Article

Exercise training efficiently improves peak oxygen uptake
(V O2peak)
in patients with chronic heart failure. To optimize training-derived benefit,
higher exercise intensities are being explored. The correct identification of
anaerobic threshold is important to allow safe and effective exercise
prescription. DESIGN: During 48 cardiopulmonary exercise tests obtained in
patients with chronic heart failure (59.6 +/- 11 yrs; left ventricular ejection
fraction, 27.9% +/- 9%), ventilatory gas analysis findings and lactate
measurements were collected. Three technicians independently determined the
respiratory compensation point (RCP), the heart rate turning point (HRTP) and the
second lactate turning point (LTP2). Thereafter, exercise intensity (target heart
rate and workload) was calculated and compared between the three methods applied.
RESULTS: Patients had significantly reduced maximal exercise capacity (68% +/-
21% of predicted V O2peak) and chronotropic incompetence
(74% +/- 7% of predicted
peak heart rate). Heart rate, workload, and V O2 at HRTP and at RCP were not
different, but at LTP2, these parameters were significantly (P < 0.0001) higher.
Mean target heart rate and target workload calculated using the LTP2 were 5% and
12% higher compared with those calculated using HRTP and RCP, respectively. The
calculation of target heart rate based on LTP2 was 5% and 10% higher in 12 of 48
(25%) and 6 of 48 (12.5%) patients, respectively, compared with the other two
methods. CONCLUSIONS: In patients with chronic heart failure, RCP and HRTP,
determined during cardiopulmonary exercise tests, precede the occurrence of LTP2.
Target heart rates and workloads used to prescribe tailored exercise training in
patients with chronic heart failure based on LTP2 are significantly higher than those derived from HRTP and RCP.

Langue : ANGLAIS