After breakfast, project staff carried out an experimental protocol assessing physiological response to, and recovery from, cognitive and orthostatic challenges similar to stressors people experience in their daily lives. The protocol consisted of a series of two randomized 6 minute cognitive challenges, one involving a math task and the other a Stroop-like test (decision-making about stimuli in which letters and colors are in conflict), followed by a 6 minute orthostatic (standing) challenge. Each challenge was followed by a 6 minute recovery period. Physiological reactivity throughout the experimental protocol was monitored via measures of blood pressure, heart rate variability and respiration, and salivary cortisol. Completed SAQs were then collected, and respondents were debriefed. At the UW-Madison data collection site, information was given about completing objective sleep assessments, to be returned by mail, after returning home. At the end of their visits, respondents were given a report about their blood pressure, body mass index (BMI), and waist-hip ratio. They were sent letters reporting cholesterol, HAlc, and bone density 1–2 months after the clinic visit.
To ensure consistency across sites and optimize the pace and quality of data collection, project staff and clinic nursing staff at all three sites followed standardized procedures that were detailed in a general Manual of Procedures, as well as more specific Guidelines for Collecting and Processing Biomarkers, and a Psychophysiology Manual. An administrative database was used to facilitate management and tracking of cross-project participation as well as tracking of participation at the three Project 4 sites. This information allowed review of participation information and quality control assessments, including identifying areas where additional staff training was required. Monthly conference calls with staff and investigators from all sites provided a forum to discuss issues or problems. Prior to these calls, each site generated a “Progress Report”, using report queries built into the administrative database; the reports were circulated for review by all on the conference call.