Work tolerance: age and altitude

Abstract

The work capacity at sea level and high altitude has been measured on nine men, five of whom had taken part in similar studies at high altitudes from 18 to 33 years earlier. Except for a few measurements on the treadmill at sea level each subject rode the bicycle ergometer; the brakeload was increased minute-by-minute until his limit was reached. The maximum capacity for oxygen intake declined with age both at high altitude and at sea level. Individual responses varied greatly: the most fit individual, age 54, had about as great an oxygen intake on the ergometer at Pb 455 mm Hg as had a man one-half his age at sea level. After 5 or 6 weeks of acclimatization a man of 71 attained at Pb 485 a greater oxygen intake per minute and per kilogram than that of a man of 27. At that barometric pressure the limiting oxygen intake on the bicycle ergometer may be only one-half of the sea-level value 2 or 3 days after arrival; after 4–6 weeks it may range from two-thirds to five-sixths of the sea-level value. adaptation to altitude; altitude and heart rate; altitude and maximum O2 intake; altitude and respiratory volume Submitted on November 4, 1963