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 |
Autori: | |
Data di pubblicazione: | 1995 |
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Handle: | http://hdl.handle.net/11699/6228 |
Appare nelle tipologie: | 1.1 Articolo in rivista |