Altitude acclimatization and deterioration

2012 ◽  
pp. 67-78
Keyword(s):  
Altitude Acclimatization

Altitude acclimatization: plasma AVP response and physiological changes

2013 ◽  
pp. 1-1
Author(s):  
Meenakshi Sachidhanandam ◽  
Salthan Ashok Kumar ◽  
Som Nath Singh ◽  
UdaySankar Ray
Keyword(s):  
Physiological Changes ◽  
Altitude Acclimatization

Relative Significance of Specific Pulmonary Adaptations to Altitude Acclimatization

CHEST Journal ◽  
1972 ◽  
Vol 61 (2) ◽  
pp. 51S-53S
Author(s):  
J.A. Dempsey ◽  
W.G. Reddan ◽  
M.L. Birnbaum ◽  
H.V. Forester ◽  
J. Thoden ◽  
...  
Keyword(s):  
Relative Significance ◽  
Altitude Acclimatization

Changes in alveolar and arterial gas tensions as related to altitude and age

1964 ◽  
Vol 19 (1) ◽  
pp. 21-24 ◽  
Author(s):  
James W. Terman ◽  
Jerry L. Newton
Keyword(s):  
High Altitude ◽  
Pulmonary Ventilation ◽  
Research Station ◽  
Age Changes ◽  
Altitude Acclimatization ◽  
Ventilation Perfusion Ratio ◽  
Early Phases ◽  
Chilean Andes

In the summer of 1962 at the White Mountain Research Station the early phases of altitude acclimatization were studied in six of the surviving eight members of the 1935 expedition to the Chilean Andes; they were from 58 to 71 years of age. Alveolar and arterial Po2 and Pco2 were determined for each man a few hours after arrival at 3,093 m and at 3,800 and 4,343 m over the next few days. The effects of age were superimposed on the classical responses to high altitude. The arterial and alveolar Pco2 values showed no significant gradient; the alveolar Pco2 was found to be lower for a given altitude than 27 years before. For example, their average alveolar Pco2 at 4,700 m in 1935 was 27.7 mm Hg as opposed to 25.1 mm Hg at 4,343 m in 1962. The case of Hall was exceptional: his alveolar Pco2 ranged from 21 to 24 mm Hg regardless of altitude for his sojourn of 22 days. In 1935 these six men had a mean A-a Po2 gradient of +3.0 mm Hg at 4,700 m, while in 1962 the gradient over the three altitudes was +12.4 mm Hg. These findings would likely be explained partially by age changes in the pulmonary ventilation-perfusion ratio. acclimatization; pulmonary ventilation-perfusion ratio; alveolar-arterial Po2 and Pco2 gradients; alveolar hyperventilation; aging and altitude Submitted on February 19, 1963

Acclimatization to 4,300-m altitude decreases reliance on fat as a substrate

1996 ◽  
Vol 81 (4) ◽  
pp. 1762-1771 ◽  
Author(s):  
A. C. Roberts ◽  
G. E. Butterfield ◽  
A. Cymerman ◽  
J. T. Reeves ◽  
E. E. Wolfel ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Hypobaric Hypoxia ◽  
Barometric Pressure ◽  
Cycle Ergometry ◽  
Glycerol Release ◽  
Altitude Acclimatization ◽  
Altitude Exposure ◽  
Consumption Rates ◽  
Uptake And Release ◽  
Rest And Exercise

Roberts, A. C., G. E. Butterfield, A. Cymerman, J. T. Reeves, E. E. Wolfel, and G. A. Brooks. Acclimatization to 4,300-m altitude decreases reliance on fat as a substrate. J. Appl. Physiol. 81(4): 1762–1771, 1996.—We tested the hypothesis that exposure to altitude decreases reliance on free fatty acids (FFA) as substrates and increases dependency on blood glucose. Therefore, the effects of exercise, hypobaric hypoxia, and altitude acclimatization on FFA, glycerol and net glucose uptake and release [ = 2(leg blood flow)(arteriovenous concentration)] and on fatty acid (FA) consumption by the legs (= 3 × glycerol release + FFA uptake) were measured. Because sympathetic responses have been implicated, we utilized nonspecific β-blockade and observed responses to exercise, altitude, and altitude acclimatization. We studied six healthy β-blocked men (β) and five matched controls (C) during rest and cycle ergometry exercise (88 W) at 49% of sea-level (SL) peak O2 uptake at the same absolute power output on acute altitude exposure (A1; barometric pressure = 430 Torr) and after 3 wk of chronic altitude exposure to 4,300 m (A2). During exercise at SL, FA consumption rates increased ( P < 0.05). On arrival at 4,300 m, resting leg FFA uptake and FA consumption rates were not significantly different from those at SL. However, after acclimatization to altitude, at rest leg FA consumption decreased to essentially zero in both C and β groups. During exercise at altitude after acclimatization, leg FA consumption increased significantly, but values were less than at SL or A1 ( P < 0.05), whereas glucose uptake increased relative to SL values. Furthermore, β-blockade significantly increased glucose uptake relative to control. We conclude that 1) chronic altitude exposure decreases leg FA consumption during rest and exercise; 2) relative to SL, FFA uptake decreases while glucose uptake increases during exercise at altitude; and 3) β-blockade potentiates these effects.

