Hironori Watanabe1, Takuro Washio1,2, Shotaro Saito1, Shigehiko Ogoh3,4. 1. Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan. 2. Japan Society for the Promotion of Science, Tokyo, Japan. 3. Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan. ogoh@toyo.jp. 4. Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK. ogoh@toyo.jp.
Abstract
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 Vmean) and posterior cerebral arteries (PCA Vmean) 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 Vmean and PCA Vmean 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 Vmean: r = 0.739, P < 0.001 and PCA Vmean: r = 0.570, P = 0.009) and IHG-BH (MCA Vmean: r = 0.755, P < 0.001 and PCA Vmean: 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 Vmean and PCA Vmean.
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 Vmean) and posterior cerebral arteries (PCA Vmean) 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 Vmean and PCA Vmean 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 Vmean: r = 0.739, P < 0.001 and PCA Vmean: r = 0.570, P = 0.009) and IHG-BH (MCA Vmean: r = 0.755, P < 0.001 and PCA Vmean: 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 Vmean and PCA Vmean.