Spilling the beans: Are you drinking too much caffeine?

Investigating Caffeine Dependence Among University Students (and how to fix it)

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As the first term of my final year is coming to an end, I can confidently say it was a whirlwind. Between graduate job applications, assignment deadlines, part-time jobs, and extracurriculars, it felt like a nonstop race. During this chaos, I often found myself reaching for a cup of coffee- more times than I’d like to admit. I knew it was a problem when my sleep schedule became erratic, and I know I'm not alone in this. That’s why I decided to dive deeper into how caffeine affects us and what we can do to fix it.

What is sleep, and why do we need it? 

Did you know we spend about one third of our life asleep? (2) That’s why getting it right is so important. Sleep is universal for anyone with a nervous system, and although researchers don’t know its exact biological purpose, they’ve linked it to benefits like improving the immune system, cognition and even, from an evolutionary standpoint. 

Figure 1. Theories as to why we sleep.

How much caffeine is too much?

Feel like you can’t stop drinking coffee? Don’t blame yourself. In fact, caffeine is globally the most commonly consumed psychoactive substance- meaning it directly changes brain function and alters your mood, behaviours etc. Sounds familiar? Its similar to substances like alcohol and nicotine (7).

An interesting study (1), reported 93% of US college students consumed caffeine, with men averaging 120 mg per day and women 111 mg. The Mayo Clinic recommends 400 mg per day as the safe limit for most healthy adults (8). 

Figure 2. Caffeine chart from Handbook of substance misuse and addiction (6). 

The battle between sleep and caffeine 

Have you noticed, the longer you stay awake, the more desperate your body becomes for sleep? That’s because of sleep pressure. Its regulated by a brain molecule called adenosine, that increases the urge to sleep as the day goes by. A special type of brain cell called astrocytes releases 2 types of chemicals: adenosine and glutamate. However, glutamate does the opposite of adenosine and keeps our brain active and alert (11).  Figure 3. How caffeine helps you stay awake. (9)

Check out this awesome video by TED-Ed on this!

How does sleep deprivation affect us? 

Is one night of bad sleep really a big deal? Absolutely. Reachers investigated the effects of short term sleep deprivation and found that in just 24 hours of sleep deprivation, can wreak havoc on both your mental and physical health (10).

• Mood changes: Heightened negative emotions such as confusion, fatigue, depression and anxiety. 

• Cognitive decline: Reduced attention and working memory. 

• Inflammation: Linking sleep deprivation to immune system issues. 

• Stress hormone (cortisol): Increase in cortisol levels, indicating higher stress. 

These findings emphasise just how critical sleep is for overall well-being. If this doesn't convince you to prioritise sleep, I don't know what will! 

What can we do about it? 

Let's be real: You probably already know you need 7-9 hours of sleep. The issue isn’t a lack of information, it’s actually putting it into practice. Here are some tips: 

• Managing your caffeine intake: You don’t have to quit cold turkey. In fact, with moderate consumption, there are reported health benefits, like reducing risks of neurodegenerative disorders and heart diseases (12). As long as you avoid it close to bedtime, so as your body has time to break it down. 

• Addressing the underlying issues:

  - Could there be another reason why you have to sacrifice your sleep so much? Try better time management tools like Google Calendar or a student favourite- Notion. 

  - If you’re struggling, don’t hesitate to seek help. Most universities offer counselling services or mentoring in academic work. 

  - Make time for yourself. Join a campus society or prioritise physical break to elevate that stress. 

• Embrace Technology: Explore sleep apps or health- tracking gadgets like the Oura ring, which provides personalised recommendations for improving sleep habits. They help identify patterns and make adjustments- perfect for a cheeky Christmas gift request! 

Take the first steps to implement better habits, you can start next year and term with a bang! So, how much coffee did you drink today? 

References:

1. Mahoney CR, Giles GE, Marriott BP, Judelson DA, Glickman EL, Geiselman PJ, et al. Intake of caffeine from all sources and reasons for use by college students. Clinical Nutrition [Internet]. 2019 Apr;38(2):668–75. Available from: https://pubmed.ncbi.nlm.nih.gov/29680166/

2. Aminoff MJ, Boller F, Swaab DF. We spend about one-third of our life either sleeping or attempting to do so. Handbook of clinical neurology [Internet]. 2011;98:vii. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21056174

3. Hablitz LM, Plá V, Giannetto M, Vinitsky HS, Stæger FF, Metcalfe T, et al. Circadian control of brain glymphatic and lymphatic fluid flow. Nature Communications [Internet]. 2020 Sep 2;11(1):4411. Available from: https://www.nature.com/articles/s41467-020-18115-2#ref-CR15

4. Brinkman JE, Sharma S, Reddy V. Physiology of Sleep [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482512/

5. Siegel JM. Sleep viewed as a state of adaptive inactivity. Nature Reviews Neuroscience. 2009 Aug 5;10(10):747–53.

6. Gabrielle Rabelo Quadra, Emília Marques Brovini, Andreia J, Paranaíba JR. Caffeine Consumption over Time. Springer eBooks. 2022 Jan 1;1535–52.

7. Temple JL, Bernard C, Lipshultz SE, Czachor JD, Westphal JA, Mestre MA. The safety of ingested caffeine: A comprehensive review. Frontiers in Psychiatry. 2017 May 26;8(80).

8. Mayo Clinic. Caffeine: How much is too much? [Internet]. Mayo Clinic. Mayo Foundation for Medical Education and Research; 2022. Available from: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20045678

9. Reichert CF, Deboer T, Landolt H. Adenosine, caffeine, and sleep–wake regulation: state of the science and perspectives. Journal of Sleep Research [Internet]. 2022 May 16;31(4). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9541543/

10. Thompson KI, Chau M, Lorenzetti MS, Hill LD, Fins AI, Tartar JL. Acute sleep deprivation disrupts emotion, cognition, inflammation, and cortisol in young healthy adults. Frontiers in Behavioral Neuroscience. 2022 Sep 23;16.

11. Summer J. Adenosine and Sleep [Internet]. Sleep Foundation. 2022. Available from: https://www.sleepfoundation.org/how-sleep-works/adenosine-and-sleep

12. Hopkins J. 9 Reasons Why (the Right Amount of) Coffee Is Good for You [Internet]. John Hopkins Medicine. 2019. Available from: https://www.hopkinsmedicine.org/health/wellness-and-prevention/9-reasons-why-the-right-amount-of-coffee-is-good-for-you