90% of Americans consume caffeine daily. Chances are, you’ve probably had a cup of coffee, tea, or soda today. Caffeine consumption is something that is so deeply ingrained in so many of us that we feel as if we can’t function the same without it.
So, let’s take a deeper look at this “miracle molecule” to understand how it interacts with our brains and how we can better take advantage of it.
Numerous studies have shown the physiological benefits of caffeine. Following a period of a lack of sleep, the ingestion of caffeine can significantly improve information processing¹, memory², reaction time, alertness, and overall executive brain function³. Studies have even shown that caffeine can enhance long-term memory, where consuming caffeine after learning something new can help that knowledge be integrated into your memory more efficiently⁴.
But how exactly does caffeine work with our bodies?
The stimulating effect of caffeine occurs because of the way it interacts with adenosine receptors in the brain. Adenosine is an organic compound that slows neural activity. When it binds to its receptors, you feel lethargic and unfocused. Without caffeine or sleep, more and more adenosine will bind to receptors and create a positive feedback loop that eventually becomes exhaustion.
However, when you consume coffee or tea, caffeine gets absorbed through the small intestine and into the bloodstream, where the molecule travels to the central nervous system. There, caffeine binds to adenosine receptors and prevents adenosine from binding. Caffeine essentially takes up the space that adenosine would typically occupy and prevents your body from feeling the effects of sleepiness.
Additionally, caffeine activates a multitude of neural pathways in our bodies that cause the secretion of hormones such as adrenaline and cortisol. Both of these hormones increase our attention levels and provide us with the burst of energy that we associate with caffeine⁵.
Knowing all of this, how can we optimize the effects of caffeine to improve productivity and our workflow?
Consume Caffeine at the Right Time
Most people tend to drink coffee in the mornings, right when they wake up. However, science says that you probably shouldn’t be consuming caffeine at that time. Caffeine increases cortisol secretion, which is what gives us a boost of energy. When we first wake up in the mornings, our bodies naturally secrete cortisol to jumpstart our day. If we drink coffee or tea as well, we don’t give the caffeine any chance to be effective. In fact, you might run the risk of building up a caffeine tolerance or creating a feedback loop that prevents your body from naturally secreting cortisol⁶.
Assuming you wake up at around 7 AM, your maximum cortisol output will be around 8 or 9 AM. This means you should try to avoid consuming caffeine in that time frame. Instead, opt for waiting two to three hours after you wake up to have your first cup of coffee or tea.
Throughout the day, cortisol levels will rise and drop. Typically, the two next largest peaks of cortisol occur from noon to 2 PM and from 6 to 8 PM⁷. These peaks occur after you have a meal, following a spike in blood sugar. This means that we should avoid consuming caffeine during these periods. If you are someone who tends to go for a pick-me-up sometime in the afternoon, try to schedule that at around 3 or 4 PM, where there is a lull in your blood sugar and enough time has passed since lunch.
Another caffeine tip is to combine caffeine consumption and naps. We know that adenosine is the molecule that induces sleepiness. Sleeping actually clears the buildup of adenosine in its receptors, giving us a clean slate once we wake up. Combining this and the fact that caffeine prevents adenosine from binding means that we can amplify the effects of caffeine with naps.
If you consume caffeine and take a twenty-minute nap immediately after, you essentially double up on the benefits of caffeine and sleep. It takes about 20 minutes for caffeine to be digested and to reach your brain. After consuming caffeine and a 20-minute nap, adenosine is no longer clogging up your brain and caffeine is ready to prevent any further binding, allowing you to feel awake at the moment and stay alert for longer. 20 minutes is also just enough time for you to feel rested but not lethargic because you haven’t yet entered into a deep sleep.
As the most commonly used stimulant, caffeine is something many of us cannot live without. Try these tips to maximize its effects and reap the full benefits of it.
Kamimori, G. H., McLellan, T. M., Tate, C. M., Voss, D. M., Niro, P., Lieberman, H. R. (2015). Caffeine improves reaction time, vigilance and logical reasoning during extended periods with restricted opportunities for sleep. Psychopharmacology, 232, 2031-2042, doi.org/10.1007/s00213-014-3834-5.
Cunha, R. A., Agostinho, P. M. (2010). Chronic Caffeine Consumption Prevents Memory Disturbance in Different Animal Models of Memory Decline. Journal of Alzheimer's Disease, 20(1), 95-116, DOI: 10.3233/JAD-2010-1408.
Irwin, C., Khalesi, S., Desbrow, B., McCartney, D. (2020). Effects of acute caffeine consumption following sleep loss on cognitive, physical, occupational and driving performance: A systematic review and meta-analysis. Neuroscience & Biobehavioral Reviews, 108, 877-888. doi.org/10.1016/j.neubiorev.2019.12.008.
Lovallo, W. R., Whitsett, T. L., al'Absi, M., Sung, B. H., Vincent, A. S., & Wilson, M. F. (2005). Caffeine stimulation of cortisol secretion across the waking hours in relation to caffeine intake levels. Psychosomatic Medicine, 67(5), 734–739. doi.org/10.1097/01.psy.0000181270.20036.06.
Chan, S., & Debono, M. (2010). Replication of cortisol circadian rhythm: new advances in hydrocortisone replacement therapy. Therapeutic Advances in Endocrinology and Metabolism, 1(3), 129–138. doi.org/10.1177/2042018810380214.