Paolo Cerretelli, an outstanding physiologist, scientific explorer and mentor to several generations of researchers, passed away on 20 February 2026 after a lifetime devoted to studying the limits of the human body under extreme conditions. He had been a Professor Emeritus of the Faculty of Medicine since his retirement in 1997.

Trained in Italy, Paolo Cerretelli embraced from an early stage the tradition of integrative physiology, combining experimental rigour with fieldwork. His academic career began at the University of Milan before bringing him to the UNIGE Faculty of Medicine in 1977, where he built over twenty years an internationally recognised research centre in the field of exercise and altitude physiology.

An expedition physician as early as 1959 in the Karakoram, and later scientific director of the Italian expedition on Everest in 1973, he turned these human adventures into open-air laboratories. There, he studied maximal oxygen uptake, ventilatory regulation, cardiac output and anaerobic metabolism in chronic hypoxia above 5,000 metres. His work on the limitations of performance at altitude, haematological adaptation and the "lactate paradox" — the finding that subjects acclimatised to high altitude paradoxically produce less lactate at maximal exercise, despite increasing tissue hypoxia — left a lasting mark on the field.

In Geneva, his research into the morphological and functional adaptation of skeletal muscle to prolonged hypoxia, conducted in collaboration with Swiss expeditions in the Himalayas, revealed the mitochondrial alterations and metabolic adaptation mechanisms induced by extreme altitude. He later embraced molecular and proteomic approaches, bridging classical integrative physiology with emerging concepts in hypoxic signalling.

He also studied Olympic athletes, hyperbaric chamber divers, astronauts in microgravity and, in Geneva, cardiac transplant recipients — a breadth of inquiry that reflects his constant concern to bring fundamental and clinical physiology into dialogue. His insatiable curiosity, methodological rigour and commitment to a whole-body vision of physiology left a profound mark on all those who worked with him. With Paolo Cerretelli passes one of the last representatives of a generation of physiologists for whom the mountain, the laboratory and the clinic were one and the same.