Claus was born and raised in Germany. His diving career began in 1976 with training to become a rescue diver of the German Lifesaving Society. He is a certified Diving Instructor (CMAS****, ANDI Nitrox Instructor) with over 1800 logged dives. After graduating from Duesseldorf University he became a certified anaesthesiologist and specialist in intensive care and emergency medicine with diplomas in travel medicine of the German Society of Tropical medicine and in diving and hyperbaric medicine of the German Society of Diving and Hyperbaric Medicine.
His scientific career started in 1987 with research on nitrogen elimination after simulated scuba dives, which became his MD thesis and he cooperated with the German national aeronautics and space research centre where he was involved in research and manned very deep diving exploration beyond 700 msw. Later, he served as a Diving Medical Officer of the German Navy at the Naval Medical institute, where he had the chance to dive with the Navy SEAL Team and UDT divers. From 1997 to 2000 he was the head of the hyperbaric treatment facility of the University Hospital of Homburg and since 2000 he has worked in the Department of Anaesthesiology of the University Hospital of Ulm. Here, he continued his scientific work in the field of diving and hyperbaric medicine. His PhD thesis was on genotoxicity of hyperbaric oxygen. Claus has co-editor of five books on diving and travel medicine and intensive care medicine and published approximately 100 papers in scientific journals. He was awarded the Zetterström Award of the EUBS in 1999, the AGA Linde HBO-Award 2001 and, for his long-time dedication to in-water rescue, in 2004 the German President awarded him the Cross of the Order Merit of the Federal Republic of Germany. Today, he is Professor of Anaesthesiology and Head of the Division of Emergency Medicine of the Department of Anaesthesiology of the Hospital of Ulm, Ulm University of Medical School. In 2023 he additionally became the Founding Dean of Medical Faculty of the German University in Cairo (GUC), Egypt.