Cardiovascular effects of coffee and caffeine

Area of Science:

• Cardiovascular Physiology
• Pharmacokinetics

Background:

• Caffeine is a widely consumed stimulant with known physiological effects.
• Individual responses to caffeine can vary based on consumption habits, smoking status, and intolerance.

Purpose of the Study:

• To evaluate the cardiovascular effects of coffee and caffeine.
• To assess the elimination kinetics of caffeine in different user groups.
• To determine if daily caffeine consumption, smoking, or intolerance influences cardiovascular response.

Main Methods:

• 54 volunteers were categorized by daily caffeine intake, smoking status, and caffeine intolerance.
• Subjects underwent a 24-hour caffeine abstinence period.
• Cardiovascular parameters (blood pressure, heart rate, systolic time intervals) and plasma caffeine levels were measured after administration of coffee and a standardized caffeine dose (2.2 mg/kg).

Main Results:

• Both coffee and caffeine produced similar cardiovascular effects.
• Average systolic/diastolic blood pressure increased by 9/10 mm Hg.
• Heart rate decreased by an average of 10 beats/min, with minor increases in systolic time intervals.
• Caffeine half-life was shorter in smokers and heavy users (3.2-4.1 hours) compared to non-smokers and non-users (5.1-5.3 hours).
• The caffeine-intolerant group showed a longer half-life but similar cardiovascular responses.
• No significant cardiovascular differences were found among the different volunteer groups.

Conclusions:

• Cardiovascular responses to coffee and caffeine are consistent across varying consumption levels, smoking statuses, and caffeine intolerance.
• Caffeine tolerance, if diminished by a 24-hour abstinence, is fully restored.
• Individual factors like smoking and consumption habits primarily affect caffeine elimination kinetics rather than acute cardiovascular effects.