Effects of physical training on ventilatory equivalent and respiratory exchange ratio during weight supported,steady-state exercise

Thirty-three college men participated in a 9-week endurance training program. An equal number of subjects served as controls. Pre- and post-test metabolic measurements were made during 10 min of submaximal exercise (1080 kpm/min at 60 rpm) and 15 min of recovery. Measurements included oxygen consumption, CO₂ production, ventilatory equivalent (V _E/VO₂ ratio) and respiratory exchange ratio (R). A three factor design variance analysis was used to analyze the effects of training on min-by-min exercise and recoveryV _E/VO₂ ratio andR. For the experimental group training resulted in a significant improvement in ventilatory efficiency during exercise, as well as a significant decrease inR. During recovery,V _E/VO₂ andR decreased significantly for both groups although the magnitude of change was greater for the group that trained. Apparently, there was a significant habituation effect due to test procedures for the control group. The results are discussed in terms of lactate production and substrate utilization during exercise.