Ventilatory and Heart Rate Responses to Incremental Exercise With and Without Venous Occlusion

Godoy, Selena J., Master of Science, Biomedical Sciences, July 2003. Ventilatory and Heart Rate Responses to Incremental Exercise With and Without Venous Occlusion. 26 pp., 4 tables, 7 figures, 29 references. We sought to identify whether the accumulation of metabolites in exercising muscle was associated with the ventilator (VT) and heart rate thresholds (HRT). Subjects performed two incremental workload cycling exercise tests to maximal effort: 1) without intervention (CON) and 2) with leg venous occlusion cuffs inflated to 90 mmHg (CUF). Breath-by-breath measures of ventilation, expired respiratory gases and beat-to-beat heart rate were collected. VT and HRT were identified using mathematical techniques for detection of thresholds. The VO2 of the VT and HRT were not significantly different at p [less than] 0.05 and were strongly correlated in both CON (r=0.84) and CUF (r=0.83). These data suggest that the accumulation of intramuscular metabolites provides a stimulus to increase ventilation and heart rate.