Hemodynamic adjustments to circulatory arrest during and following isometric handgrip in resistance trained and untrained men.

AIM

We attempted to isolate the effects of central command (CC) and the muscle metaboreflex (MR) on hemodynamics during and following fatiguing isometric handgrip (IHG) with circulatory arrest in 9 male weightlifters (WL) and 11 age-matched controls (C).

METHODS

Hemodynamics were recorded at rest, during fatiguing IHG at 40% MVC with occlusion, and during post-IHG occlusion. Blood pressures were measured by auscultation and stroke volume by impedance cardiography.

RESULTS

Hemodynamic adjustments due to CC were determined from the difference (fatigue post-IHG occlusion) in measures at fatigue during IHG (CC+MR effects) and during post-IHG occlusion (MR effect). Hemodynamic adjustments due to the MR were determined from the difference (post-IHG occlusion rest) in measures during post-IHG occlusion and at rest. The peak adjustment (due to CC+MR) in systolic blood pressure (44.6+/-12.9 vs 33.8+/-6.2 mmHg, P=0.02) and the adjustments (due to CC) in diastolic (13.8+/-7.6 vs 6.9+/-5.1 mmHg, P=0.02) and mean arterial blood pressures (14.9+/-7.8 vs 8.7+/-4.6 mmHg, P=0.04) were significantly greater in WL than C. However, there were no significant (P>0.05) group differences in hemodynamic adjustments (due to MR) to post-IHG occlusion.

CONCLUSION

We conclude that weight training may result in significantly greater CC effects on peak pressor responses to moderately intense, fatiguing isometric actions with circulatory arrest.