BIOBEHAVIORAL EFFECTS OF CAFFEINE IN MEN

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The investigators will use the blood pressure, cortisol, and cognitive performance measures to develop complex computer models of how people respond to challenge. It is hypothesized that blood pressure and cortisol levels will increase as caffeine consumption increases. In contrast, task performance will be maximized at the low dose of caffeine, and impaired at the high and control (zero) levels of caffeine intake. One-hundred and thirty five healthy, non-smoking young men (aged 18-30 yrs) will come to the laboratory for a 2-hr laboratory session at which time they will be administered one of three doses of caffeine: none (placebo), 200 mg caffeine (equivalent to 1-2, 8 ounce cups of caffeinated coffee), or 400 mg caffeine (equivalent to drinking 3-4, 8 ounce cups of caffeinated coffee). Next, participants will be asked to participate in 1 of 3 cognitive tasks: a serial subtraction task, a computerized 3-D driving task, or a computerized decision-making task similar to an air traffic control simulator. Their blood pressure and heart rate will be measured throughout the study, and they will be asked to provide a saliva sample before and after the tasks to determine their cortisol (a hormonal indicator of stress) responses to the challenge. Data from all participants will be averaged and used to create computer models of cognitive performance, blood pressure responses, and cortisol levels following different levels of caffeine consumption. These computer models will be used to summarize human behavior and to provide important information about vulnerability to stress-related illnesses, such as high blood pressure.