Your eyes try to close, but no, you have to stay awake. You are finishing an essay due at 8:05 a.m., and glancing at the clock that reads 1:00 a.m. Well, it is probably too late to ask for an extension now. Suddenly, that Monster energy drink in the fridge starts to look pretty good. In the morning, you are exhausted and oh, you just realize you have that math test in the afternoon. Yeah, there is no way you are getting through that without dozing off, so you make a quick run to Starbucks to get a nice iced caramel macchiato. You crash at the end of the day onto your bed, the cycle starting all over again.
For many high schoolers, reaching for that nice cup of coffee seems like the perfect solution to a lack of time in a busy schedule. However, all high school students have probably heard that they should not drink coffee, whether from a parent or someone online saying “It affects your sleep” or “It is addictive.” But what effect does caffeine have on your body that makes it so “bad” for you?
When someone drinks coffee, the caffeine in the drink is absorbed into the bloodstream, traveling through your body. The caffeine molecules then cross your blood-brain barrier, where they bind to the adenosine receptors in the brain. Adenosine is a natural chemical in your body that acts like a “sleepiness signal.” Usually, adenosine binds to these adenosine receptors, which signal to the brain to promote sleep. However, these adenosine molecules are blocked by the caffeine that attaches to these receptors, preventing this message of sleepiness from reaching the brain. Furthermore, this interference with the receptor also releases several neurotransmitters: norepinephrine, which increases alertness and heart rate; serotonin, which makes you happier and calmer; acetylcholine, which plays a role in memory and attention; and dopamine, which improves your mood and helps with memory.
However, these benefits only last a few hours. As a result of the interference, your body starts producing more adenosine receptors, and once that caffeine starts to be metabolized and removed from the body, the increased amount of receptors starts binding with adenosine, making you fatigued. This is also how caffeine addiction develops, as individuals who drink coffee regularly have increased levels of adenosine receptors, needing more caffeine to block adenosine and feel awake.
For adolescents, the effects of caffeine are more severe than for adults since their brains are still developing. In adolescents, caffeine can cause higher blood pressure, insomnia, a faster heart rate, and increased anxiety.
That said, caffeine has its pros and cons. In moderation, it can be a helpful tool, but maybe next time, try to prioritize sleep instead.
Works Cited
“Acetylcholine (ACh).” Cleveland Clinic, 25 Sept. 2025, my.clevelandclinic.org/health/articles/24568-acetylcholine-ach.
“Is Coffee Bad for Kids?” Johns Hopkins Medicine, 23 July 2024, www.hopkinsmedicine.org/health/wellness-and-prevention/is-coffee-bad-for-kids.
Juárez Olguín, Hugo, et al. “The Role of Dopamine and Its Dysfunction as a Consequence of Oxidative Stress.” Oxidative Medicine and Cellular Longevity, 6 Dec. 2015, https://doi.org/10.1155/2016/9730467.
“Norepinephrine.” Cleveland Clinic, 11 Sept. 2025, my.clevelandclinic.org/health/articles/22610-norepinephrine-noradrenaline.
“Pharmacology of Caffeine.” National Library of Medicine, 1 Jan. 1970, www.ncbi.nlm.nih.gov/books/NBK223808/.
Sajadi-Ernazarova, Karima R., and Richard J. Hamilton. “Caffeine Withdrawal.” National Library of Medicine, U.S. National Library of Medicine, 8 Aug. 2023, www.ncbi.nlm.nih.gov/books/NBK430790/.
“Serotonin: What Is It, Function & Levels.” Cleveland Clinic, 22 Sept. 2025, my.clevelandclinic.org/health/articles/22572-serotonin.
