Aims: This study was done to evaluate the effect of three kinds of respiratory protective equipments (RPE) on the heart rate in light, moderate and heavy workload. Materials and Methods: This study was performed on eleven healthy university students (male) under controlled thermal conditions in a climatic chamber. The mean (SD) of age, height and body mass index (BMI) were 24.1 (2.34) years, 172 (4.2) cm and 22.4 (1.1) Kg/m2, respectively. Subjects were participated in the four intermittent exercises experiments (without RPE, valve, half-face and full-face) on a treadmill in light, moderate and heavy workload. Duration of light, moderate and heavy activities was 30, 30 and 20 min, respectively. Heart rate was recorded every 5 min. Results: The mean of heart rate in 11 subjects for without RPE trial in light, moderate and high workload was 93.5±13.1, 109.7±18.1 and 119.6±25.8 beats per min (bpm), for valve RPE was 102.8±9.7, 116.7±16.0 and 132.1±23.2 bpm, for half-face RPE was 102.4±11.42, 117.3±15.8 and 132.0±23.1 bpm and for full-face RPE was 109.3±14.7, 125±17.4 and 140.1±23.1 bpm, respectively. In three work load, significant differences between the mean of heart rate by using three kinds of RPE trials showed with without RPE trial were observed (P-value < 0.001). Also, mean of heart rate in three workload levels when using full-face RPE trial was significantly higher than valve and half-face RPE trials. In the valve and half-face RPE trials, significant differences were not detected Conclusions: The results demonstrated that heart rate were significantly increased with wearing of three kinds of RPE. Full-face RPE have a higher effect on increasing heart rate than half-face RPE.