This is a simple test that can be performed by sitting down then exhaling as if trying to blow up a balloon or exhaling with the back of your hand on your mouth to cause resistance but not blocking the path of air completely.

THE TEST IS STANDARDIZED BY A PROFESSIONAL USING MEDICAL EQUIPMENT BY HAVING THE PATIENT EXHALE AT A PRESSURE OF 40mmHg.

This test is designed to force the blood to the arms from pressure. Once the test is completed the blood fills back up in the heart and lungs after a few heartbeats. The sudden pressure changes need to be navigated by the autonomic nervous system. Dysautonomia may cause irregularities in the blood pressure and heart rate when this occurs. The baroreflex continuous loop of signals between heart rate and blood pressure to balance each other out may not function correctly. When one goes up the other should go down. Blood pressure decreases in the heart while blowing then rapidly increases when you stop when the blood fills back in. The nervous system needs to rebound quickly and this may cause an over reaction in a damaged autonomic nervous system.

The highest heart rate during the test divided by the lowest heart rate 30 seconds after it will give you a Valsalva ratio. If this ratio is less than 1.4 it can mean there is some form of dysautonomia or issue with the baroreflex. This same maneuver may be performed to slow the heart rate when tachycardia is occurring.The test will need a device that is continually reading your heart rate such as an oximeter or smartwatch.