Salivary Hormones, Cerebral Blood Flows, Respiratory Patterns and Cardiovascular Responses to Active Standing and Passive Head up Tilt
- Paper number
IAC-11,A1,3,12,x9475
- Author
Dr. Nandu Goswami, Medical Universitz of Graz, Austria
- Coauthor
Dr. Helmut Lackner, Medical Universitz of Graz, Austria
- Coauthor
Prof. Jean-Pierre Montani, University of Fribourg, Switzerland, Switzerland
- Coauthor
Prof. Helmut Hinghofer-Szalkay, Medical Universitz of Graz, Austria
- Year
2011
- Abstract
We investigated salivary cortisol (SC), alpha amylase (AA), cerebral blood flows (CBF), respiratory frequency (RF), end tidal CO2 concentration (EtCO2) and time course of hemodynamic changes (in 30 sec epochs) induced by active standing and 70º head up tilt (HUT). 14 healthy males underwent two randomized protocols: passive HUT and active standing, 2 weeks apart. HUT increased AA (+ 2.2±12 U/ml), heart rate (HR)(+19.2±7.0 bpm), mean arterial pressure (MAP)(+5.6±9.4 mmHg), diastolic blood pressure (DBP)(+6.7±8.9 mmHg), total peripheral resistance (TPR)(+179±257 dyne*s/cm5) and decreased SC (- 0.1±0.8 ng/ml), CBF (-4.6±5.6 cm/s), RF (-2.1±3.4 C/min), EtCO2 (-4.1±2.6 mmHg), stroke volume (SV)(-33.4±14.2 ml) and cardiac output (CO) (-0.7±1.2 l/min). Effects of standing and HUT induced cerebral blood flow, respiratory and hemodynamic responses were not different. Stressors, however, induced different initial heart rate, diastolic blood pressure and total peripheral resistance responses. Both stresses significantly affected initial HR changes. Similarly, when comparing different periods/phases of initial responses, significant differences were seen between HR, SV, CO, DBP and TPR. Overall, when comparing active and passive standing, initial responses of HR, DBP and TPR differed. Generally speaking, active standing is equally effective as the more complex HUT protocol in eliciting orthostatic neurohormonal and cerebral blood flow responses.
- Abstract document
- Manuscript document
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