The reliability of psychophysiological examinations under field conditions: results of repetitive mental stress testing in middle-aged men.

In an epidemiological examination outside specialized laboratories we investigated the test-retest stability of blood pressure (BP) and heart rate (HR) reactions to standardized mental stress in 136 men (mean age 44 +/- 7 years) with complaints of mental and physical fatigue. Repetitive stress testing was performed at 4-week intervals on four occasions. On all four occasions stress levels differed significantly from baseline levels (P less than 0.001). Baseline conditions for BP and HR were significantly correlated at 4-week and 8-week intervals (P less than 0.001). Cardiovascular reactivity to mental stress was also stable over a 4, 8, and 12-week period. We conclude that psychophysiological reactivity can be assessed with good reliability under field conditions.