This paper presents the results of a study of three methods for estimating the respiratory wave (RW) and respiratory rate (RR) using the electrocardiogram (ECG). There were applied methods from different groups: amplitude modulation ECG-Derived Respiration (EDR), frequency modulation Respiratory Sinus Arrhythmia (RSA) and Baseline Wander (BW) processing with the Savitzky–Golay filter (S–G). The theoretical aspects of the methods were presented in the Part 1 of the publication which was entitled: “Three Methods for the Determination of the Respiratory Waves from ECG Part I”. RR parameter estimation was performed for all the three methods for 12 subjects. The research concerning the influence of the parameters: Body Mass Index (BMI), Tidal Volume (TV) -, Forced Expiratory Volume in 1 second (FEV1) and – Forced Vital Capacity (FVC) on the errors of the estimated parameter RR. Moreover, all 12 signals, which were acquired with the help of a 12-lead Holter ECG were taken into consideration. The results indicate a preliminary dependence of respiratory parameters and BMI on the Respiratory Wave and, further, on the RR estimation errors. Consequently, the type of method and ECG Holter leads depend on the BMI and respiratory parameters. Studies with larger numbers of objects to definitively confirm these relationships are planned. In addition, an optimal selection of S–G filter parameters was carried out. Finally, a proprietary reference embedded system for recording RW and calculating RR was demonstrated.