Coffee cheers you up even without caffeine

Coffee refreshes the mind, even if there is no caffeine in it. That was found out in a study involving twenty students who drink coffee every day.

The researchers wanted to find out whether the effects of coffee stem from the caffeine itself or perhaps from expectations related to the coffee drinking routine. They divided the students into two groups, one of which received caffeinated coffee and the other a decaffeinated alternative that tasted and smelled exactly the same.

All participants believed they were drinking regular coffee. All had also gone without drinking coffee for eight hours before receiving it in the test.

Both before and after the cup of coffee, the students’ heart rate and blood pressure were measured. In addition, they performed simple cognitive tasks. The electrical activity of the brain was also measured.

Surprisingly the physiological effects of both types of coffee were exactly the same: heart rate decreased and blood pressure increased.

Calculation performance did not improve in either group. Instead, attention seemed to sharpen slightly after both drinks.

The only difference in the effect of the drinks was visible in the electroencephalogram. So caffeine caused changes in the brain, but they were not related to cognitive performance or heart function.

“When we’re used to caffeine and assume we’re getting it from a cup of coffee, decaffeinated coffee alone has almost the same effect on us,” explains the University of Novo Mesto in Slovenia to Psypost Mateja Lesarwho is one of the authors of the study.

Research published by Heliyon science magazine.

Published in Tiede magazine 10/2025.