Effects of acute hyperthermia on the carotid baroreflex control of heart rate in humans
書誌事項
- 公開日
- 1997-06-09
- 権利情報
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- http://www.springer.com/tdm
- DOI
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- 10.1007/s004840050042
- 公開者
- Springer Science and Business Media LLC
この論文をさがす
説明
The purpose of this study was to examine the effect of hyperthermia on the carotid baroreceptor-cardiac reflexes in humans. Nine healthy males underwent acute hyperthermia (esophageal temperature -38.0 degrees C) produced by hot water-perfused suits. Beat-to-beat heart rate (HR) responses were determined during positive and negative R-were-triggered neck pressure steps from +40 to -65 mm Hg during normothermia and hyperthermia. The carotid baroreceptor-cardiac reflex sensitivity was evaluated from the maximum slope of the HR response to changes in carotid distending pressure. Buffering capacity of the HR response to carotid distending pressure was evaluated in % from a reference point calculated as (HR at 0 mm Hg neck pressure-minimum HR)/HR range x 100. An upward shift of the curve was evident in hyperthermia because HR increased from 57.7 +/- 2.4 beats/min in normothermia to 88.7 +/- 4.1 beats/min in hyperthermia (P < 0.05) without changes in mean arterial pressure. The maximum slope of the curve in hyperthermia was similar to that in normothermia. The reference point was increased (P < 0.05) during hyperthermia. These results suggest that the sensitivity of the carotid baroreflex of HR remains unchanged in hyperthermia. However, the capacity for tachycardia response to rapid onset of hypotension is reduced and the capacity for bradycardia response to sudden hypertension is increased during acute hyperthermia.
収録刊行物
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- International Journal of Biometeorology
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International Journal of Biometeorology 40 (4), 200-205, 1997-06-09
Springer Science and Business Media LLC