Effect of breath-hold on the responses of arterial blood pressure and cerebral blood velocity to isometric exercise

Purpose: The present study examined the effect of breath-hold without a Valsalva maneuver during isometric exercise on arterial blood pressure (ABP) and cerebral blood flow (CBF). Methods: Twenty healthy adults (15 men and five women) randomly performed only breath-hold without a Valsalva maneuver (BH), and an isometric handgrip exercise for 30 s at 40% of individual maximal voluntary contraction with continuous breathing (IHG) and with breath-hold without the Valsalva maneuver (IHG–BH). Mean ABP (MAP) and blood velocity in the middle (MCA V_mean) and posterior cerebral arteries (PCA V_mean) were continuously measured throughout each protocol. Results: MAP was elevated during the IHG–BH compared with IHG (P < 0.001) and BH (P = 0.001). Similarly, both MCA V_mean and PCA V_mean were higher during IHG–BH compared with IHG and BH (all P < 0.001). Moreover, the relative change in MAP from the baseline was correlated with that in both cerebral blood velocities during the BH (MCA V_mean: r = 0.739, P < 0.001 and PCA V_mean: r = 0.570, P = 0.009) and IHG–BH (MCA V_mean: r = 0.755, P < 0.001 and PCA V_mean: r = 0.617, P = 0.003) condition, but not the IHG condition (P = 0.154 and P = 0.306). Conclusion: These results indicate that during isometric exercise, a breath-hold enhances an exercise-induced increase in MAP and, consequently, MCA V_mean and PCA V_mean.