Cerebral blood flow velocity during and after sustained isometric skeletal muscle contractions in man
| Autor: | V. I. Iyawe, F. Russo, M. B. Segal, F. J. Imms |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Adult
Male medicine.medical_specialty Adolescent Hemodynamics Physical exercise Isometric exercise Internal medicine medicine.artery Isometric Contraction Heart rate Supine Position Medicine Humans Hyperventilation Exercise physiology Muscle Skeletal Exercise business.industry Brain Ultrasonography Doppler General Medicine Blood Pressure Monitoring Ambulatory Cerebral Arteries Surgery medicine.anatomical_structure Cerebral blood flow Middle cerebral artery Vascular resistance Cardiology Female Vascular Resistance business Blood Flow Velocity |
| Zdroj: | Clinical science (London, England : 1979). 94(4) |
| ISSN: | 0143-5221 |
| Popis: | 1. Twenty-seven young subjects used their right hand to perform sustained, isometric contractions at 40% of maximum for 2 min while lying supine. 2. During the last 30 s of exercise, mean arterial blood pressure increased by 38 ± 4 mmHg (mean ± S.E.M.) and heart rate by 27 ± 2 beats/min. 3. Nineteen of the subjects respired eucapnically during exercise, increasing ventilation by 4.1 ± 0.5 litres/min. Eight subjects hyperventilated (7.1–19.6 litres/min) and decreased end-tidal Pco2 by 8.2 to 15.1 mmHg during the last minute of exercise. 4. In the eucapnic subjects mean flow velocity in the right (i.e. contralateral to the activated cortex) middle cerebral artery increased by 11.4 ± 1.0 cm/s, a change of 17%, during the contraction. This represents an increase in volume flow to the territory of this vessel, but an increase in global flow to the brain cannot be inferred. 5. In the eight subjects who hyperventilated during exercise, there was no rise of flow velocity in the middle cerebral artery, and in some subjects there was a fall during the first 2 min of recovery. These findings suggest that if subjects hyperventilate during handgrip exercise there could be a fall in volume flow to many regions of the brain during and after the exercise. |
| Databáze: | OpenAIRE |
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