The effects of caffeine on physiological functions and mental performance

Area of Science:

• Psychology
• Neuroscience
• Pharmacology

Background:

• Caffeine is a widely consumed psychoactive substance.
• Its effects on cognitive functions and physiological responses are of significant interest.
• Understanding dose-dependent effects is crucial for public health.

Purpose of the Study:

• To investigate the impact of a moderate dose of caffeine (300 mg) on mental performance and physiological variables.
• To differentiate between effects on cognitive functions versus behavioral routine and speed.
• To assess vegetative side effects associated with caffeine consumption.

Main Methods:

• A double-blind, placebo-controlled study design was employed.
• Participants (N=48) were divided into four groups: caffeine, decaffeinated coffee, warm water, and no beverage.
• Polygraphic monitoring of physiological variables (heart rate, respiration, muscle tension, skin conductance, acrodermal blood flow) was conducted during cognitive and performance tasks (mental maze, letter cancellation).

Main Results:

• Caffeine administration led to increased regularity and speed in the letter cancellation task, indicated by reduced intraindividual variance.
• A slight but significant acrodermal vasoconstriction was observed in the caffeine group.
• No significant differences were found between groups in mental maze learning performance, heart rate, respiration, muscle tension, or skin conductance.

Conclusions:

• Caffeine at a 300 mg dose primarily enhances behavioral routine and speed rather than higher-level cognitive functions.
• The observed physiological side effects (acrodermal vasoconstriction) are minimal at this dose.
• These findings suggest a specific mechanism of action for caffeine related to performance efficiency in repetitive tasks.