Abstract

We have been investigating selected effects of caffeine on the cardiovascular system of young adults for the past several years [1-4]. The young adults have been enrolled in courses such as Systems Physiology (01:146:346), Systems Physiology Laboratory (01:146:357), and Advanced Physiology (01:146:456) at Rutgers University. We selected young adults because there has been little effort by the medical/scientific communities to investigate their cardiovascular health; and, because there should be little doubt that the cardiovascular health of young adults is changing in the current obesity/overweight pandemic (circa post-1990). We have found that caffeine increases peripheral vascular resistance (1-4) and markedly reduces peripheral blood flow [1-4]. Caffeine also attenuates reactive hyperemia [2] and pressure-flow autoregulation [3]. The current experiment is a follow up to examine caffeine’s effects on the peripheral circulation of the toes. After four minutes of zero-flow occlusion, reperfusion (reactive hyperemia) was monitored for sixteen minutes. In all students reactive hyperemia was markedly and significantly reduced by caffeine, reflecting attenuation of the regulation of pedal arterial blood supply. These results are consistent with our prior experiments and demonstrate the potentially harmful effects of caffeine on the cardiovascular system of young adults.