The main objective of this study is to develop baseline "normal" reference values of both lung and heart function for healthy adults within the age range relevant to the United States Veteran population who served in the Southwest Asia theater of military operations.

This study will involve performing key components of the Department of Veterans Affairs the Airborne Hazards and Open Burn Pit Center of Excellence (AHOBPCE) and a VA network of Post-Deployment Cardiopulmonary Evaluation Network (PDCEN) Core Clinical Evaluation in asymptomatic unexposed healthy controls without known lung or heart disease to serve as a "normal" control comparator group for veterans evaluated by PDCEN.

This is an observational study to recruit and thoroughly characterize 200 age- and gender-matched healthy controls without a history of exposure to airborne hazards. The childhood health and disease profiles of participants will also be evaluated to provide assessment of their physical fitness as adolescents. The participants will undergo detailed clinical, physiological, and radiological evaluations that will match the PDCEN Core Clinical Evaluation, which includes administration of health, environmental and occupational exposures, respiratory, and physical fitness questionnaires, pulmonary function testing (PFT), forced oscillometry (FOT), cardiopulmonary exercise testing (CPET) with maximum effort, dynamic hyperinflation, and exercise-induced bronchospasm protocols, methacholine challenge testing, transthoracic echocardiography, and computer tomography (CT) of chest, as well as pulmonary and systemic biomarker analysis including fractional exhalation of nitric oxide (FeNO) and peripheral blood sampling for blood count and metabolic panel including liver and kidney function.

Inclusion Criteria:

• Age 24-68
• No respiratory complaints (defined as modified Medical Research Council score = 0)
• No use of respiratory medications

Exclusion Criteria:

• Non-English speaking

• Pregnancy

• BMI>35 Kg/m2

• Tobacco smoking within prior year

• Lifetime tobacco smoking of >5 pack-years

• Current inhaled cannabis use (any modality) >2x weekly

• Prior inhaled cannabis uses exceeding 2x weekly within the prior year

• Illicit drug use (other than cannabis)

• No prior or current major organ disease, including but not limited to:

  • Neuromuscular weakness

  • History of malignancy (other than non-melanoma skin cancer)-- HIV/AIDS

  • Autoimmune disease

  • Solid-organ or hematopoietic stem cell transplant

  • Cardiovascular disease (other than mild HTN; < 140/90; controlled on 2 or less medications)

    • Poorly-controlled HTN (SBP>140 or DBP>90 or use of more than 2 anti-hypertensive medications)
    • Any history of congestive heart failure (CHF, either HFpEF or HFrEF)
    • Any history of arrythmia (including atrial fibrillation)

Healthy "normal" adults within the age range relevant to the United States Veteran population who served in the Southwest Asia theater of military operations.