It is a stimulating, indulgent drink at any time of day, for anyone: Coffee. But opinions differ on whether it is as healthy as people think. The caffeine contained in coffee is said to have a strong effect on brain performance. This raises the question of whether - and if so, when - is the best time for the brain to consume its daily dose?

The fact is: Whether there is a right time to get the most out of caffeine's wake-up effect is not so easy to answer. It varies from person to person. But there are some neurobiological factors that can be used as a guide. For example, the stress hormone cortisol - and this is the core issue here - has a positive, activating effect. Like caffeine, it inhibits adenosine receptors. Adenosine makes us feel tired. At the same time, it stimulates the release of other activating neurotransmitters such as epinephrine, norepinephrine, and dopamine.

The hypothalamus controls the release of cortisol. Cortisol levels drop during the first half of the night to allow us to recover. Then, starting around midnight, cortisol levels rise again, peaking about 30 minutes after you wake up and get out of bed. That's usually between six and seven in the morning. This makes sense because that's when we want to be active. After that, the level slowly drops.

In a healthy body, all hormones are released in a certain rhythm throughout the day, the circadian rhythm. Our organism synchronizes the physiological processes to a length of about 24 hours. Our brain actually wants regular processes: to wake up at the same time and go to sleep at the same time. So if we want to get an extra boost from a cup of coffee, it makes sense to do it when the cortisol level naturally drops. This is usually three to four hours after getting up. Scientifically speaking, the optimal time to drink coffee is between nine and ten o'clock in the morning.

However, this cannot be generalized. Of course, you can try and optimize it. Many people drink their first coffee or espresso right after breakfast or right after getting up out of habit. Our brains are then used to getting caffeine at the expected time. Cultural habits effectively override biological rhythms. If you want to optimize your caffeine intake and adapt it to your natural rhythm, you can even expect to have less energy at first as you make the change. The transition would take a few days. And, of course, you would have to figure out what your biological rhythm is.

And caffeine can also have an opposite or even counterproductive effect. This is because cortisol is released as needed, especially during times of stress. In people with depression or burnout, this can lead to cortisol levels not dropping at all.