Schack August Steenberg Krogh ForMemRS[1] (15 November 1874 – 13 September 1949) was a Danish professor at the department of zoophysiology at the University of Copenhagen from 1916 to 1945.

[5][6][7] In 1920 August Krogh was awarded the Nobel Prize in Physiology or Medicine for the discovery of the mechanism of regulation of the capillaries in skeletal muscle.

[8][9] Krogh was first to describe the adaptation of blood perfusion in muscle and other organs according to demands through opening and closing the arterioles and capillaries.

Later Krogh took on studies of water and electrolyte homeostasis of aquatic animals and he published the books: Osmotic Regulation (1939) and Comparative Physiology of Respiratory Mechanisms (1941).

He was a constructor of scientific instruments of which several had considerable practical importance, such as the spirometer and the apparatus for measuring basal metabolic rate.

[16] Krogh and his wife Marie, scientist in her own right, brought insulin to Denmark shortly after its discovery in 1922 by Frederick Banting and Charles Best.