Influence of Commonly-Encountered Participant Behavior on Cardiovascular Measures during Physiological Testing

Abstract

Objective: When conducting laboratory testing, it is essential for participants to rest quietly in the supine posture without much movement. This is to establish a stable baseline to minimize external interference and distractions that could affect physiological measures. However, it is rather common that some participants start talking to investigators, fall asleep, or use cell phones for texting during the resting period. It is also common to observe some participants change their posture to side laying to make themselves more comfortable. The extent to which these common laboratory encounters influence cardiovascular outcome measures such as blood pressure and arterial stiffness has not yet been studied. Methods: A total of 55 adults (16 men and 39 women, 36±15 years) were studied under the following seven conditions: 1) quiet supine rest, 2) pretending to sleep, 3) while and 4) after talking to investigators, 5) during and 6) after cell phone use for texting, and 7) lying on the side. Each condition was separated by 5 minutes. The order of the conditions was randomized. Systolic and diastolic blood pressure (BP), heart rate, brachial-ankle pulse wave velocity (baPWV), and carotid-femoral PWV (cfPWV) were measured during these conditions. Results: Compared with quiet rest (61±10 bpm), heart rate was elevated (p<0.05) when the participants were talking to the investigators (65±10 bpm) and texting on cell phones (69±15 bpm). Both systolic and diastolic BP were 3-4 mmHg greater when they were talking to the investigators but 4-5 mmHg lower in the ‘side lying’ position compared with quiet rest. In the ‘side lying’ condition, baPWV was not affected but cfPWV was not able to be measured in 16 participants resulting in a 38% failure rate. baPWV was greater (p<0.01) while and after the participants were talking to investigators. cfPWV was not able to be measured during talking but was not affected when it was assessed after talking. Pretending to sleep and texting on a cell phone did not significantly influence any of the BP and PWV measures. Conclusions: Talking during the testing period significantly increases all the cardiovascular measures assessed in the present study. However, pretending to sleep and cell phone texting do not appear to influence them. There was no funding source for this study. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.