2.1. Participants

A total of 24 participants (15 males, 9 females) between the ages of 18 to 36 years old were recruited from the university campus community as volunteers to participate in this study (age: 22.38 ± 3.54 years; height: 172.21 ± 8.26 cm; body mass: 77.53 ± 17.22 kg). Eligibility criteria included anyone who was at least 18 years of age and willing to provide informed consent. Any individuals who were previously diagnosed with a cardiovascular disease or cardiac arrhythmia and/or were taking any medications influencing the cardiovascular system were excluded from this study. All study protocols for this study were approved by the Institutional Review Board (IRB) at the University of Massachusetts Lowell, and all participants provided written informed consent before data collection. This study was conducted in accordance with the Declaration of Helsinki. All participants were given opportunities to ask questions regarding the study before any data were collected.