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PREDICTIVE STUDIES VII (PS VII): Interactions of Hyperoxia, Exercise, and Immersion in Neurologic O2 Poisoning.
Major Category: Oxygen toxicity and oxygenation. Immersion. Exercise. (PS VII)
Subcategory 10: Partial and total immersion and exercise.

Stressors: immersion, exercise

Date: 1993-4

Expt. Title: Effects of Partial and total immersion on physiological responses to incremental exercise while breathing air at 1.0 atmosphere. (Expt. 13.01, 13.02, 13.03)

Description:

This was the second investigation using improved methods of holding the TCD probe in place without excessive pressure on the side of the skull, of eliminating interference with the TCD signal during full immersion and of regulating back pressure in the breathing system during immersion. Eight Subjects were studied at rest and during incremental exercise in the dry condition, then during head-out immersion, and finally during total immersion. Water temperature was kept at 32^o C. Air was breathed to facilitate measurements of O2 uptake rate during exercise. During exposure to each condition, a 10-minute rest period was followed by three 6-minute workloads consisting of 60, 110, and 150 watts at a pedal rate of 60 rpm in the dry and 30, 80, and 110 watts at 50 rpm during immersion. The subject was connected to the gas delivery and elimination systems by a low resistance (Hans Rudolph, "T" configuration valve assembly using tricuspid check valves). Two paralleled inspiratory demand regulators were adjusted in the water column to deliver inspired gas at pressure to balance the water column acting on the subject’s lungs. This pressure was maintained in the airway with an adjustable back pressure regulator at the expiratory end of the airway.

Measurements:

End-tidal CO2 tensions, mixed expired O2 and CO2 concentrations, airway pressure, ventilation and respiratory frequency, tidal volume, water and body temperatures, heart rate, MCA blood flow velocity,

REPORT: Gelfand, R., J.M. Clark, B.A. Youdelman, E.J. Hopkin, and C.J. Lambertsen. Effects of head-out and total immersion on ventilatory and cerebral circulatory responses to progressive exercise at 1.0 ATA in humans (ABSTRACT). Undersea and Hyperbaric Med. 21 (S): 37, 1994

07 February 2000 11:09:19 AM