Your Body on Caffeine


Let’s face it: you’re probably addicted to caffeine. What began as one cup in the morning to help you get your day started soon turned into your need for three, then four, then five mugs for you to even get out of bed. But let’s back up a minute: how did this happen? The answer is simple—your body became dependent on caffeine without you ever knowing.

Brief History on Coffee in North America

Coffee was first brought to the New World by the British in the mid-1700s, but didn’t take off until the late-1700s where the Boston Tea Party caused a mass switch from tea to coffee among the colonists. By the 18th century, coffee became of the world’s most in-demand goods which still remains true to this day. Fast forward a couple centuries, 80-90% of the population in North America today consumes some form of caffeine daily.[1]

What is Caffeine?

One of the main chemical components in coffee is caffeine, with one cup containing about 95 mg. By definition, caffeine is type of stimulant: an overarching term that describes substances that increase the activity of the central nervous system (CNS) which includes the brain and spinal cord.[2] There are many desirable effects of caffeine’s stimulant-like properties, such as increased awareness, enhanced concentration, and improved cognitive function.[3] Most notable and sought-after, coffee helps its drinkers feel more awake and alert, regardless of how little sleep they may have gotten the night before. Thus, it’s typically popular among college students and working adults.

Recent Studies on Caffeine

A recent study from UC Davis that studied the relationship between caffeine in coffee and work performance found that when coffee is served during business meetings, drinking a moderate amount can enhance your performance working in teams and boost your perception of others in a group setting.[4] A second study also found that when coffee is consumed in higher amounts, it may be linked to a lower rates of Parkinson’s disease (a progressive and often fatal neurodegenerative disease that affects movement) and some forms of dementia.

It has also been found coffee drinkers may experiences a lower chance of having conditions such as cardiovascular disease, type two diabetes, and cancers of the colon, uterus, and liver.[5] It is believed that coffee has these protective effects due to the combination of caffeine and antioxidants found within its beans.

How Does Caffeine Work?

Coffee is able to help people feel more awake during the day because caffeine’s molecular structure is very similar to that of adenosine: a neurochemical that makes us sleepy. The caffeine molecules bind to adenosine receptors in the brain, effectively blocking the chemical from binding with the receptor and making us feel tired.[6] Essentially, it’s like a lock and key where adenosine receptors are the lock that can be opened by both adenosine and caffeine keys.

Lesson Plan: Am I More Awake? Or Just Not So Sleepy? The Effects of Caffeine (and Adenosine) on the Body

However, there is a catch: the brain has a unique ability to build new adenosine receptors in response to so many of them being blocked off by caffeine. The brain uses adenosine receptors to tell you when you should sleep, which in turn helps keep its cells, tissues, and functions healthy. So if you keep blocking them off with caffeine, the brain has no choice but to build new receptors that outnumber the ones being blocked off. This means that overtime, caffeine consumers will have to drink more and more caffeine if they want to experience the same buzz they had when they first started.

Negative Effects of Caffeine

Besides the addictive factor of caffeine, there are many negative effects that it can have on the body if consumed at levels higher than the recommended amount. Generally speaking, it is advised that the total daily intake of caffeine should not exceed 400 mg. If this is exceeded, you may experience irregular heart beats, seizures, hallucinations, chest pain, uncontrollable muscle movements, and even hormonal imbalances if continued long-term.[7] In fact, a study from 2018 found that there were nearly 100 caffeine-related deaths that year, putting into perspective just how careful you should be when drinking highly-caffeinated beverages like energy drinks.[8]

Caffeine Withdrawal

Quitting caffeine isn’t as easy as you might think. In fact, those who have become addicted and attempt to quit experience caffeine withdrawal, which is actually recognized as a diagnosable disorder. Symptoms of caffeine withdrawal can be quite severe, with some experiencing headaches, fatigue, depression, irritability, nausea, vomiting, and muscle pain. The onset of symptoms typically begins 12-24 hours after the last consumption of caffeine, peaks within 1-2 days, and can last over a week.[9]

However, escaping caffeine withdrawal syndrome is entirely possible. It is recommended that if you are looking to quit, you should gradually reduce your caffeine consumption by substituting your daily coffee or tea for decaffeinated or non-caffeinated versions instead of cutting caffeine overnight.

Health Benefits of Quitting Caffeine

There are many health benefits to quitting or at least reducing your caffeine intake. For example, you might experience less anxiety, have an easier time falling asleep at night, maintain greater bone health, calm gastrointestinal issues, and even reduce your risk of tooth decay.[10] So if you are looking to reap some of these benefits, tackle the root of your caffeine addiction. If you are tired and need coffee to wake you up, make sure you are getting the recommended 7-9 hours of sleep each night. Or if you simply like the taste of coffee or tea, always go with a decaffeinated option. And if your looking for more resources to learn about the science of addiction in greater depth, check out these free resources:


[1] Karima, R. et al. (2020). Caffeine Withdrawl. National Center for Biotechnology Information (NCBI). Retrieved from:

[2] Meaning of stimulant in English. Oxford Dictionary. Retrieved from:

[3] Coffee and the Mind. The Institute for Scientific Information on Coffee. Retrieved from:,on%20alertness%2C%20attention%20and%20concentration.

[4] Akin, T., & Hooker, B. (2018). Coffee with Coworkers Is More Productive and Feels Better, UC Davis Study Finds. UC Davis Graduate School of Management. Retrieved from:,have%20been%20dedicated%20to%20coffee.

[5] How Coffee Effects the Brain, Body, and Health. (2020). Neuroscience News. Retrieved from:,caffeine%20and%20antioxidants%20in%20coffee.

[6] Stromberg, J. (2013). This is How Your Brain Becomes Addicted to Caffeine. Smithsonian Magazine. Retrieved from:

[7] Rivers, A. (2018) Caffeine Overdose: How Much is Too Much? Healthline. Retrieved from:

[8] Can you Overdose on Caffeine? (2019) Medical News Today. Retrieved from:

[9] Stockton, T. (2004). Caffeine Withdrawl Recognized as a disorder. Johns Hopkins Medicine. Retrieved from:

[10] Saleh, N. (2019) 10 Surprising Health Benefits of living caffeine-free. MDLinx. Retrieved from: