Systems Physiology: Cardiopulmonary AGE ASSOCIATED DECLINES IN EXERCISE TIME TO EXHAUSTION AND VENTILATORY PARAMETERS IN TRAINED CYCLISTS

AGE ASSOCIATED DECLINES IN EXERCISE TIME TO EXHAUSTION AND VENTILATORY PARAMETERS IN TRAINED CYCLISTS. Frank B. Wyatt, Jason P. Mccarthy. JEPonline. 2002;6(1):1217. The purpose of this study was to investigate the cardiopulmonary parameters in a cross section of fit, aging cyclists to determine the associations between age, heart rate and ventilation on exercise time to exhaustion. Subjects were twenty-seven (N=27) males age 21 to 74 yrs. Each subject performed a maximal test on a cycle ergometer to volitional fatigue. Cardiopulmonary measures included; maximal oxygen consumption (VO2max, mL/kg/min, L/min), expired minute ventilation (VE, L/min), carbon dioxide production (VCO2, L/min), respiratory rate (RR) in breaths per minute (b/min), percent (%) O2 expired and % CO2 expired, ventilatory equivalents for O2 (VE/VO2) and CO2 (VE/VCO2), maximal heart rate (MHR, beats/min), ventilatory threshold (VT), heart rate threshold (HRT) and time to exhaustion (TE) in minutes (min). Through regression analyses with age as the independent variable, the following measures significantly declined with age: VO2, VE, VCO2, RR, MHR, VT, HRT and TE. Expired percent O2 and CO2, along with VE/VO2 and VE/VCO2 showed low coefficient values indicating little change between subjects with age. In conclusion, age decrements in cardiopulmonary related variables appear to be caused by diminished exercise capacities causing lowered maximal exercise intensities. The poor correlation between VE/VO2 and VE/VCO2 and age reveal that ventilatory capacities and function contribute little to the diminished exercise tolerance due to aging.