Attempting to exhale forcefully into closed airways constitutes the valsalva maneuver.

As a result the pressure within the thorax rises and the thoracic aorta is compressed. The diameter mismatch between thoracic and abdominal aorta is reduced and the reflected pulse from that site (P2) is diminished in amplitude during the maneuver.

Due to the overall drop in arterial pressure, propagation velocities drop and the time between P1 and P3 (T13) narrows during the maneuver.

These changes in the central arteries can be observed at the radial artery, as explained on the previous pages.

The valsalva maneuver commences about 1/3 into the time scan shown and ends just before the scan finishes:

Observe how P2 decreases in amplitude relative to P1 (P2/P1 ratio change from about 0.60 to 0.27).

Observe the narrowing of T13 by about 70 milliseconds.

One Second Time Window

T13 time delay

(milliseconds)

P2/P1 ratio (unitless)

Heartbeat pulse changes at the radial artery site (wrist) due  to valsalva