Hemodynamics of Seasonal Adaptation
| Autor: | Linda M. Lillis, Patricia S. Larrabee, Joseph L. Izzo, Etnilee Sander |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Adult
Male medicine.medical_specialty Cardiac output Adolescent Epinephrine Hemodynamics Blood Pressure Decreased cardiac output Supination Norepinephrine Heart Rate Internal medicine Heart rate Internal Medicine medicine Humans Cardiac Output Aged business.industry Stroke volume Middle Aged Adaptation Physiological medicine.anatomical_structure Blood pressure Vascular resistance Cardiology Female Seasons medicine.symptom business Vasoconstriction |
| Zdroj: | American Journal of Hypertension. 3:405-407 |
| ISSN: | 1941-7225 0895-7061 |
| DOI: | 10.1093/ajh/3.5.405 |
| Popis: | To investigate the possibility that seasonal adaptation requires significant hemodynamic changes, 5 normotensive and 21 mildly hypertensive subjects were followed through 4 seasons for changes in systemic hemodynamics and sympathetic nervous activity. In the upright position wintertime blood pressures increased by 3% (P = NS) over summer values whereas cardiac output and stroke volume decreased by 18% and 21%, respectively (P less than .0017 for each). Similarly, wintertime upright heart rate increased by 7% (P less than .017) with larger parallel increases in systemic vascular resistance (+24%, P less than .0017) and plasma norepinephrine (+26%, P less than .017). The supine values followed similar trends but the magnitude of changes was about 50% less than the corresponding upright values. Thus, in the northern US, wintertime vasoconstriction is related to increased sympathetic nervous activity and decreased cardiac output. When these reciprocal changes are proportional, blood pressure remains constant. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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