The purpose of this study is to find out whether the COVID pandemic has affected participants' current physical activity, fitness, blood pressure, sleep, and mental stress to better understand its long-term health effects. To complete this study, participants will visit the Neurovascular Physiology Laboratory (NVPL) at the Indiana University School of Public Health Bloomington two times, requiring a total commitment of about 6 hours.

Visit 1 involves completing screening questionnaires, a consent document, and additional questionnaires about participant health behaviors (e.g., sleep and physical activity) and general mental and physical health. After the visit, participants will also start tracking their sleep and physical activity using wearable devices for 14 days, diet for at least 3 days, and blood pressure and urine for 24 hours.

Visit 2 is a second data collection visit, where participants will return the wearable devices. The investigators will measure participants' body composition, take measures of their cardiovascular health, and participants will complete a fitness test on a stationary cycle (exercise bike). The investigators will collect a 24 hour urine sample and take a blood sample to measure participants' blood glucose, electrolytes, hydration biomarkers, and markers of inflammation, as well as to study immune cells. The investigators will take participants' blood pressure at rest and during a hand-in-cold water test, which helps assess how participants' nervous system responds to stress. A full-body scan will measure participant body composition including bone density, muscle mass, and body fat percentage. Finally, participants will complete a cycling test that gradually increases in intensity to measure cardiovascular fitness.

Risks involve potential pain or bruising from blood draws, discomfort from blood pressure cuffs, stress from vigorous cycling, and psychological stress from questionnaires. There's also a slight risk of severe cardiovascular events occurring during exercise and loss of data confidentiality. Finally, the cold water test may result in a rare but noted situation where the body's nervous system overreacts to the cold stimulus, leading to a drop in blood pressure and heart rate. Participants will be monitored by trained staff during all procedures to ensure safety.

The investigator will be assessing whether prior severity of COVID-19 or (Post-acute Sequelae of SARS-CoV-2 Infection) PASC is associated with reduced physical activity and cardiorespiratory fitness, impaired blood pressure regulation, worse sleep, or heightened mental stress. Participants will report to the laboratory for two visits.

Visit 1 will be comprised of participant consent, screening, and completing questionnaires surrounding sleep, stress and mental health, food security, and habitual beverage intake. Visit 1 will take approximately 2 hours in total. Participants will be asked to read the consent form at this time and be encouraged to ask any questions. Participants can then: 1) sign the consent form; 2) take it home for further consideration; or 3) decide not to participate. Participants will be screened for eligibility once written informed consent has been given. At the conclusion of the first visit, participants will be given devices to track ambulatory blood pressure for 24 hours, physical activity and sleep for ~14 days, and diet for ≥3 days (i.e., 2 week days and 1 weekend day). 24 hours before the experimental visits, participants will be given a 24-hour urine collection container to measure urine volume, urine electrolyte concentrations, urine electrolyte excretion, and urine osmolality for eventual assessment of biomarkers of kidney function and kidney injury.

Visit 2 will be an experimental visit where each participant will undergo applied physiology measures, body composition, and exercise testing. During experimental visits, a blood draw will take place to assess changes in plasma electrolyte concentration, osmolality, hemoglobin, and hematocrit, and coded samples will be stored for future inflammation measures (e.g., CRP and IL-6) in addition to isolating peripheral blood mononuclear cells (PBMCs) for studying immune cell phenotype. Participants will then have rested BP assessed. Arterial stiffness will be measured using noninvasive tonometry techniques (Pulse Wave Analysis and Pulse Wave Velocity via SphygmoCor XCEL). We will use a hand-in cold-water test (described below) to assess sympathetic nervous system excitation. The cold pressor test is where participants will submerge their hand into an ice-cold bucket of water for three minutes to elicit a sympathetic nervous system stress response. Concurrently, BP reactivity will be assessed using a cold pressor test while participants engage in submaximal exercise on a stationary bicycle. Blood pressure reactivity will be measured at the finger using a finger-specific blood pressure cuff that will measure BP on a beat-to-beat basis. A total-body dual-energy X-ray absorptiometry (iDXA) scan will be used to assess bone mineral density, lean muscle mass, fat mass, and body fat percentage. Participants will finish the visit by completing a submaximal ramp cycling test on an electronically braked cycle ergometer to assess cardiovascular fitness. The test will begin at a low workload and increase incrementally every 30 minutes until the participant reaches 70% of their estimated maximal heart rate. Heart rate, workload, and perceived exertion will be recorded throughout to estimate cardiorespiratory fitness.

Collectively, these measures will enable the investigators to determine the study objectives pertaining to whether prior COVID-19 severity or PASC impacts cardiovascular health, which have important public health implications.

Inclusion Criteria:

Male and female participants. Are between the ages of 18-75. Have a resting blood pressure no higher than 150/90 (stage 2 hypertension). Have a BMI below 35 kg/m2 (otherwise healthy). Free from metabolic disease (diabetes or renal disease), pulmonary disorders (e.g., COPD, severe asthma, and cystic fibrosis), and cardiovascular disease (peripheral vascular, cardiac, or cerebrovascular).

Do not have any precluding medical issues that prevent participants from exercising (i.e., cardiovascular issues, or muscle/joint issues including painful arthritis) or giving blood (e.g., blood thinners).

Exclusion Criteria:

Younger than 18 or older than 30. Have a resting blood pressure > 150/90. Have a BMI > 35 Kg/m2 or < 18 Kg/m2. History of metabolic disease (diabetes or renal disease), pulmonary disorders (e.g., COPD, severe asthma, and cystic fibrosis), and cardiovascular disease (peripheral vascular, cardiac, or cerebrovascular).

Medical issues that prevent safe exercise (i.e., cardiovascular issues, or muscle/joint issues including painful arthritis).

Medical issues that prevent giving blood (e.g., blood thinners). Currently pregnant.

Younger than 18 or older than 75. Have a resting blood pressure > 150/90. Have a BMI > 35 Kg/m2 or < 18 Kg/m2. History of metabolic disease (diabetes or renal disease), pulmonary disorders (e.g., COPD, severe asthma, and cystic fibrosis), and cardiovascular disease (peripheral vascular, cardiac, or cerebrovascular).

Medical issues that prevent safe exercise (i.e., cardiovascular issues, or muscle/joint issues including painful arthritis).

Medical issues that prevent giving blood (e.g., blood thinners). Currently pregnant.

Unidentified individual participant data will be made available to other researchers upon reasonable request and data and material transfer agreement

2 years after completion of the study, indefinitely

Unidentified individual participant data will be made available to other researchers upon reasonable request and data and completion of a material transfer agreement with Indiana University.