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Coffee Tips

How Does Coffee Work?

With over 1 billion people drinking coffee daily worldwide, it’s no surprise that coffee ranks among the top preferred drinks. At least 1.4 billion cups of coffee are consumed worldwide daily. That’s a lot of coffee. But despite this widespread consumption, only a few people understand how coffee works in the body.

Whether you take coffee as a habit, for its rich flavor and taste, or wholly rely on it for stimulatory and mood-enhancing effects, it’s essential to know how it affects your brain and body so you can wholly embrace its magical powers.

caffeine added to coffee

This article takes you through how coffee works, what it does in your body from when you ingest it.


For centuries, coffee has been a staple beverage in homes around the world. If not at home, coffee shops make it easy to access the favorite Cup of Joe in just about any neighborhood. There’s no question about people’s love for coffee. From rich espresso, pure black, to creamy lattes, coffee has proven to be more versatile than most beverages. The range of flavors and styles suit a range of coffee lovers’ tastes. The biggest perk in every sip of coffee is caffeine, which is also the most substantial component of coffee.

What is Caffeine

Caffeine is the most widely consumed psychoactive substance. It is a natural stimulant that occurs in coffee, tea, and cacao plants. It is responsible for the stimulation effects on the brain and the central nervous system, which causes alertness. For most people, the good thing about caffeine is that its effects are felt almost instantly. On consuming coffee, people report experiencing a waking-up effect. It’s no wonder each day, billions of people rely on the stimulant to wake up, boost their energy, and get through their morning.

How Much Caffeine is in Coffee?

Coffee is a dietary source of caffeine. An average cup of coffee (8-oz) contains about 95 mg of caffeine; however, this amount varies across different coffee drinks and can sometimes range from as little as close to zero to as much as 500 mg. The preparation method also matters; for instance, a slower process used to prepare cold brews extracts more caffeine than other faster processing methods.

How Caffeine Works

Once ingested, caffeine is quickly absorbed into the bloodstream from the gut. In the blood, it travels to the liver where it’s broken down into compounds that can affect the body organs.

How Caffeine Works in the Brain

Even though caffeine affects the body organs, the compounds mainly affect the brain. In the brain, caffeine mainly affects the functionality of adenosine, the nervous system depressant. In science terms, adenosine’s main functionality in the brain is to bind adenosine receptors, a process that causes the nerves to slow down cell activity causing drowsiness. The slowing down of nerve cell activity also causes the blood vessels to dilate, which lets in more oxygen into the organ.

To the nerve cells, caffeine looks like adenosine; hence it acts as an adenosine receptor. It functions by blocking the effects of adenosine, which is the neurotransmitter that relaxes the brain and makes you feel tired and sleepy. Instead, caffeine takes the place of the receptors that adenosine would normally bind to. So, instead of the slowed-down nerve activity, they speed up. This causes constriction of blood vessels.

The pituitary gland interprets the increased neuron firing caused by caffeine to mean that there’s an emergency that must be occurring. As a result, it releases hormones that signal the adrenal glands to rapidly increase adrenaline (epinephrine) levels. Adrenaline, also known as the fight or flight hormone, affects the body in various ways:

  • Pupils begin to dilate
  • Airway opens up
  • Blood vessels constrict to increase flow to the muscles
  • Blood pressure rises which affect the heart rate
  • The flow of blood to other areas such as the stomach slows
  • The liver instantly increases sugar into the bloodstream to increase energy
  • The muscles tighten up and are ready for action

This is what’s usually happening when you drink coffee. Besides, it happens very quickly as it can take as few as 10 minutes from the time you drink your coffee to start experiencing these effects. It also explains why you’ll begin to feel tense muscles, excitement, cold hands, and a faster heartbeat after taking a cup (or three) of coffee. In about 45 minutes after taking your favorite beverage, about 99% of caffeine is already absorbed in the body, with peak blood concentrations happening as soon as 15 minutes after consumption.

Apart from adenosine, caffeine also affects other neurotransmitters; dopamine is one of them. Dopamine is the neurotransmitter that stimulates pleasure (the feel-good chemical) in the brain. Caffeine has similar (though milder) effects as those of heroin and cocaine. Studies suspect dopamine to cause caffeine addiction or dependency, which causes withdrawal symptoms such as headaches and grumpiness when waking up.

You’re likely to experience the effects of caffeine (mostly) in the short term, especially if you’re trying to remain active. Here’s why; caffeine by blocking adenosine helps you feel alert. It further increases the reabsorption of adrenaline, which gives you a big burst of energy and attentiveness and makes you feel good.

However, this vicious cycle can be problematic in the long term.

A cup of coffee helps you induce adrenaline, which wears off and you face fatigue and depression. Another dose of coffee will get the adrenaline flowing again, but if repeated for so long will have the body running in a state of emergency, which isn’t healthy or sustainable.

The most critical and long-term problem that may result from this cycle is sleep deprivation. Coffee has a half-life of about six hours. This means that drinking a cup of coffee that contains 200 mg of caffeine at 4:00 pm. will leave about 100 mg of caffeine in the system by 10:00 p.m. Even this seemingly little caffeine in the body affects adenosine, which is important for sleep—especially deep sleep.

Even if you may be able to sleep after consuming your cup of coffee, your body will miss out on the benefits of deep sleep. Remember that the average half-life of coffee—how quickly your body metabolizes caffeine—really depends on your genetics and body chemistry. As such, the average half-life may be shorter or longer, which will affect your sleep accordingly.

While this may not seem harmful in a day, sleep deficits add up fast and can worsen. To some extent, the cycle will inevitably stop where coffee will fail to give the same effects as before, forcing you to increase your dose. Trying to quit will leave you fighting headaches, tired, or depressed.

Furthermore, caffeine affects the nervous system negatively with its record of increasing stress, anxiety, panic attacks, and proper functioning of the body. High doses, for instance, can mess with the chemical composition of the brain resulting in jitteriness and nervousness. Besides, if you’re already struggling with any mental health or heart challenges, be careful to take it in moderation or as advised by your doctor as it can cause adverse effects. The daily recommended safe dose of caffeine is 400 mg (about 4-8-oz cups of brewed coffee) for a healthy adult.

Health Benefits of Coffee on the Body

Although further research is required to prove these benefits, coffee, if consumed in moderation, can benefit your body in numerous ways:

  • The drink contains substantial antioxidants that help rid natural waste that cause inflammation and other issues in your body.
  • Coffee improves energy levels and various brain functions such as memory, vigilance, and general mental function.
  • Increased energy levels improve physical performance by preparing the body for intense physical exertion.
  • While coffee lacks dietary value, it aids in burning body fat. It also contains no calories, making it a preferred substance for those looking to lose weight and those suffering from weight conditions such as obesity.
  • The drink contains essential nutrients (though in small amounts) such as pantothenic acid, riboflavin, manganese and potassium, magnesium, and niacin.
  • Regular coffee drinkers are less likely to develop Parkinson’s disease, Alzheimer’s disease, heart failure, liver and colorectal cancer, type 2 diabetes, gallstones, and cirrhosis.
  • Besides, caffeine is beneficial in boosting moods which decreases depression and suicidal thoughts, treating asthma and headaches.

Knowing how coffee works and how this affects your brain and your body is an important step towards being an informed coffee drinker. Coffee, as a highly preferred drink among many, is meant to be enjoyed. And thanks to its oxidants and other functional design components, coffee offers the body numerous benefits. But for the benefits to be fully realized in your body, you must enjoy your favorite Cup of Joe responsibly.