1. Human Physiology Laboratory, and Underwater and Hyperbaric Medicine Postgraduate Medical School, G. D'Annunzio University, School of Medicine, Chieti, Italy
2. Comsubin, Marina Militare, Le Grazie, Varignano, La Spezia, Italy
3. Department of Physiology, McGill University, 3655 Sir William Osler Promenade, Montreal, Quebec, Canada