26 June 2023

How many cups of coffee you have to drink to wake up

A low dose of caffeine suppresses alpha brain waves and improves executive function. The study was published in the journal Physiology & Behavior.

The study, conducted in Thailand using electroencephalography (EEG) and cognitive tests, showed that working memory improves after drinking a caffeinated beverage in the morning. In addition, EEG recordings showed a decrease in alpha wave activity. This is a type of brain activity often associated with sleepiness. Their levels were lower when compared to morning activity before drinking the caffeinated beverage.

The authors of a new paper investigated whether one low dose of caffeine as a morning drink affects brainwave activity and cognitive function. Thai researchers conducted the experiment on 25 healthy young men (average age 21) who typically consumed 1-2 or fewer cups of caffeinated coffee or tea or 1 can of caffeinated soda per day.

Participants were randomly divided into two groups and conducted a blinded placebo experiment. The test subjects visited the lab three times. At the first visit, researchers measured various parameters - weight, height, body fat percentage, and other indicators. The experiment was conducted during the second visit. Brain activity was measured for 5 minutes at rest in a sitting position with eyes closed using an EEG. Subsequently, participants performed two cognitive function tests.

Afterwards, each participant drank his or her cup of flavored water with or without caffeine (50 mg), depending on the group. After 30 minutes, the subjects had their brain activity measured again and performed cognitive tests. This was followed by 5-minute exercises and then another session of EEG and cognitive testing. A week later, the whole procedure was repeated, with the only difference being that the groups switched places.

The results showed that 30 minutes after taking caffeine, the average absolute power of the alpha waves decreased. Participants who took the placebo showed delta, beta, and theta wave activity. Cognitive function, that is, visual-motor processing speed, working memory, and attention improved after 30 minutes of caffeine consumption and after 35 minutes, where 5 minutes of isokinetic exercise were included. In other words, the brain activity responsible for drowsiness decreased and cognitive function improved 30 minutes after taking 50 mg of caffeine. This dose is almost analogous to one cup of espresso.

Notably, this is the first study to find an inverse correlation between alpha wave activity and cognitive function after a single low dose of caffeine.

The study did not measure other aspects of cognitive function, such as problem solving and decision-making. And, because the subjects this time were men only, the experiment will be conducted in the future to account for gender differences.
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