Follow U.S. Investment Immigration and Life in the U.S.: The United States neuroscientists at the University of Maryland's Health Sciences Unified Services have calculated that the optimal time to drink coffee is between 9:30 AM and 11:30 AM. This is because the interaction effect of caffeine with a crucial hormone in the human body (cortisol, also known as hydrocortisone) reaches its peak during this period. Cortisol helps the body regulate its biological clock and enhances alertness. Cortisol levels peak shortly after waking up and can remain elevated for up to an hour, with an average peak occurring between 8 AM and 9 AM. Researchers believe that drinking coffee after this peak is more effective, as it can stimulate cortisol production when its levels begin to decline.
Additionally, drinking coffee when cortisol levels are at their highest can lead to tolerance to caffeine, meaning that one would need to consume more coffee to achieve the desired alertness effect. There is a similar perspective in pharmacology, which suggests that medications should be taken when they are most needed; otherwise, the body may develop resistance. In other words, drinking coffee at breakfast may not yield significant alertness effects.
Researchers also point out that while cortisol levels peak between 8 AM and 9 AM, they will peak again around noon (12 PM to 1 PM) and in the late afternoon (5:30 PM to 6:30 PM). Furthermore, cortisol levels can vary based on individual physiology and daily routines, suggesting that those who wake up later should consume coffee later in the day.