Effect of hypoxia on psychomotor performance during graded exercise.

We evaluated the combined effects of reduced O2 (12%) and graded ergometer exercise (10, 70, and 140 W) on the performance of a psychomotor task. Six men participated in two test sessions each. Each session began with the baseline data (air) and finished with exposure data (12% or 21%, random, unidentified).

Symptomatology during hypoxic exposure to flame-retardant chamber atmospheres.

Hypoxia was studied in 12 men during 63-h exposures to 17 and 13% O2, with the subjects serving as their own controls by repeating the measurements in 21% O2. All test atmospheres were contaminated with 0.9% CO2 to simulate the condition of living aboard submarines.

Submarine atmospheres.

Nuclear submariners live and work in an atmosphere composed of approximately 80% naturally occurring nitrogen, 19% oxygen (manufactured aboard ship), and a complex mixture of inorganic and organic contaminants. The concentrations of contaminants exist as a balance between the rates of production from human and operational activities and the rate of removal by engineering systems. The biological effects of inorganic gases, particularly carbon dioxide, have been extensively studied.

Carbohydrate metabolism in U.S. Navy submarine personnel.

One- and two-hour postprandial glucose and insulin values were measured in 58 submariners with 5 or more FBM patrols and in 58 non-submariners. An interrelationship between serum glucose and insulin for classifying defects in carbohydrate metabolism indicated that 55% of the submariners and 45% of the non-submariners exhibited some type of defect. Exercise appears to play an important role in the maintenance of normal carbohydrate metabolism in these subjects.

Blood volume responses in partially dehydrated subjects working in the cold.

The effects of high-salt diets, cold, and heavy exercise have been examined in 33 Marine Corps volunteers living and working in a cold chamber. Temperatures varied from -29 degrees C during working hours to -4 degrees C, simulating partly warmed shelters, at night. Dehydrated operational rations were eaten and fluid intakes were controlled.