Infographic: How beer and coffee affect your brain

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Study: Caffeine, Stress, and Brain function

According to the Food and Drug Administration, caffeine is widely available and upto 80% of adults have caffeine everyday, upto 200mg, which is about 10 ounces of coffee (1).

Sometimes caffeine is used to help stay awake, alert, keep up with academic demands, etc.

While the many benefits of caffeine have been widely documented, problems and side effects caffeine are not as widely known.

One study looked at the impact of caffeine on stress (2).

Who was involved in the study? (2)

  • 25 participants who used caffeine regularly or were light user of caffeine.
  • Subjects received placebo or caffeine (3.5mg per kilogram of body weight, about 238mg for a person weighing 150 pounds)

  • Blood pressure, cortisol (stress hormone), norepinephrine and epinephrine (also involved in stress response and other functions).
  • Measurements were taken at rest, during a stressful laboratory task, and afterwards at rest.

  • Compared to placebo, caffeine caused more than DOUBLE the levels of epinephrine and cortisol, both involved in stress response.
  • Effects were similar in both habitual and light users.
  • Habitual use of caffeine did not development of tolerance to the bodily response.
  • Even at rest, caffeine increased blood pressure and plasma norepinephrine levels.

Caffeine may increase your stress level whether you are using caffeine sporadically or regularly.

What are some other effects of too much caffeine?

  • Caffeine had as early as 7am lead to less efficient sleep and reduced total sleep at 9pm (3).
  • Some people have more daytime sleepiness because of caffeine related sleep disruption (4).
  • Caffeine can reduce bloodflow to the brain by up to 27% (5)
  • Too much caffeine can cause (1):
    • Worsening of anxiety
    • Jitteriness
    • Nervousness
    • Sleep disturbance
    • Headaches
    • Make your heart beat faster, palpitations, high blood pressure, abnormal heart rhythms

  • This is a small study and there are many studies showing positive and negative effects of caffeine.
  • Not everyone has the same benefits or side effects caffeine.
  • The AMOUNT of caffeine that has beneficial and harmful effects can be different for different people.
  • Some people can metabolize caffeine much faster or slower than others (6).
  • For some people, it can take days to weeks to see benefits from reducing or eliminating caffeine.
  • Stopping caffeine abruptly can lead to withdrawal headaches, irritability, and other symptoms.

Are you feeling stressed, irritable or anxious? How is your caffeine intake? Could you benefit from less?

Disclaimer: This article is intended to be informative only. It is advised that you check with your own physician/mental health provider before implementing any changes. With this article, the author is not rendering medical advice, nor diagnosing, prescribing, or treating any condition, or injury, and therefore claims no responsibility to any person or entity for any liability, loss, or injury caused directly or indirectly as a result of the use, application, or interpretation of the material presented.

This Is How Your Brain Becomes Addicted to Caffeine

Within 24 hours of quitting the drug, your withdrawal symptoms begin. Initially, they’re subtle: The first thing you notice is that you feel mentally foggy, and lack alertness. Your muscles are fatigued, even when you haven’t done anything strenuous, and you suspect that you’re more irritable than usual.

Over time, an unmistakable throbbing headache sets in, making it difficult to concentrate on anything. Eventually, as your body protests having the drug taken away, you might even feel dull muscle pains, nausea and other flu-like symptoms.

This isn’t heroin, tobacco or even alcohol withdrawl. We’re talking about quitting caffeine, a substance consumed so widely (the FDA reports that more than 80 percent of American adults drink it daily) and in such mundane settings (say, at an office meeting or in your car) that we often forget it’s a drug—and by far the world’s most popular psychoactive one.

Like many drugs, caffeine is chemically addictive, a fact that scientists established back in 1994. This past May, with the publication of the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), caffeine withdrawal was finally included as a mental disorder for the first time—even though its merits for inclusion are symptoms that regular coffee-drinkers have long known well from the times they’ve gone off it for a day or more.

Why, exactly, is caffeine addictive? The reason stems from the way the drug affects the human brain, producing the alert feeling that caffeine drinkers crave.

