WISE 2005: stroke volume changes contribute to the pressor response during ischemic handgrip exercise in women
Autor: | Richard L. Hughson, P. Arbeille, P. Kerbeci, J. K. Shoemaker, L. Mattar, S. Trotter |
---|---|
Rok vydání: | 2007 |
Předmět: |
Adult
Cardiac output medicine.medical_specialty Sympathetic Nervous System Time Factors Physiology Physical exercise Blood Pressure Isometric exercise Forearm Heart Rate Ischemia Physiology (medical) Internal medicine Isometric Contraction Heart rate Reflex Supine Position Medicine Humans Splanchnic Circulation Muscle Skeletal Exercise Ultrasonography Blood Volume Muscle fatigue Hand Strength business.industry Portal Vein Stroke Volume Stroke volume Space Flight Femoral Artery medicine.anatomical_structure Muscle Fatigue Physical therapy Cardiology Vascular resistance Female Vascular Resistance business Blood Flow Velocity |
Zdroj: | Journal of applied physiology (Bethesda, Md. : 1985). 103(1) |
ISSN: | 8750-7587 |
Popis: | The mechanism of the pressor response to small muscle mass (e.g., forearm) exercise and during metaboreflex activation may include elevations in cardiac output (Q̇) or total peripheral resistance (TPR). Increases in Q̇ must be supported by reductions in visceral venous volume to sustain venous return as heart rate (HR) increases. Therefore, this study tested the hypothesis that increases in Q̇, supported by reductions in splanchnic volume (portal vein constriction), explain the pressor response during handgrip exercise and metaboreflex activation. Seventeen healthy women performed 2 min of static ischemic handgrip exercise and 2 min of postexercise circulatory occlusion (PECO) while HR, stroke volume and superficial femoral artery flow (Doppler), blood pressure (Finometer), portal vein diameter (ultrasound imaging), and muscle sympathetic nerve activity (MSNA; microneurography) were measured followed by the calculation of Q̇, TPR, and leg vascular resistance (LVR). Compared with baseline, mean arterial blood pressure (MAP) ( P < 0.001) and Q̇ ( P < 0.001) both increased in each minute of exercise accompanied by a ∼5% reduction in portal vein diameter ( P < 0.05). MAP remained elevated during PECO, whereas Q̇ decreased below exercise levels. MSNA was elevated above baseline during the second minute of exercise and through the PECO period ( P < 0.05). Neither TPR nor LVR was changed from baseline during exercise and PECO. The data indicate that the majority of the blood pressure response to isometric handgrip exercise in women was due to mobilization of central blood volume and elevated stroke volume and Q̇ rather than elevations in TVR or LVR resistance. |
Databáze: | OpenAIRE |
Externí odkaz: |