Objective: To test the hypothesis that enhanced post-exercise vasodilatation is related to sympathetic drive to resistance vessels and to fast marathon performance.
Design: Prospective field study before and after running a marathon.
Participants: 51 healthy amateur runners who volunteered to participate. The fastest finished 4th, the slowest 1290th out of 1324 participants.
Main Outcome Measurements: Competition time, beat to beat blood pressure by the vascular unloading technique, oscillometric blood pressure, beat to beat stroke volume by impedance cardiography, total peripheral resistance changes calculated from blood pressure and stroke volume changes, sympathetic modulation of vasomotor tone and parasympathetic modulation of sinus node function by spectral analysis of blood pressure and heart rate variability, baroreceptor reflex sensitivity by the sequence method.
Results: Slow performers in contrast to fast performers exhibited a higher 0.1 Hz band of diastolic blood pressure variability before the competition (0.1 Hz BPV) (P<0.001), diminished vasodilatation (P<0.01) and a decrease in stroke index (P<0.001) in response to the race. Single and multiple regression analyses further corroborated the findings.
Conclusions: Fast performance in the marathon is associated with low sympathetic modulation of vasomotor tone, maintained stroke index post-competition and enhanced exercise-induced vasodilatation. We postulate that maintaining a low level of sympathetic modulation to resistance vessels during the course of training may indicate it’s appropriateness thus enabling fast performance by optimal post-exercise vasodilatation and by prevention of post-competition cardiac dysfunction. This will have to be tested in future longitudinal studies.
- Autonomic Nervous System