Soon after you drink (or eat) something containing caffeine, it’s absorbed through the small intestine and dissolved into the bloodstream. Because the chemical is both water- and fat-soluble (meaning that it can dissolve in water-based solutions—think blood—as well as fat-based substances, such as our cell membranes), it’s able to penetrate the blood-brain barrier and enter the brain.

Structurally, caffeine closely resembles a molecule that’s naturally present in our brain, called adenosine (which is a byproduct of many cellular processes, including cellular respiration)—so much so, in fact, that caffeine can fit neatly into our brain cells’ receptors for adenosine, effectively blocking them off. Normally, the adenosine produced over time locks into these receptors and produces a feeling of tiredness.

Caffeine structurally resembles adenosine enough for it to fit into the brain’s adenosine receptors. Image via Wikimedia Commons

When caffeine molecules are blocking those receptors, they prevent this from occurring, thereby generating a sense of alertness and energy for a few hours. Additionally, some of the brain’s own natural stimulants (such as dopamine) work more effectively when the adenosine receptors are blocked, and all the surplus adenosine floating around in the brain cues the adrenal glands to secrete adrenaline, another stimulant.

For this reason, caffeine isn’t technically a stimulant on its own, says Stephen R. Braun, the author or Buzzed: the Science and Lore of Caffeine and Alcohol, but a stimulant enabler: a substance that lets our natural stimulants run wild. Ingesting caffeine, he writes, is akin to “putting a block of wood under one of the brain’s primary brake pedals.” This block stays in place for anywhere from four to six hours, depending on the person’s age, size and other factors, until the caffeine is eventually metabolized by the body.

In people who take advantage of this process on a daily basis (i.e. coffee/tea, soda or energy drink addicts), the brain’s chemistry and physical characteristics actually change over time as a result. The most notable change is that brain cells grow more adenosine receptors, which is the brain’s attempt to maintain equilibrium in the face of a constant onslaught of caffeine, with its adenosine receptors so regularly plugged (studies indicate that the brain also responds by decreasing the number of receptors for norepinephrine, a stimulant). This explains why regular coffee drinkers build up a tolerance over time—because you have more adenosine receptors, it takes more caffeine to block a significant proportion of them and achieve the desired effect.

This also explains why suddenly giving up caffeine entirely can trigger a range of withdrawal effects. The underlying chemistry is complex and not fully understood, but the principle is that your brain is used to operating in one set of conditions (with an artificially-inflated number of adenosine receptors, and a decreased number of norepinephrine receptors) that depend upon regular ingestion of caffeine. Suddenly, without the drug, the altered brain chemistry causes all sorts of problems, including the dreaded caffeine withdrawal headache.

The good news is that, compared to many drug addictions, the effects are relatively short-term. To kick the thing, you only need to get through about 7-12 days of symptoms without drinking any caffeine. During that period, your brain will naturally decrease the number of adenosine receptors on each cell, responding to the sudden lack of caffeine ingestion. If you can make it that long without a cup of joe or a spot of tea, the levels of adenosine receptors in your brain reset to their baseline levels, and your addiction will be broken.

About Joseph Stromberg

Joseph Stromberg was previously a digital reporter for Smithsonian.

How Alcohol Travels Through the Body

Alcohol requires no digestion and is metabolized before many other nutrients. About 20% of the alcohol you drink passes through the stomach wall and can reach the brain within one minute.The remaining 80% passes through the small intestine before entering the bloodstream.

As Blood Alcohol Concentration (BAC) continues to rise, you begin to lose control of your cognitive functions and motor skills. Before you go drinking on an empty stomach, consider the following infographic from Total DUI which shows how alcohol travels through your body.

[Click image for full size version]

Irma Wallace

Co-founder and Vice President of SearchRank, responsible for many of the day to day operations of the company. She is also founder of The Arizona Builders' Zone, a construction / home improvement portal.

Infographic: How beer and coffee affect your brain - travels



ABOUT 20% of the alcohol you drink passes through the stomach wall and can reach the brain within one minute.

