Studies on organ weights in naproxen treated rats after intermittent exposure to simulated high altitude

1990 ◽  
Vol 34 (2) ◽  
pp. 90-92 ◽  
Author(s):  
R. C. Saha ◽  
H. M. Biswas
Keyword(s):  
High Altitude ◽  
Organ Weights ◽  
Simulated High Altitude ◽  
Intermittent Exposure

Reduction of ICa,Land Ito1Density in Hypertrophied Right Ventricular Cells by Simulated High Altitude in Adult Rats

1997 ◽  
Vol 29 (1) ◽  
pp. 193-206 ◽  
Author(s):  
Christophe Chouabe ◽  
Leon Espinosa ◽  
Pierre Megas ◽  
Abderrazak Chakir ◽  
Oger Rougier ◽  
...  
Keyword(s):  
Right Ventricular ◽  
High Altitude ◽  
Adult Rats ◽  
Ventricular Cells ◽  
Simulated High Altitude

Relationship between Behavior in a Stress Situation and Later Separation from Flight Training with Expressed Anxiety toward Flying

1956 ◽  
Vol 2 (3) ◽  
pp. 393-397
Author(s):  
Robert B. Voas ◽  
John T. Bair ◽  
Rosalie K. Ambler
Keyword(s):  
High Altitude ◽  
Training Program ◽  
Flight Training ◽  
Stress Situation ◽  
Simulated High Altitude ◽  
Development Of Anxiety ◽  
The Relationship

The purpose of this research was to determine the relationship between reactions of cadets during simulated high altitude in a decompression chamber and the later development of anxiety toward flying as reported in terminal interviews. The results for 1540 cadets indicated that significantly more of those who withdrew because of anxiety toward flying had anxiety reactions in the decompression chamber than of those who completed the Naval Air Training Program.

Acute hypoxia in a simulated high-altitude airdrop scenario due to oxygen system failure

2017 ◽  
Vol 123 (6) ◽  
pp. 1443-1450 ◽  
Author(s):  
William Ottestad ◽  
Tor Are Hansen ◽  
Gaurav Pradhan ◽  
Jan Stepanek ◽  
Lars Øivind Høiseth ◽  
...  
Keyword(s):  
High Altitude ◽  
Acute Hypoxia ◽  
Supplemental Oxygen ◽  
Cerebral Oximetry ◽  
Arterial Oxygen ◽  
Hypoxic Exposure ◽  
System Failure ◽  
Oxygen System ◽  
Simulated High Altitude ◽  
Oxygen Tensions

High-Altitude High Opening (HAHO) is a military operational procedure in which parachute jumps are performed at high altitude requiring supplemental oxygen, putting personnel at risk of acute hypoxia in the event of oxygen equipment failure. This study was initiated by the Norwegian Army to evaluate potential outcomes during failure of oxygen supply, and to explore physiology during acute severe hypobaric hypoxia. A simulated HAHO without supplemental oxygen was carried out in a hypobaric chamber with decompression to 30,000 ft (9,144 m) and then recompression to ground level with a descent rate of 1,000 ft/min (305 m/min). Nine subjects were studied. Repeated arterial blood gas samples were drawn throughout the entire hypoxic exposure. Additionally, pulse oximetry, cerebral oximetry, and hemodynamic variables were monitored. Desaturation evolved rapidly and the arterial oxygen tensions are among the lowest ever reported in volunteers during acute hypoxia. PaO2 decreased from baseline 18.4 (17.3–19.1) kPa, 138.0 (133.5–143.3) mmHg, to a minimum value of 3.3 (2.9–3.7) kPa, 24.8 (21.6–27.8) mmHg, after 180 (60–210) s, [median (range)], N = 9. Hyperventilation with ensuing hypocapnia was associated with both increased arterial oxygen saturation and cerebral oximetry values, and potentially improved tolerance to severe hypoxia. One subject had a sharp drop in heart rate and cardiac index and lost consciousness 4 min into the hypoxic exposure. A simulated high-altitude airdrop scenario without supplemental oxygen results in extreme hypoxemia and may result in loss of consciousness in some individuals. NEW & NOTEWORTHY This is the first study to investigate physiology and clinical outcome of oxygen system failure in a simulated HAHO scenario. The acquired knowledge is of great value to make valid risk-benefit analyses during HAHO training or operations. The arterial oxygen tensions reported in this hypobaric chamber study are among the lowest ever reported during acute hypoxia.

Effects of simulated high altitude on blood glucose levels during exercise in individuals with Type 1 Diabetes

2021 ◽  
Author(s):  
Cory W Dugan ◽  
Shane K Maloney ◽  
Kristina J Abramoff ◽  
Sohan S Panag ◽  
Elizabeth A Davis ◽  
...  
Keyword(s):  
High Altitude ◽  
Acute Hypoxia ◽  
Carbohydrate Oxidation ◽  
Normoxic Condition ◽  
Glucose Levels ◽  
Oxidation Rates ◽  
Blood Glucose Levels ◽  
Simulated High Altitude ◽  
The Impact

Abstract Context Current exercise guidelines for individuals with type 1 diabetes (T1D) do not consider the impact that high altitude may have on blood glucose levels (BGL) during exercise. Objective To investigate the effect of acute hypoxia (simulated high altitude) on BGL and carbohydrate oxidation rates during moderate intensity exercise in individuals with T1D. Methods Using a counterbalanced, repeated measures study design, 7 individuals with T1D completed two exercise sessions; normoxia and hypoxia (~4,200m simulated altitude). Participants cycled for 60min on an ergometer at 45% of their sea-level V̇O2peak, and then recovered for 60min. Before, during and after exercise, blood samples were taken to measure glucose, lactate and insulin levels. Respiratory gases were collected to measure carbohydrate oxidation rates. Results Early during exercise (<30min), there was no fall in BGL in either condition. After one hour of exercise and during recovery, BGL were significantly lower under the hypoxic condition compared to both pre-exercise levels (p=0.008) and the normoxic condition (p=0.027). Exercise in both conditions resulted in a significant rise in carbohydrate oxidation rates, which returned to baseline levels post-exercise. Before, during and after exercise, carbohydrate oxidation rates were higher under the hypoxic compared with the normoxic condition (p<0.001). Conclusions The greater decline in BGL during and after exercise performed under acute hypoxia suggests that exercise during acute exposure to high altitude may increase the risk of hypoglycemia in individuals with T1D. Future guidelines may have to consider the impact altitude has on exercise-mediated hypoglycemia.

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