Heart Rate Variability and Ventilatory Efficiency

The aims of this investigation were to identify possible associations between the resting high frequency component of heart rate variability and measures of ventilatory efficiency, determined during exercise, in a group of endurance trained athletes. V'E, V'CO2, and V'O-2 were measured during incremental exercise up to the anaerobic threshold (AT) and up to volitional exhaustion (V'O-2max) in 12 subjects. Resting high frequency heart rate variability (HFNU), determined using spectral analysis of ECG traces, was correlated with the V'E vs. V'CO2 slope calculated from data up to the AT, where a negative linear relation between the V'E vs. V'CO2 slope and HFNU was recorded (R-2 = 0.69). Also, resting HFNU Was correlated with the V'E vs. V'CO2 slope, when the data used for slope calculation included all V'E vs . V'CO2 data UP to V'O-2max (R-2 = 0.56). However, there was no evidence of association between the minimum V'E:V'CO2 and resting HFNU (R-2 = 0.08). Negative relations between V'E vs . V'CO2 slope and resting HFNU suggest that HFNU plays a role in matching blood flow in the lung to alveolar ventilation throughout the ventilatory cycle.