Different Orders of Upper- and Lower-Body Resistance Exercise on Heart Rate Variability in Women

Acute upper- or lower-body resistance exercise (RE) has been shown to induce similar impacts on autonomic modulation (AM). However, the effect on AM after different orders of combined upper- and lower-body RE are unclear. PURPOSE: To compare the different orders of upper-and lower-body RE on AM in young women. METHODS: Twenty-three young women (22±2 years old) completed the study. The upper- and lower-body RE (UL) condition consisted of latissimus dorsi pulldown, incline chest press, knee extension and knee flexion while the lower- and upper-body RE (LU) condition consisted of knee extension, knee flexion, latissimus dorsi pulldown, and incline chest press. AM was reported as natural logarithm (Ln), and included Root Mean Square Successive Difference (LnRMSSD), the proportion of NN50 divided by the total number of NN (R-R) intervals (LnPNN50), total power (LnTP), low frequency power (LnLF), and high frequency power (LnHF), and was assessed at rest, 15-20 (R1), and 25-30 (R2) minutes after either condition at 75% 1-repetition maximum for 3 sets of 10 repetitions with 1.5- and 2-minute rests between sets and exercises, respectively. A 2-way repeated measure ANOVA was used to determine the effect of different orders across time on AM. RESULTS: There was a significant (p=0.004) 2-way interaction for LnPNN50 (UL: Rest: 3.68±0.67, R1: 1.40±2.04, R2: 1.40±2.04; LU: Rest: 3.62±0.64, R1: 2.24±1.19, R2: 2.17±1.23) such that it increased in LU at R1 and R2 compared to UL. There were significant (p