[Increased cortisol levels, frostbite and effects on the muscles and skeleton during extreme polar conditions].

Background: We wanted to record physiological changes, injuries and illnesses during a long sledge expedition in North Canada.

Material And Methods: The expedition consisted of four men aged 41 to 50, and 16 polar dogs. Measurements of cortisol in saliva were performed before, during and after the expedition. Frostbites and other injuries were registered continuously. Body weight and muscle, fat and bone mass were measured by dual X-ray absorptiometry scanning, and strength and endurance of shoulders, knees and back were tested. The group encountered extreme frost (-30 to -42 degrees C day temperature), wind, unexpected amounts of pack ice, and poorly motivated dogs.

Results And Interpretation: The participants showed increased free cortisol levels during their stay on the ice, probably because of increased mental stress. Three got first degree and two second-degree frostbites, but the affected areas were normal on vascular examination five months later. All members increased their muscle mass, but muscle strength and endurance remained unchanged.