AIM: To evaluate the changes produced by maximal dynamic exercise in the rhythmic components of systolic arterial pressure variability. PATIENTS AND METHODS: We studied seven normotensive subjects during different levels of a modified treadmill test (Bruce protocol, up to stage 4). Arterial pressure was measured directly by a high-fidelity microtip pressure transducer. Spectral analysis provided two main oscillatory components of systolic arterial pressure variability, a low-frequency component related to the sympathetic-mediated neural control of vasomotion and a high-frequency component reflecting the mechanical effects of respiration on blood pressure. RESULTS: The low-frequency component increased at the beginning of exercise and remained stable thereafter, while the high-frequency component increased progressively. A third rhythmic component (very high frequency) with a frequency higher than respiration and synchronous with the rate of the subjects' footsteps, which was undetectable on a visual inspection of analog tracings, became progressively more apparent, reaching its maximum at exercise stage 4. CONCLUSIONS: These findings emphasize the importance of high-fidelity techniques and computer analysis for the evaluation of arterial pressure variability in dynamic conditions.
|Titolo:||Mechanical effects of respiration and stepping on systolic arterial pressure variability during treadmill exercise|
|Parole Chiave:||Exercise; High-fidelity arterial pressure; Spectral analysis|
|Settore Scientifico Disciplinare:||Settore MED/09 - Medicina Interna|
Settore MED/11 - Malattie dell'Apparato Cardiovascolare
Settore ING-INF/06 - Bioingegneria Elettronica e Informatica
|Data di pubblicazione:||1995|
|Appare nelle tipologie:||01 - Articolo su periodico|