Cardiovascular responses to occupational stress and caffeine in telemarketing employees

Cardiovascular responses to the combination of caffeine and a challenging occupational activity were examined using a within-subject, double-blind design. Seventeen female and 11 male telemarketing employees received drinks that did and did not contain 250 mg of caffeine on two consecutive days, with order of presentation counterbalanced across subjects. Repeated measurements of systolic and diastolic blood pressure, heart rate, and digital blood volume pulse were obtained during a pre-drug resting baseline and a post-drug working period on each day. Repeated measures analyses of variance revealed significant main effects of Period on all measures of cardiovascular activity, indicating that occupational demands elicited significant cardiovascular adjustments. Only systolic blood pressure revealed a significant Drug X Period effect, indicating that responses were significantly greater on the caffeine versus placebo day. The changes in diastolic blood pressure and heart rate, although not significant, were consistent in direction with the results from previous laboratory studies. There were no significant differences between males and females in cardiovascular response to the combination of stress and caffeine.