Relationship between heart rate recovery and variabillity after treadmill exercise test / 中国基层医药

ABSTRACT

Objective To observe the relationship between short-term heart rate variability(HRV) and heart rate recovery (HRR) after exercise.Methods 495 patients (273 men),whose age ranged 19-85 years,were submitted to treadmill exercise tests and short-term HRV evaluations.The standard deviation of the normal-to-normal interval (SDNN),the square root of the mean squared differences of successive normal-to-normal intervals (RMSSD),the number of interval differences of successive normal-to-normal intervals greater than 50 ms (NN50 count),the proportion derived by dividing NN50 count by the total number of normal-to-normal intervals (pNN50) and frequency(lowfrequency power,high-frequency power,total power) domains were observed.Results Among 495 patients,106 patients(68 men) were elderly(age≥65 years).Male gender and hypertension were significantly higher in elderly patients.The young patients had higher HRR after exercise.HRR at 4min (54 ± 13) vs (60 ± 12) beats/min,P =0.003 was the most significant predictor for positive exercise test result.In the young group,both time domain measures (SDNN:correlation coefficient 0.34,P ＜ 0.001 ; RMSSD:correlation coefficient 0.37,P ＜ 0.001) and frequency domain measures (LF:correlation coefficient 0.21,P ＜ 0.001 ; HF:correlation coefficient 0.13,P =0.01 ; total power:correlation coefficient 0.22,P ＜ 0.001) were significantly associated with HRR at 4min.Conclusion HRR at 4min was significantly associated with short-term HRV of time and frequency domains in young individuals,but not elderly ones,who received treadmill exercise test.