Consistency between the Standardized Methods of Exercise Prescription and the Target Heart Rate for the Cardiopulmonary Exercise Test in Individuals with Metabolic Syndrome

Purpose This study aimed to compare differences and consistencies between the target heart rate (THR) for aerobic exercise based on the standardized physiological maximum value percentage and the first-ventilatory-threshold heart rate (HR _VT1 ). The maximum physiological value percentage with the highest consistency with HR _VT1 , combined with the maximum heart rate (HR _max ) prediction equation, can guide safe and effective exercise in patients with metabolic syndrome (MetS) in practical applications. Methods Three HR _max prediction equations were used to calculate the THR as 35%, 45% and 50% heart rate reserve (HRR) and 55%, 60% and 65% HR _max, and the results were compared for correlation and consistency with HR _VT1 . HR _VT1 was measured through a cardiopulmonary exercise test (CPET) that complied with current guidelines and laboratory standards. Results According to the Fox equation, the difference in HR _VT1 and 35% HRR was not statistically significant (P = 0.060). Bland‒Altman analysis indicated that the mean difference in HR _VT1 and 35% HRR was − 0.350, which was close to the 0 line, and 95.83% of the patients (46/48) had values within the 95% limits of agreement. The absolute maximum difference within the limits of agreement was 7.90, the interclass correlation coefficient (ICC) was 0.862 (P < 0.001), and the 95% confidence interval was 0.767–0.920, indicating high consistency and good accuracy. Conclusion Among Chinese MetS patients, 35% HRR determined via the standardized HRR method and the acquired CPET VT1 had high consistency. Especially when applying the Fox equation, the exercise intensity of MetS patients can be best kept within the moderate-intensity domain near VT1.