THE REMAINING 80% passes through the small intestine before entering the bloodstream.


Drinking too much alcohol can decrease appetite as a result of increasing gastric juice flow,causing malnutrition.

Drinking too much alcohol stimulates gastric juice flow.

Higher alcohol content can cause stomach lining irritation and lead to ulcers.

On an empty stomach,alcohol passes directly to the blood stream.

Heavy drinkers increase their risk of developing mouth,esophagus,or throat cancer.



temporary feelings of warmth.
temporary decrease in pulse rate.
temporary decrease in blood pressure.


Alcohol can increase urine production as soon as 20 minutes after consumption.

Excessive urination may lead to thirst and dehydration.

Alcohol increases the risk of aspiration-the entrance of foreign material into the lungs.

Once alcohol hits the brain,it immediately starts affecting the brain ability to control behavior and bodily functions.




This is why time is the only thing that can sober up a person.

A fatty liver may develop as alcohol disrupts the livers ability to break down fats.The damage can be reversed by ceasing alcohol consumption.

Healthy liver tissue is replaced by scar tissue,which decreased blood flow to the liver and liver function.


Few obvious effects at this point,Slight intersification of mood.

BAC 06
Emotions are exaggerated,judgement is impaired.

BAC .10
Self control, perception,vision,balance,and speech are affected.

BAC 14-15
Vision,balance,speech,and motor control are affected.Medical evaluation is advised.

BAC .20
Loss of motor control.Requires assistance standing/walking,Medical attention is necessary.

BAC .30
Potential loss of consciousness.Hospitalization is required.

Sleep disturbance.
Decreased attention span.


4-5 ounces of wine.
1.5 ounces of 80 proof distilled liquor.
12 ounces of beer.


One drink per day for women and people over 60.

Two drinks per day for men (no more than one per hour).

Women who are pregnant or trying to become pregnant.

Anyone talking medication,including over-the-counter medicines.

Anyone who plans to drive or participate in activities requiring theri full attention and/or skill.

Anyone under the age of 21.


Reduces stress.
Reduce heart disease risk.
Strengthens bones in post-menopausal women.
Increases appetite.

What Actually Happens When You Combine Alcohol and Caffeine?

Pull up to a bar on any given night and you might hear people order a combination of alcohol and caffeine to keep the fun going, whether that’s in the form of rum and soda, whiskey and coffee, vodka and an energy drink, or some other concoction meant to deliver the perfect double-buzz.

You might remember that whole controversy around Four Loko, the beverage line behind those infamous caffeinated alcoholic drinks that sparked a craze in the early aughts. Everyone was trying to be very drunk, yet also, defiantly, very awake. Soon enough, reports swirled of alarming hospitalizations reportedly linked to the products, especially among underage teens drinking dangerous amounts of the stuff. In 2010, the Food and Drug Administration (FDA) released warnings to Four Loko’s parent company and to companies selling similar offerings, explaining that the agency had never sanctioned the mix of alcohol and caffeine in their beverages. Sales of those products came to a screeching halt. (Four Loko currently states on their website: “Four Loko does not contain caffeine, taurine or guarana. As part of a voluntary product reformulation in 2010, we removed these ingredients.”)

Even so, the alcohol-caffeine combination is still going strong. In fact, one in three young adults surveyed in 2015 had imbibed at least one mixed drink containing alcohol and caffeine in the previous year, according to a National Institute on Drug Abuse survey of 4,000 people between the ages of 19 and 28. Just as enthusiasm surrounding these drinks hasn’t gone away, neither has confusion about the effects that can come with mixing alcohol and caffeine.

Much like what you were thinking when you texted your ex after happy hour, the mechanisms at play here are something of a mystery. Experts do know, however, that a chemical called adenosine has a lot to do with it.

Adenosine builds up in your brain throughout the day, acting on your central nervous system and helping to regulate wakefulness and sleepiness, alcohol researcher Brandon Fritz, Ph.D, a postdoctoral fellow in the psychiatry department at the Indiana University School of Medicine who studies the neurobehavioral effects of alcohol, tells SELF. “When it reaches high levels, it is one factor that makes you sleepy,” he explains.

