CARDIORESPIRATORY AND SUBJECTIVE RESPONSES TO PROLONGED ARM AND LEG EXERCISE IN HEALTHY-YOUNG AND OLDER MEN

Ten young (aged 23-30 years) and nine older (aged 54-59 years) healthy men with a similar size of limb muscle mass performed arm crank and l eg cycle exercise for 30 min at relative exercise intensities of 50% a nd 75% of maximal oxygen uptake for the corresponding muscle group. In the tests, heart rate, blood pressure, gas exchange variables, rating of perceived exertion and blood lactate concentration were measured. The limb muscle mass was determined by anthropometric measurements. At the 75% target exercise level, four of the older men and two of the y oung men could not complete the arm-cranking test, and one of the olde r men and two of the young men could not complete the leg-cycle test. During arm-cranking the absolute exercise intensity was similar for th e young and older men because of similar maximal values during arm-cra nking. But during leg-cycling the absolute excercise intensity was hig her for the young men than for the older men due to the difference in corresponding maximal values. During arm-cranking there were no signif icant differences in the physiological responses between the age group s except that a higher ventilatory response was noted among the older compared to the young men. During leg-cycling the heart rate values we re higher among the young compared to the older men. But, when the hea rt rate values were expressed as a percentage of maximal heart rate in the corresponding maximal tests, no significant differences between t he age groups were found. The results indicated that 30-min of arm or leg exercise at the same relative submaximal excercise intensity produ ces a similar degree of physiological strain in healthy older compared to young men. During arm-cranking, the young and the older men exerci sed at the same external intensity, indicating a similar ability to pe rform prolonged exercise using smaller muscle groups expressed both in absolute and relative terms.