to know about the pros and cons of this pleasure substance and who should be extra careful when using it.

What happens in the body when you consume caffeine?

Caffeine is a compound found naturally in coffee, tea and mate and is an active ingredient in thousands of pre-workout supplements and energy drinks.

When caffeine is consumed, it blocks the uptake of adenosine in the brain.This substance accumulates during awakening and plays several roles in the body.When adenosine binds to its receptors, it promotes sleep and helps regulate circadian rhythms.During sleep, the brain releases adenosine, which makes you feel relaxed and alert when you wake up.But caffeine, alcohol and certain sleeping habits can disrupt this process.

Caffeine blocks adenosine receptors and prevents them from binding to them and sending the "bat signal" that indicates it's time to sleep.Blocking adenosine receptors promotes the release of other neurotransmitters, including dopamine, adrenaline, and epinephrine.

"That's why we see the effects of caffeine on mood, energy, attention and concentration," explains Robert Cowan, a Stanford University neurologist and director of headache research.

How long caffeine stays in the body and how long it prevents you from sleeping well varies from person to person.The general recommendation stated by Robert Cowan is not to exceed 400 mg per day and stop using it after 2pm.

Although the stimulating effects of caffeine can be highly beneficial, "the brain is not easily fooled," warns Robert Cowan.After regular use, it will soon think that caffeine is part of the body's normal functioning.Therefore, when a regular caffeine user suddenly stops taking it, the brain thinks there is a problem and sends a signal in the form of a headache, irritability or fatigue.

HOW CAFFEINE HELPS THE BODY

Caffeine has a number of health benefits depending on how you use it.For example, energy drinks do not contain the added compounds found in tea and coffee, such as polyphenols and antioxidants, which are beneficial to your health.

"When we talk about the health benefits [of caffeine], we're really talking about coffee [and tea]," says Michael Frederickson, a sports physician and professor at Stanford University.

Surprisingly, a study conducted in England showed that ground and instant coffee (but not decaffeinated) was associated with a reduction in arrhythmias, that is, irregular heartbeats.

in sport and performance Not all caffeine is created equal

Bryan Saunders, a researcher at the Doctor of Medicine at the University of São Paulo said "I don't think there is a supplement like caffeine to improve physical performance," In his research, Bryan Saunders found that just thinking about receiving caffeine intake, before receiving a placebo, improves performance almost as much as caffeine itself.

Caffeine can improve concentration while reducing feelings of pain and tension, making it an ideal compound for performance."You can work harder without feeling like you're working as hard," says Brian Saunders.And this is something that is especially useful for endurance athletes.

The World Anti-Doping Agency (WADA) also attested to the power of caffeine: the organization added this compound to its list of prohibited substances until 2004, although an athlete had to consume several cups of coffee in a row to exceed the threshold of 12 µg/ml in urine.

Regarding physical activity, the general recommendation of the International Association of Sports Nutrition is, without exception, three to six milligrams of caffeine per kilogram of body weight.For example, for an 80 kg person, this represents 250 to 490 mg of caffeine, which is slightly more than the FDA's daily recommendation.

According to Michael Fredrickson, caffeine can also improve reaction time and attention to detail, but it can also cause negative side effects: tachycardia, nervousness, anxiety, and sleep problems.

Michael Frederickson warns that "there is a fine line" between benefits and side effects.

IF YOU ARE AWARE OF CAFFEINE

Certain groups of people need to be especially careful with their caffeine intake.

The American College of Obstetricians and Gynecologists recommends that pregnant women limit caffeine intake to 200 mg per day.Larger amounts may increase the risk of miscarriage and birth defects.

People with heart disease should also be extra careful with their caffeine intake, says Robert Cowan, who also has kidney or liver problems.

Anxiety, tremors, difficulty sleeping, confusion and disorientation in thinking can be signs of excessive caffeine consumption. Irregular consumption can also cause headaches, especially in migraine sufferers and those who are more sensitive to caffeine. Meanwhile, low-dose caffeine users who experience headaches can sometimes relieve them by drinking a cup of coffee or even a Diet Coke. The small amounts of caffeine contained in these drinksthey help constrict blood vessels and increase the effectiveness of medications.

"It's kind of the old argument 'Too much water and you will drown,'" says Robert Cowan about the benefits and harms of caffeine.

Caffeine can increase the absorption of other drugs, which is why it is sometimes found in prescription drugs or even sold without a prescription (eg Excedryn).According to Robert Cowan, it is also worth being careful with the caffeine intake of people taking heart medication, as it can affect the amount absorbed into the blood.

Michael Frederickson does not recommend energy drinks for youngsters, as does the American Academy of Pediatrics (AAP).But 30 to 50% of them are still drinking, according to the US Centers for Disease Control and Prevention (CDC).

Caffeine, in general, interrupts the brain the plane is most likely to be much of the temporary."

"This is the last thing you need in your life right now," warns Michael Frederickson.These kids are already under too much stress, so that's my main concern."

Caffeine, taken in the wrong doses or at the wrong time, can disrupt sleep in adults and cause many health problems, which can be prevented by consuming caffeine in moderation.According to Michael Frederickson, sleep disorders can increase your risk of cardiovascular disease, diabetes, and Alzheimer's disease.

Robert Cowan's advice is to exercise moderately and regularly with caffeine.In addition to daily caffeine limits, the FDA recommends stopping consumption afterPeople with slower metabolisms of caffeine should stop earlier in the day so as not to disturb sleep, while those with fast metabolisms can sometimes drink an espresso after dinner without worry.

Everyone is different, but Michael Frederickson recommends two to four cups a day.

"You have to find what works for your body."

This article originally appeared on the nationalgeographic.com website in English.