Abstract
PURPOSE: The aim of our study was to answer the following questions: (1) Is it possible to estimate the exercise training intensity according to heart rate in patients treated with beta-blockers after myocardial infarction? and (2) Are there any other appropriate alternate possibilities to estimate the training intensity?
METHODS: This study involved 112 men (60.2 +/- 8.6 years) with a previous myocardial infarction treated with beta-blockers. Patients underwent exercise echocardiography and also completed a symptom-limited cardiopulmonary ramp test to determine peak exercise capacity, maximal heart rate, heart rate (HR) at the anaerobic threshold (AT), peak oxygen uptake ([latin capital V with dot above]O2 peak) [latin capital V with dot above]O2consumption at AT, and exercise capacity at AT.
RESULTS: The mean value of HR at AT was 104.7 +/- 13.3 bpm, corresponding to 81.0% +/- 8% of [latin capital V with dot above]O2 peak and 87.9% +/- 5.6% of HRpeak. The mean HR at 80% HRpeak was 96 +/- 13.7 bpm, at 70% heart rate reserve (HRR) 103.3 +/- 13.1 bpm and at 80% HRR 108 +/- 14.4 bpm. A close correlation was observed between HR at AT and values at 80% HRpeak (r = 0.86, P < .01). A similar correlation was found also for 70% and 80% HRR (r = 0.87 and 0.88, respectively, P < .01). Exercise intensity at AT occurred close to the value of 1 W/kgbodyweight.
CONCLUSIONS: As an upper limit in determining training intensities, the assessment of AT is the gold standard. However, findings suggest that %HRpeak, %HRR, and %[latin capital V with dot above]O2 peak can be used alternatively. The use of workload expressed as in W/kg also appears useful.