Cerebral vasoreactivity: impact of heat stress and lower body negative pressure
نویسندگان
چکیده
منابع مشابه
The effects of superimposed tilt and lower body negative pressure on anterior and posterior cerebral circulations
Steady-state tilt has no effect on cerebrovascular reactivity to increases in the partial pressure of end-tidal carbon dioxide (PETCO2). However, the anterior and posterior cerebral circulations may respond differently to a variety of stimuli that alter central blood volume, including lower body negative pressure (LBNP). Little is known about the superimposed effects of head-up tilt (HUT; decre...
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The process by which cerebral perfusion is maintained constant over a wide range of systemic pressures is known as "cerebral autoregulation." Effective dampening of flow against pressure changes occurs over periods as short as ~15 sec and becomes progressively greater over longer time periods. Thus, slower changes in blood pressure are effectively blunted and faster changes or fluctuations pass...
متن کاملLower body negative pressure exercise plus brief postexercise lower body negative pressure improve post-bed rest orthostatic tolerance.
Orthostatic intolerance follows actual weightlessness and weightlessness simulated by bed rest. Orthostasis immediately after acute exercise imposes greater cardiovascular stress than orthostasis without prior exercise. We hypothesized that 5 min/day of simulated orthostasis [supine lower body negative pressure (LBNP)] immediately following LBNP exercise maintains orthostatic tolerance during b...
متن کاملEffect of acute hypoxemia on cerebral blood flow velocity control during lower body negative pressure
The ability to maintain adequate cerebral blood flow and oxygenation determines tolerance to central hypovolemia. We tested the hypothesis that acute hypoxemia during simulated blood loss in humans would cause impairments in cerebral blood flow control. Ten healthy subjects (32 ± 6 years, BMI 27 ± 2 kg·m-2 ) were exposed to stepwise lower body negative pressure (LBNP, 5 min at 0, -15, -30, and ...
متن کاملMuscle sympathetic nerve activity during lower body negative pressure is accentuated in heat-stressed humans.
The purpose of this project was to test the hypothesis that increases in muscle sympathetic nerve activity (MSNA) during an orthostatic challenge is attenuated in heat-stressed individuals. To accomplish this objective, MSNA was measured during graded lower body negative pressure (LBNP) in nine subjects under normothermic and heat-stressed conditions. Progressive LBNP was applied at -3, -6, -9,...
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ژورنال
عنوان ژورنال: Clinical Autonomic Research
سال: 2014
ISSN: 0959-9851,1619-1560
DOI: 10.1007/s10286-014-0241-2