Loewy conducted extensive research in the field of altitude physiology.
This included studies performed at the Jüdischen Krankenhaus (Jewish Hospital) in Berlin, and at Capanna Regina Margherita, a research station at the top of Monte Rosa, Italy.
Here he worked with Dr. Zuntz, and other renowned scientists that included Angelo Mosso (1846-1910) and Arnold Durig (1872-1961).
With Austrian physiologist Hermann von Schrötter (1870-1928), he performed pioneer research of pulmonary hemodynamics.
In 1905, through the use of an endobronchial catheter, they were the first to achieve airway separation on a human subject.