The Relationships between Using the Rating of Perceived Exertion, Metabolic Equivalent and Maximum Heart Rate at Ventilatory Threshold into Determine Appropriate Exercise Prescription for Intensity in Obese Diabetic Patients: A Preliminary Study

Background: The rating of perceived exertion (RPE), metabolic equivalent (MET) and maximum heart rate (HRmax) at ventilatory threshold (VT) are commonly used methods as physiological parameters for monitoring exercise intensity. However, the appropriate levels of training intensity for obese type 2 diabetic diabetes mellitus (type 2 DM) patients have not been established.Purpose: To examine the parameters in obese Type 2 DM patients at ventilatory threshold, the exercise capacity of obese Type 2 DM patients, and to determine the appropriate levels of exercise intensity for exercise prescription in obese type 2 DM patients was investigated.Methods: Twenty obese type 2 DM patients (body mass index ＞27) were recruited. The physiological parameters (maximum oxygen uptake, maximum heart rate [or simply HRmax], and RPE at ventilatory threshold) of these patients were measured and compared during the cardiopulmonary exercise test.Results: The mean age of the subjects was 54.3±10.9 years, and the mean body mass index was 30.3±3.7. There was no difference on gender, the maximum oxygen uptake, maximum heart rate, and RPE by gender effect (p＞0.05). At ventilatory threshold level, the mean metabolic equivalent was 4.1±0.9, and the mean RPE was 13.0±1.7. The mean heart rate at VT was 117.3±14.5 beats/min, which is corresponded to 70.6±8.3% of the age-predicted HRmax, and the heart rate reserve was 36.3±14.7%.Conclusion: Our results indicate that the appropriate levels of exercise intensity for obese type 2 DM patients are 70% of the age-predicted HRmax, 30-40% of the heart rate reserve, MET of 4, and RPE of 13.