Ventilatory threshold and training heart rate in exercising cardiac patients

The purpose of this study was to determine the relationship between previously prescribed training heart rates (THR) for patients training for six months or more in a cardiac rehabilitation program (CRP), calculated Karvonen percentage heart rate reserve (THRk), and the ventilatory threshold (VT). In twenty male patients (ages 41-63) with documented coronary heart disease (CAD) [non-medicated] mean training heart rate (THR, 75% HRmax) was determined by a telemetry during training sessions. Incremental treadmill testing for determinations of the gas-exchange VT VOE vs. (VO2, Excess CO2) was performed, and the HR at the VT (VTHR) was determined. VO2max was 35.57 +/- 5.57 mL.kg-1.min-1; the VT, expressed as a percentage of VO2max, was 54.45%. The mean THR (133.8 +/- 13.4 bpm) and calculated THRk (141.1 +/- 9.74 bpm) were significantly greater (p less than .05) than the VTHR (124.8 +/- 15.5 bpm), indicating that VT occurs below intensities determined by other methods.