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excessive polycythaemia hyperviscous blood
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Respir Physiol Neurobiol. 2007 May 18; [Epub ahead of print] Links
Cardiovascular adjustments for life at high altitude.Hainsworth R,
Drinkhill MJ.
Institute for Cardiovascular Research, University of Leeds, Leeds LS2
9JT, UK.
The effects of hypobaric hypoxia in visitors depend not only on the
actual elevation but also on the rate of ascent. There are increases
in sympathetic activity resulting in increases in systemic vascular
resistance, blood pressure and heart rate. Pulmonary vasoconstriction
leads to pulmonary hypertension, particularly during exercise. The
sympathetic excitation results from hypoxia, partly through
chemoreceptor reflexes and partly through altered baroreceptor
function. Systemic vasoconstriction may also occur as a reflex
response to the high pulmonary arterial pressures. Many communities
live permanently at high altitude and most dwellers show excellent
adaptation although there are differences between populations in the
extent of the ventilatory drive and the erythropoiesis. Despite living
all their lives at altitude, some dwellers, particularly Andeans, may
develop a maladaptation syndrome known as chronic mountain sickness.
The most prominent characteristic of this is excessive polycythaemia,
the cause of which has been attributed to peripheral chemoreceptor
dysfunction. The hyperviscous blood leads to pulmonary hypertension,
symptoms of cerebral hypoperfusion, and eventually right heart failure
and death.
PMID: 17597013 [PubMed - as supplied by publisher]
excessive polycythaemia hyperviscous blood
<<snip>> <<snip>>
Respir Physiol Neurobiol. 2007 May 18; [Epub ahead of print] Links
Cardiovascular adjustments for life at high altitude.Hainsworth R,
Drinkhill MJ.
Institute for Cardiovascular Research, University of Leeds, Leeds LS2
9JT, UK.
The effects of hypobaric hypoxia in visitors depend not only on the
actual elevation but also on the rate of ascent. There are increases
in sympathetic activity resulting in increases in systemic vascular
resistance, blood pressure and heart rate. Pulmonary vasoconstriction
leads to pulmonary hypertension, particularly during exercise. The
sympathetic excitation results from hypoxia, partly through
chemoreceptor reflexes and partly through altered baroreceptor
function. Systemic vasoconstriction may also occur as a reflex
response to the high pulmonary arterial pressures. Many communities
live permanently at high altitude and most dwellers show excellent
adaptation although there are differences between populations in the
extent of the ventilatory drive and the erythropoiesis. Despite living
all their lives at altitude, some dwellers, particularly Andeans, may
develop a maladaptation syndrome known as chronic mountain sickness.
The most prominent characteristic of this is excessive polycythaemia,
the cause of which has been attributed to peripheral chemoreceptor
dysfunction. The hyperviscous blood leads to pulmonary hypertension,
symptoms of cerebral hypoperfusion, and eventually right heart failure
and death.
PMID: 17597013 [PubMed - as supplied by publisher]