Altitude acclimatization attenuates plasma ammonia accumulation during submaximal exercise

1987 ◽  
Vol 63 (2) ◽  
pp. 758-764 ◽  
Author(s):  
P. M. Young ◽  
P. B. Rock ◽  
C. S. Fulco ◽  
L. A. Trad ◽  
V. A. Forte ◽  
...  
Keyword(s):  
Sea Level ◽  
Endurance Performance ◽  
Ammonia Concentration ◽  
Submaximal Exercise ◽  
Active Group ◽  
Cycle Exercise ◽  
Plasma Ammonia ◽  
Altitude Acclimatization ◽  
Ammonia Accumulation ◽  
Sedentary Group

This study examined the effects of acclimatization to 4,300 m altitude on changes in plasma ammonia concentrations with 30 min of submaximal [75% maximal O2 uptake (VO2max)] cycle exercise. Human test subjects were divided into a sedentary (n = 6) and active group (n = 5). Maximal uptake (VO2max) was determined at sea level and at high altitude (HA; 4,300 m) after acute (t less than 24 h) and chronic (t = 13 days) exposure. The VO2max of both groups decreased 32% with acute HA when compared with sea level. In the sedentary group, VO2max decreased an additional 16% after 13 days of continuous residence at 4,300 m, whereas VO2max in the active group showed no further change. In both sedentary and active subjects, plasma ammonia concentrations were increased (P less than 0.05) over resting levels immediately after submaximal exercise at sea level as well as during acute HA exposure. With chronic HA exposure, the active group showed no increase in plasma ammonia immediately after submaximal exercise, whereas the postexercise ammonia in the sedentary group was elevated but to a lesser extent than at sea level or with acute HA exposure. Thus postexercise plasma ammonia concentration was decreased with altitude acclimatization when compared with ammonia concentrations following exercise performed at the same relative intensity at sea level or acute HA. This decrease in ammonia accumulation may contribute to enhanced endurance performance and altered substrate utilization with exercise following acclimatization to altitude.

Red blood cell senescence and neocytolysis in humans after high altitude acclimatization

2007 ◽  
Vol 38 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Angela Risso ◽  
Marina Turello ◽  
Franco Biffoni ◽  
Guglielmo Antonutto
Keyword(s):  
Blood Cell ◽  
High Altitude ◽  
Red Blood Cell ◽  
Cell Senescence ◽  
Altitude Acclimatization ◽  
High Altitude Acclimatization

Effects of altitude acclimatization and deacclimatization on bone and marrow volume in dog

1965 ◽  
Vol 209 (2) ◽  
pp. 347-352 ◽  
Author(s):  
Joseph K. Gong
Keyword(s):  
Sea Level ◽  
Relative Distribution ◽  
Level Control ◽  
Marrow Fat ◽  
Cortical Volume ◽  
Altitude Acclimatization ◽  
The Individual ◽  
And Sea Level

Skeletons of altitude-acclimatized, altitude-deacclimatized, and sea-level control dogs were completely analyzed for water, fat, and nonfatty organic and inorganic fractions. The total skeletal and marrow volumes as well as their contents were calculated and compared. Neither the marrow volume nor the bone (trabecular and cortical) volume was affected by the altitude changes. The relative distribution of marrow and bone in the various parts of the skeleton was also unchanged. Marrow fat in the whole skeleton as well as in the individual parts of the skeleton was lowered on acclimatization and increased on deacclimatization. Of the fat lost, one-third was from the flat bones while one-half of the fat deposited on deacclimatization occurred in flat bones. The marrow water as well as the functional marrow (fat-free, by definition) in either the whole or the various parts of the skeleton was increased on acclimatization and decreased on deacclimatization.

High-Altitude Acclimatization Suppresses Hepcidin Expression During Severe Energy Deficit

2020 ◽  
Vol 21 (3) ◽  
pp. 232-236 ◽  
Author(s):  
Stephen R. Hennigar ◽  
Claire E. Berryman ◽  
Alyssa M. Kelley ◽  
Bradley J. Anderson ◽  
Andrew J. Young ◽  
...  
Keyword(s):  
High Altitude ◽  
Energy Deficit ◽  
Hepcidin Expression ◽  
Altitude Acclimatization ◽  
High Altitude Acclimatization
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