| Autor: |
Tourula, Erica, Lenzini, Miramani, Rhodes, Addison, Hetz, Sarah E., Pearson, James |
| Předmět: |
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| Zdroj: |
American Journal of Physiology: Regulatory, Integrative & Comparative Physiology; Mar2024, Vol. 326 Issue 3, pR210-R219, 10p |
| Abstrakt: |
We investigated whether reducing face skin temperature alters arterial blood pressure control and lower body negative pressure (LBNP) tolerance after exercise heat stress. Eight subjects (1 female; age, 27 ± 9 yr) exercised at -63% V_ O2max until core temperature had increased ~1.5°C before undergoing LBNP to presyncope either with fanning to return face skin temperature to baseline (Δ-5°C, Fan trial) or without (No Fan trial). LBNP tolerance was quantified as cumulative stress index (CSI; mmHg·min). Before LBNP, whole body and face skin temperatures were elevated from baseline in both trials (38.0 ± 0.5°C and 36.3 ± 0.5°C, respectively, both P < 0.001). During LBNP, face skin temperature decreased in the Fan trial (30.9 ± 1.0°C) but was unchanged in the No Fan trial (36.1 ± 0.6°C, between trials P < 0.001). Mean arterial pressure was not different between trials (P = 0.237) and was similarly reduced at presyncope in both trials (from 82 ± 7 to 67 ± 8 mmHg, P < 0.001). During LBNP, heart rate was attenuated in the Fan trial at Mid LBNP (146 ± 16 vs. 158 ± 12 beats/min, P = 0.036) and at peak heart rate (158 ± 15 vs. 170 ± 15 beats/min; P < 0.001). LBNP tolerance was not different between trials (321 ± 248 vs. 328 ± 115 mmHg·min, P = 0.851). In exercise heatstressed individuals, lowering face skin temperature to normothermic values suppressed heart rate thereby altering cardiovascular control during a simulated hemorrhagic challenge without reducing tolerance. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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