Received December 19, 2007
Revised January 9, 2008
Accepted after revision January 23, 2008
Cardiovascular Control [210]
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Hemodynamic effect of metaboreflex activation after running above and below the velocity of the anaerobic threshold
Antonio Crisafulli 1*,
Raffaele Milia 1,
Andrea Lobina 1,
Manuela Caddeo 1,
Filippo Tocco 2,
Alberto Concu 1,
Franco Melis 1
1 University of Cagliari
2 Uiversity of Cagliari
* To whom correspondence should be addressed. E-mail: crisafulli{at}tiscali.it.
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Abstract |
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Previous studies have shown that the muscle metaboreflex, along with its effect on peripheral vasculature, is capable of inducing substantial enhancement in cardiac performance, stroke volume (SV), and cardiac output (CO). This study was designed to determine whether the metaboreflex recruited by means of post-exercise muscle ischemia (PEMI) after running at two intensities was capable of eliciting similar enhancement in these cardiovascular parameters. In eight healthy male athletes the metaboreflex was studied with the PEMI method at the start of recovery from running bouts at the velocity of 30% above (PEMI-AVAT) or below (PEMI-BVAT) the anaerobic threshold previously assessed. Control exercise recovery tests at the same intensities were also conducted. Hemodynamics was evaluated by means of impedance cardiography. The main results were that :1) the PEMI-AVAT test induced an increase in SV, which was not present during the other protocol conditions; 2) the PEMI-AVAT test also induced a blunted HR response compared to the control situation; however, this relative bradycardia was fully compensated by the SV increment so that CO was maintained and even increased in comparison with the other protocol sessions; 3) finally, there was no detectable increase in systemic vascular resistance during PEMI-AVAT. These results provide evidence that, like what has previously been reported for small muscle mass exercise, metaboreflex activation after running is capable of enhancing cardiac performance and SV. Moreover, this study strengthens the concept that the cardiovascular response to metaboreflex is not merely the consequence of a systemic vascular resistance increase.
Key Words:
Blood pressure, Exercise
