Metabolic observations on Caucasian men and women aged 17 to 88 years.

Aerobic capacity (VO2 max) and body fat were measured indoors and VO2 was measured at about 36 to 42 degrees C in desert walks or runs in 69 adults aged 17 to 88 years. Eleven were athletic youths, and many of the older adults had participated in jogging programs. Body fat increased and VO2 max decreased with age, although there were notable exceptions. Rates of walking and running were planned to require about 40% of VO2 max. Midway in each walk VO2 (ml O2/horizontal m . kg) served as a measure of skill; skill was high in 10 of 11 youths who did many walks or runs. Each older adult did three walks; skill improved. In four groups with some persons aged 50 and older with body fat up to 40%, skill in their third walk matched that of youths. The least fit women and the least fit men did not attain that level of skill.