A Simplified Approach for the Estimation of the Ventilatory Compensation Point

ONORATI, P., D. MARTOLINI, G. VALLI, P. LAVENEZIANA, P. MARINELLI, E. ANGELICI, and P. PALANGE. A Simplified Approach for the Estimation of the Ventilatory Compensation Point. Med. Sci. Sports Exerc., Vol. 44, No. 4, pp. 716-724, 2012. Incremental cardiopulmonary exercise test with gas exchange measurement is the gold standard for the identification of the ventilatory compensation point (VCP). It has previously been demonstrated that the change in the slope of increment of minute ventilation over HR (Delta V-E/Delta HR) can be used alternatively to the ventilatory equivalent for CO2 (Delta V-E/Delta CO2) method for detection of VCP in healthy subjects undergoing cycle ergometer (C) incremental exercise. The same evaluation during treadmill (T) incremental exercise and comparison between C and T have not yet been performed. Purpose: We analyzed, during both C and T incremental exercises, the V-E/HR and the respiratory rate (RR)/HR relationships, expressed either as slope or as an absolute value. We hypothesized that changes in the slope of increment of the two relationships could represent a reliable method for VCP detection, regardless of exercise mode and protocol. Methods: Fourteen healthy male subjects (age = 31 +/- 7 yr (mean +/- SD)) underwent two T incremental exercises-fast (F-T) and slow (S-T) protocols (8 km.h(-1), 2% (F-T) and 1% (S-T) grade per minute)-and one C incremental exercise (30 W.min(-1)). O-2 uptake (VO2), VCO2, V-E, HR, and RR were measured breath by breath. Results: A good between-method agreement in the detection of VCP by the Delta V-E/Delta CO2, Delta V-E/Delta HR, and the Delta RR/Delta HR slope changes was found in both T protocols and C. No differences (C vs T and F-T VS S-T) were found in the slope of the Delta V-E/Delta HR and Delta RR/Delta HR relationships after the VCP and in the Delta V-E/Delta HR and RR/HR absolute values at VCP. Conclusions: In healthy young males, the Delta V-E/Delta HR and Delta RR/Delta HR relationships during T and C incremental exercises can be reliably used to detect the VCP as an alternative to the ventilatory equivalent method.