Fig. 1

Typical trace for a combination of RE and VM (RE + VM), Valsalva manoeuvre (VM) in isolation, and isometric RE in isolation (RE). Phases of the VM (phase I (PI) through phase 4 (PIV)) are visible in both RE+VM and VM conditions. The thick black line in middle cerebral artery blood velocity (MCAv), posterior cerebral artery blood velocity (PCAv) and arterial blood pressure (ABP) traces represents the mean value for each cardiac cycle. HR heart rate. Reproduced with permission from [45]