Order Effects of Resistance and Stretching Exercises on Heart Rate Variability and Blood Pressure in Healthy Adults.

The purpose of this study was to compare the acute effect of different combinations and order of resistance exercise (RE) and stretching exercise (SE) on heart rate variability, systolic blood pressure (SBP), and diastolic blood pressure (DBP). Twenty subjects, recreationally trained, performed 5 sessions in a random order: (a) SE followed by RE no rest (SE + RE), (b) RE followed by SE no rest (RE + SE), (c) SE between RE sets (SBE), (d) SE isolated, and (e) RE isolated. Heart rate variability, SBP, and DBP were collected for 15 minutes before (baseline) and 60 minutes after each experimental session. A significant decrease was found for standardized deviation of differences between adjacent normal r-r intervals (RMSSDms) SE + RE (-50.79%), SE (+9.2%), SBE (-42.8%), and RE (-46.3%). Similarly, a significant increase was found for LFnu in SE + RE (+12.8%) and SBE (+16.6%). In addition, a significant decrease was found for HFnu in SE + RE (-34.8%) and SBE (-39.7%). Finally, a significant decrease was found for SBP in SE (-6.1%). In conclusion, this study indicated that SE followed by RE promotes a reduction in LFnu and RMSSDnu, with trivial to small magnitude decreases in SBP. Therefore, performing SE either before or between RE would be an important exercise prescription recommendation to lower cardiac load and consequently greater safety.