Perhaps the most typical morning in America starts with an alarm clock, a yawn and a cup of coffee. Much of the world has come to associate coffee with a morning pick-me-up—an energy boost that can catalyze your brain and body into action and kickstart an energetic workday. Surprisingly, science—specifically a branch of pharmacology called chronopharmacology, the study of the interplay of biorhythms and drug action—has a different take than popular culture on just when caffeine intake is most (and least) effective.
The Effect of Caffeine on Your Day
Caffeine is the most popular psychoactive drug on earth—ninety percent of the world consumes it in at least one meal or beverage each day. The caffeine leaders are the United States (971 tons per year), followed closely by Brazil (969 tons). The main reason caffeine is so popular is the beans, leaves and fruit of over 60 plants; through exportation, these find their way to most nations on earth. However, nearly 70% of world caffeine consumption is in the form of coffee.
The Science Behind Caffeine And Biorhythms
Neuroscientist Greg A. Dunn suggests that the body’s production of cortisol, a natural steroid hormone, is a crucial factor in determining the ideal time to consume caffeine. Cortisol secretion in the human body peaks around 8 or 9 a.m. due to the relationship between increased light (daytime hours) and the hypothalamus, the part of the brain that regulates circadian rhythm, the bodies’ 24-hour timing mechanism. Essentially, this implies that most people choose to drink coffee at a time when they are naturally most alert anyway. Besides the obvious inefficiency involved, this practice also tends to increase tolerance of caffeine, which in turn encourages more use of it in order to achieve the desired stimulation level. Morning may actually be one of the worst times to drink coffee!
How To Use The Body’s Natural Cortisol Peaks
That morning cortisol jolt isn’t the only spike on the daily graph. There is also a medium surge between noon and 1 p.m., and then another small one between 5:30 and 6:30 p.m. (cortisol release is also shown to be associated with—though not dependent on—mealtimes). Therefore, consuming caffeine during these timeframes is somewhat redundant— the body is already generating the energy and alertness we need, so the effect of the drug is wasted.
The best time to get the maximum effect of your coffee is between 9:30 and 11:30 a.m., when the morning cortisol peak has diminished. Another is early afternoon, when the circadian clock naturally begins to lag. Other cultures have devised their own customs for the afternoon cortisol dip—the British have historically instituted a small caffeine jolt (“tea-time”) for the late afternoon hour; other countries such as Spain go in the opposite direction and embrace the biorhythmic dip with a siesta or midday nap, choosing to sleep off the day’s least productive hours and make up the time afterwards (Spanish suppers are often served as late as 9 PM).
So when it comes to caffeine, you may have to decide if you’re feeling British (afternoon), Spanish (late morning), or American (throughout the day)!