Many of his field studies were conducted at Capanna Regina Margherita, a research station at the apex of Monte Rosa, Italy.
In 1902 with his assistant Hermann von Schrötter and meteorologists Arthur Berson and Reinhard Süring, he made two high-altitude balloon ascents in which they reached an altitude of 5000 meters.
In 1910 Zuntz participated in a scientific expedition to Pico de Teide in the Canary Islands with Schrötter and physiologists Arnold Durig (1872-1961) and Joseph Barcroft (1872-1947).
In 1885 with August Julius Geppert (1856-1937), he created the Zuntz-Geppert respiratory apparatus, and for field studies Zuntz invented a portable Gasuhr (dry gas measuring device).
In 1889 he constructed an early treadmill (Laufband), and in 1914 added an X-ray apparatus to the machine in order to observe cardiac changes during exercise.