Hypovolemic men and women regulate blood pressure differently following exposure to artificial gravity
| Autor: | Joyce M. Evans, Jon Rask, Fritz B Moore, Jorge M. Serrador, L. Christine Ribeiro, Charles F. Knapp, Qingguang Zhang, Nandu Goswami, Michael J. Falvo, Connor R. Ferguson, Jeffrey D. Smith, Vladimir Kostas, Siqi Wang, Michael B. Stenger |
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| Rok vydání: | 2015 |
| Předmět: |
Adult
Male Cardiac output Physiology medicine.medical_treatment Hypovolemia Orthostatic intolerance Blood Pressure Bed rest Orthostatic vital signs Sex Factors Physiology (medical) Heart rate medicine Humans Orthopedics and Sports Medicine Presyncope Weightlessness business.industry Public Health Environmental and Occupational Health General Medicine Stroke volume medicine.disease Blood pressure Anesthesia Orthostatic Intolerance Female business |
| Zdroj: | European Journal of Applied Physiology. 115:2631-2640 |
| ISSN: | 1439-6327 1439-6319 |
| Popis: | In addition to serious bone, vestibular, and muscle deterioration, space flight leads to cardiovascular dysfunction upon return to gravity. In seeking a countermeasure to space flight-induced orthostatic intolerance, we previ ously determined that exposure to artificial gravity (AG) training in a centrifuge improved orthostatic tolerance of ambulatory subjects. This protocol was more effective in men than women and more effective when subjects exercised. We now determine the orthostatic tolerance limit (OTL) of cardiovascularly deconditioned (furosemide) men and women on one day following 90 min of AG compared to a control day (90 min of head-down bed rest, HDBR). There were three major findings: a short bout of artificial gravity improved orthostatic tolerance of hypovolemic men (30 %) and women (22 %). Men and women demonstrated different mechanisms of cardiovascular regulation on AG and HDBR days; women maintained systolic blood pressure the same after HDBR and AG exposure while men’s systolic pressure dropped (11 ± 2.9 mmHg) after AG. Third, as presyncopal symptoms developed, men’s and women’s cardiac output and stroke volume dropped to the same level on both days, even though the OTL test lasted significantly longer on the AG day, indicating cardiac filling as a likely variable to trigger presyncope. (1) Even with gender differences, AG should be considered as a space flight countermeasure to be applied to astronauts before reentry into gravity, (2) men and women regulate blood pressure during an orthostatic stress differently following exposure to artificial gravity and (3) the trigger for presyncope may be cardiac filling. |
| Databáze: | OpenAIRE |
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