The Influence of Commonly-Encountered Participant Behaviors on Cardiovascular Indices during Testing.

Background: During laboratory testing, participants rest quietly in a supine posture with little movement. However, it is rather common for participants to display various behaviors. The extent to which these common encounters influence cardiovascular measures is unknown.

Methods: Fifty-five adults (36±15 years) were studied during the following seven randomized conditions in the supine position: 1) quiet stationary rest (control), 2) while drowsy, 3) while and 4) after talking to investigators, 5) while and 6) after cell phone use for texting, and 7) lying on the side.

Results: Heart rate was greater when the participants were talking to investigators (+4 mmHg) and texting on cell phones (+5 mmHg) compared with quiet rest. Systolic blood pressure (BP) increased by 4 mmHg and diastolic BP by 3 mmHg while talking to investigators. Systolic BP was 6 mmHg and diastolic BP was 5 mmHg lower in the 'side lying' position compared with quiet rest. In the side-lying condition, carotid-femoral pulse wave velocity (PWV) was not able to be measured in 38% (n=16) of the participants while brachial-ankle PWV was not affected. Brachial-ankle PWV was greater while (+65 cm/s) and after (+29 cm/s) the participants were talking to investigators whereas carotid-femoral PWV was not able to be measured during talking. The drowsy behavior did not influence any of the BP and PWV measures.

Conclusion: Talking during the testing period significantly increases all the cardiovascular measures but cell phone use prior to the measures does not appear to influence them.