Vascular Function and Oxidative Stress in Emergency Medical Responders

Inclusion Criteria: * Body mass index between 18.5 and \<35 kg/m² * Seated resting systolic blood pressure \< 140 mmHg, and seated resting diastolic blood pressure \< 90 mmHg * Participant must be an active first responder that works shift work schedules. e.g., emergency medical responders, basic life support emergency medical technicians (i.e., BLS EMT), advanced life support emergency medical technicians (A-EMT), and paramedics * Participant must have been working shift work for at least 1 year * Participant must work at least 4 night shifts per month Exclusion Criteria: * Participant is unwilling or unable to give consent * Participant has been diagnosed with any chronic disease (a history of high blood pressure, heart disease, diabetes, cancer, kidney disease) * Participant has been diagnosed with a sleep disorder (e.g., insomnia, restless leg syndrome, sleep apnea) * Participant is currently taking melatonin or other sleep aids (e.g., Ambien, sedatives, etc.), or any supplements/medications known to alter sleep patterns. Participants using melatonin must undergo a minimum 72-hour washout period prior to study participation to ensure baseline sleep patterns are not affected\[15, 16\] * Resting blood pressure \>140/90 mmHg * Body mass index \<18.5 or \>35 kg/m2 * Currently pregnant or breast feeding (women only) * Currently use tobacco or nicotine products (≥1 cigarette, cigar, e-cigarette, vape, or any other nicotine-containing product in the last month), including smokeless tobacco (e.g., chewing tobacco, snuff, dip, snus), nicotine lozenges or gum, heated tobacco products, and any illicit drugs