In this study we investigated whether body position has significant effects on baroreflex sensitivity in healthy subjects. Baroreflex sensitivity was calculated from pressure overshoot after the release of a Valsalva strain in the supine and sitting positions in 10 subjects. At rest, no difference was found in supine and sitting mean R-R intervals (837 +/- 82 and 858 +/- 86 ms, respectively), whereas systolic and diastolic blood pressures were lower in the supine position (111.3 +/- 24.6 vs. 141.2 +/- 12.6 mmHg, P < 0.01 and 54.8 +/- 14.7 vs. 75.6 +/- 13.4 mmHg, P < 0.001, respectively). Baroreflex sensitivity in the supine (9.0 +/- 4.1 ms x mmHg-1) and sitting positions (8.8 +/- 4.9 ms x mmHg-1) did not differ significantly from each other. The correlation between supine and sitting baroreflex sensitivity was 0.96 (P < 0.001) and in 9 out of 10 subjects the discrepancy between supine and sitting baroreflex sensitivity was < 2.0 ms x mmHg-1. We conclude that baroreflex sensitivity measured in the supine and sitting positions do not differ significantly from each other.