Problem statement: Living in high altitude areas results in chronic hypoxia, which induces complex metabolic and endocrine adaptations. The current study investigated the endocrine responses of male Westar rats chronically exposed to high altitude-induced hypoxia in Abha City, in Southwestern Saudi Arabia. Approach: The rats were separated in to 2 groups of 10 rats. The first group was kept at ...

Medical congresses often held in highlands. We reviewed several medical issues associated with altitude stress especially while physicians have participated medical congress held in high altitude. Altitude stress, also known as an acute mountain sickness (AMS), is caused by acute exposure to low oxygen level at high altitude which is defined as elevations at or above 1,200 m and AMS commonly oc...

Vascularity is increased in placentas from high- compared with low-altitude pregnancies. An angiogenic response to hypoxia may protect an organ from further hypoxic insult by increasing blood flow and oxygen delivery to the tissue. We hypothesized that increased placental vascularity is sufficient to adapt to high altitude. Therefore, indexes of hypoxic stress would not be present in placentas ...

• Outline the effects of increasingly higher altitudes on (1) partial pressure of oxygen in ambient air, (2) oxygen saturation of hemoglobin in pulmonary capillaries, and (3) V O2max • Describe and quantify the oxygen transport cascade at sea level and at 4300 m • Discuss immediate and longer-term physiologic adjustments to altitude exposure • Give symptoms, possible causes, and treatment for a...

A primary goal of molecular ecology is to understand the influence of abiotic factors on the spatial distribution of genetic variation. Features including altitudinal clines, topography and landscape characteristics affect the proportion of suitable habitat, influence dispersal patterns, and ultimately structure genetic differentiation among populations. We studied the effects of altitude and t...

Exposure to chronic hypoxia during gestation predisposes infants to neonatal pulmonary hypertension, but the underlying mechanisms remain unclear. Here, we test the hypothesis that moderate continuous hypoxia during gestation causes changes in the rho-kinase pathway that persist in the newborn period, altering vessel tone and responsiveness. Lambs kept at 3,801 m above sea level during gestatio...

Fluctuations in autonomic cardiovascular regulation during exposure to high altitude may increase the risk of heart attack during waking and sleep. This study compared heart rate variability (HVR) and its components during sleep at low altitude and after 30 41 hours of acclimatization at high altitude (3480 m) in five mountain marathon runners controlled for diet, drugs, light-dark cycle and je...

Acute mountain sickness is the commonest acute high altitude illness occurring at high altitude. Its prevalence is dependent on the ascent rate, altitude achieved, physical effort required to reach the target altitude and pharmacological intervention undertaken by the tourists visiting high altitude areas. This Letter to the Editor is an endeavour to re-emphasise the importance of all these fac...

BACKGROUND AND PURPOSE Andean highlanders, unlike Ethiopians, develop chronic mountain sickness (CMS), a maladaptation to their native land. Ambient hypoxia induces NO-mediated vasodilatation. Fitness for life at altitude might be revealed by cerebrovascular responses to NO. METHODS Nine altitude-native men were examined at 3622 and 794 m in Ethiopia and compared with 9 altitude-native Andean...

Effects of high altitude hypoxia on systolic time intervals were examined in 34 healthy men: 20 sea level residents studied at rest and at the end of 3 minutes steady isometric (handgrip) exercise at sea level and then serially for the first 5 days and on the tenth day, at an altitude of 3658 m, and I4 permanent residents at high altitude studied at high altitude. In the sea level residents the...