Caffeine, a central nervous system stimulant, essentially wards off drowsiness by suppressing rising adenosine levels. “Caffeine works to kick-start your [energy] by blocking adenosine receptors in your brain, stopping that sleepy signal and perking you up,” Fritz says. Caffeine also acts on other parts of your body, like your heart. Side effects of caffeine can include a rapid heartbeat, heightened blood pressure, shakiness, dizziness, and anxiety, according to the U.S. National Library of Medicine. The likelihood of experiencing these symptoms depends on various factors, like how sensitive you are to caffeine and how much you have. That’s why the USDA’s Dietary Guidelines set the upper healthy limit for daily caffeine intake at about 400 milligrams a day, or about three to five eight-ounce cups of coffee, depending on the specific drink.

As a central nervous system depressant, alcohol has a wildly different effect on you than caffeine. First, it causes more adenosine to accumulate in your system, Fritz explains, hence why you might doze off after a few drinks, try as you might to stay awake. Drinking alcohol can also slow your reaction times, reduce your balance and fine motor skills, and impair your cognition in a way that causes poor judgment, according to the Centers for Disease Control and Prevention (CDC).

Much like caffeine, alcohol is associated with a temporary increase in heart rate and blood pressure. Does that mean drinking the two together could spell extra trouble for your cardiovascular system? Possibly.

When you consume both alcohol and caffeine, the joint impact on your heart might be what you’d expect from the duo: Your heart rate and blood pressure could increase more when you have them both than when you have just one or the other, depending on the amount you consume. But that doesn’t mean mixing caffeine and alcohol results in doubly strong heart effects than consuming one of them alone.

Susan A. Stoner, Ph.D., a research consultant at the Alcohol and Drug Abuse Institute at the University of Washington, tells SELF there does not appear to be a synergistic effect here, meaning there’s no special, mysterious interaction between alcohol and caffeine that exponentially increases the effects of the other. Basically, the effects of drinking alcohol and caffeine together shouldn’t be greater than the sum of the two combined. But if you’re drinking enough alcohol or caffeine to already experience ill effects on your heart, adding the other can just make it worse.

Ultimately, the research on how this combo affects your heart is somewhat mixed and limited, Fritz says. “The lack of knowledge there thus argues for increased caution,” he says. What’s more, “the long-term effects of the combination on cardiac health [are] not known.”

So, the scientific jury is still out on exactly how dangerous it might be for your heart to mix alcohol and caffeine. But when it comes to your brain, experts say that if you put alcohol and caffeine together, the latter effectively “cancels out” some of the former’s effects. This might sound like a good thing, but it can actually be dangerous.

“A common motive people give for consuming large amounts of caffeine [like] energy drinks along with alcohol is that they are seeking a ‘wide-awake drunk,’ ” Fritz says. Sure, the caffeine can help combat the sleepiness that often comes with a long night of drinking, but it won’t do anything about the way alcohol affects things like your judgment or motor skills.

“The primary effect of the caffeine and alcohol combination is that the sedative effects of alcohol are reduced,” Fritz says. “Your decision-making and coordination will be just as impaired.” Translation: Since you’re drunk, you’ll still be worse at things like making sound choices and driving in a straight line than you would be while sober. You just might not realize it because the caffeine makes you feel all bright-eyed and on top of your game.

It should be noted that all these studies looked specifically at mixing alcohol with energy drinks, as opposed to say, a mixed drink with caffeinated soda or a cup of coffee right before you start drinking. So it’s possible that there are other factors in play here, like energy drink ingredients not present in soda (more on that later). Or maybe people who favor this combination over straight up alcohol or caffeine tend to be more risk-prone people in the first place.

With those caveats in mind, one 2015 review in Drug and Alcohol Dependence analyzing 62 studies found that young adults who drank alcohol with energy drinks experienced more “alcohol-related harm,” like drunk driving and having unprotected sex, than other drinkers.

Watch the video: Your Brain On Coffee

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