Following graduation, he worked on his MD thesis entitled “Transthoracic Echocardiography in Pulmonary Hypertension” and gathered work experience in Zurich, at the University of Alabama at Birmingham and in Bavaria. His respiratory training led him to the Ruhrlandklinik at the University of Essen. He continued to follow his research interest in respiratory physiology and sleep-disordered breathing which brought him to London on a long-term research fellowship of the European Respiratory Society (ERS). His PhD thesis about "Sleep-Disordered Breathing and the Respiratory Muscles” at King’s College London resulted in significant research output with involvement in an impact case and the development of new intellectual property. His work within the field of respiratory and sleep physiology has evolved into research and academic collaborations across five continents. Professor Steier works as Consultant Respiratory Physician at the Lane Fox Unit, a tertiary service for weaning and non-invasive ventilation, and the British Sleep Society (BSS) accredited Sleep Disorders Centre at King’s Health Partners.