Parameters of heart rate variability during bicycle ergometry test

: Short-term (5 min) heart rate variability (HRV) was studied before and during submaximal bicycle exercise tests in 27 patients with ischemic heart disease, 23 patients with hypertension and 9 healthy subjects. Low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.40 Hz) power components of HRV were significantly decreased during submaximal exercise. The level of load at which abrupt decrease of low-frequency components below 40 ms(2) occurred possibly reflected individual exercise tolerance. Episodes of myocardial ischemia were associated with pronounced decreases of low - frequency HRV components.