Aviator medical certification involves evaluation of medical standards by an Aviation Medical Examiner (AME). To qualify for a first-class medical certificate, cardiovascular health of a pilot is assessed via electrocardiogram (ECG) allowing the AME to detect abnormalities (e.g., heart arrhythmias). Certification standards are made to ensure aviators are medically fit for duty and serve as a risk mitigation in the event of inauspicious conditions (e.g., hypoxia due to aircraft cabin decompression). Professional pilots served as test subjects (n=57) in a study involving simulated altitudes of sea level (21.0% O2) and 15,000 feet (11.2% O2) induced by an Environics, Inc. ROBD. Each subject experienced non-hypoxic and hypoxic exposures while performing three tasks (computerized neuropsychology tests-CFT/CS, computerized multi-tasking battery-MATB, and fixed-based flight simulation-SIM) each 10-minutes in duration. The occurrence of Premature Ventricular Contractions (PVCs) during hypoxia induction had a stronger association with the SIM task than with the MATB or CFT/CS. The results indicate that workload induced by stimulus tasks influences the occurrence of PVCs. Considerations for the compounding effects of workload and physiological stressors underscores the necessity of screening for abnormalities/pathology during aviator medical certification as a mitigation against PEs.