Effect of static and dynamic exercise on heart rate and blood pressure variabilities

Purpose: This study examines the effect of static and dynamic leg exercises on heart rate variability (HRV) and blood pressure variability (BPV) in hu mans. Methods: 10 healthy male subjects were studied at rest, during static exercise performed at 30% of maximal voluntary contraction (SX30), and dur ing dynamic cycling exercises done at 30% of (V) over dot O-2max (DX30) and at 60% of (V) over dot O-2max (DX60). Respiration, heart rate, and blood p ressure signals were digitized to analyze temporal and spectral parameters involving short and overall indexes (SD, Delta RANGE, RMSSD, Total power), power of the low (LF), middle (MF), and high (HF) frequency components, and the baroreceptor sensitivity by the alpha(MF) index. Results: During SX30, indexes of HRV as SD, Delta RANGE, Total power, and MF in absolute units i ncreased in relation with rest values and were significantly higher (P < 0. 001) than during DX30 and DX60; HF during SX30, in normalized and absolute units, was not different of the rest condition but was higher (P < 0.001) t han HF during DX30 and DX60. Parameters of BPV as SD and Delta RANGE increa sed (P < 0.001) during both type of exercises, and significant (P < 0.01) i ncrements were observed on MF during SX30 and DX30; systolic HF was attenua ted during DX30 (P < 0.05), whereas diastolic HF was augmented during DX60 (P < 0.001). Compared with rest condition, the alpha(MF) index decreased (P < 0.01) only during dynamic exercises. Conclusion: Because HRV and BPV res ponse is different when induced by static or dynamic exercise, differences in the autonomic activity can be advised. Instead of the vagal withdrawal a nd sympathetic augmentation observed during dynamic exercise, the increase in the overall HRV and the MF component during static exercise suggest an i ncreased activity of both autonomic branches.