Introduction: During the COVID-19 pandemic, health care workers (HCWs) experienced increased anxiety, depression, loneliness, and other mental health issues. HCWs need additional resources to cope with the mental health impact of their work. Yoga techniques could be helpful strategies to manage different stressors during times of uncertainty. Methods: This prospective, single-arm, trial examined the effects of a brief pranayama yoga practice on the wellbeing of HCWs during the height of COVID-19. HCWs were recruited through announcements and institutional websites at a large major cancer center in the southern United States. A short, prerecorded, 5-min breathwork video intervention called "Simha Kriya" was provided to participants, and they were encouraged to practice one to two times daily for 4 weeks. Participants completed self-report instruments at baseline and weeks 1 and 4, including: (1) Perceived Stress Scale (PSS); (2) Brief Resilient Coping Scale (BRCS); and (3) a questionnaire assessing the experience of COVID-19 among HCWs that had five subscales. HCWs also conducted a measure of breath holding time. Paired sample t-tests and mixed-effects analysis of variance models examined changes over time. Results: One hundred participants consented to the study, with 88 female, 60 white, 39 worked remotely, and 27 were clinical staff. Sixty-nine participants provided data at week 1 and 56 at week 4. Participants' adherence to the breathing exercises between weeks 1 and 4 was similar, with a mean of six times per week. At week 4, there were significant decreases in the COVID-19 Distress score (p < 0.0001) and COVID-19 Disruption (p = 0.013), yet no changes in the PSS. There were also significant increases in COVID-19 Stress Management (p = 0.0001) and BRCS scores (p = 0.012), but no changes in Perceived Benefits of COVID-19 and no changes in breath holding time. Discussion: Brief yoga-based breathing practices helped reduce pandemic-specific stress, improved resilience, and stress management skills in HCWs. Trial Registration Number: NCT04482647.