A test of generalizability of cardiovascular reactivity using a controlled ambulatory procedure.

This study tested the hypothesis that reports of poor generalizability of cardiovascular reactivity measured in the laboratory to changes observed during everyday life are due to a lack of standardization of activities and position (sitting, standing) in the latter situation. Thirty-seven subjects engaged in reactivity testing, and then in a 4-hour series of standardized activities outside the laboratory (controlled ambulatory phase), accompanied by the experimenter, on each of 2 days. The controlled ambulatory activities included alphabetizing, an editing task, a brisk walk, solving word puzzles, and eating lunch. Two measures of field variability were examined: the standard deviation and the root mean square of successive differences, of all ambulatory measurements. Associations between laboratory changes scores and measures of field variability were poor (highest r = .23). We conclude that evidence for generalizability of reactivity change scores remains poor, and cannot be solely attributed to the uncontrolled nature of activities in the field.

Duke Scholars

Author Carl F. Pieper Biostatistics & Bioinformatics, Division of Biostatistics