ANAEROBIC THRESHOLD ALTERATIONS CAUSED BY ENDURANCE TRAINING IN MIDDLE-AGED MEN

Previously sedentary middle-aged males [9] underwent cycle endurance training 45 min/day for 9 wk with an average attendance of 4.1 days/wk. Seven males served as controls. Before and after the training period the subjects performed 3 cycle ergometer tests. Work rate was incremented by 15 W[Work]/min, to the subjects'' tolerance limit, in the first 2 tests; the 3rd test consisted of constant load cycling at an O2 uptake (.ovrhdot.VO2) just below the pretraining anaerobic threshold (AT). After training the AT increased significantly by 44%, expressed as absolute .ovrhdot.VO2, and by 15%, expressed relative to .ovrhdot.VO2 max [maximum .ovrhdot.VO2]. Significant increases were noted in .ovrhdot.VO2 max (25%), maximal minute ventilation (19%), and maximal work rate (28%). The test-retest correlation coefficients for the AT (%.ovrhdot.VO2 max) were 0.91 pre- and posttraining. Training did not alter steady-state .ovrhdot.VO2 during the submaximal exercise test; significant decreases occurred in CO2 output, .ovrhdot.VE [expiratory ventilation rate], respiratory quotient and .ovrhdot.VE/.ovrhdot.VO2. No changes occurred in the control subjects during this period. The AT was profoundly influenced by endurance training in previously sedentary middle-aged males.