The purpose of this study was to investigate the short-, medium- and long-term reproducibility of cardiovascular responses during 90... head-up tilt (HUT) in healthy older men. Twenty-eight healthy male subjects aged 69 (95... confidence intervals, 68-70) years participated in the study. Eight subjects underwent duplicate 90... HUT tests on consecutive days, while 20 subjects underwent four 90... HUT tests performed at baseline, and after 1 week, 1month and 1 year. Following a 20-min supine resting period, each subject was rapidly tilted to the upright vertical position (90... HUT) and remained in that position for 15 min. Beat-by-beat recordings of mean (MAP), systolic (SBP) and diastolic (DBP) pressures were made via Finapres, while heart rate (HR) was monitored continuously from an electrocardiogram. No significant test-retest differences (P...0.05) were observed for the changes in HR, MAP, SBP or DBP during 90... HUT. These measurements demonstrated high reproducibility (intraclass correlation coefficient, r ... 0.91-0.99, P ...0.05). The supine resting and tilted HR, MAP, SBP and DBP over the 1-week, 1-month and 1-year period were not significantly different (P ...0.05) frombaseline, and demonstrated high reproducibility (intraclass correlation coefficient, r ...0.82-0.98, P ...0.05). The results of this study demonstrate that in healthy older men, cardiovascular responses during orthostasis are highly reproducible, and this reproducibility is maintained over a 12-month period. These findings demonstrate that the 90... HUT test offers a reproducible method of monitoring longitudinal orthostatic responses in healthy older men.