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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 1: O2 toxicity: exercise / O2 interactions during hyperoxic work in dry chamber.

Stressors: hyperoxia; exercise, CO2.

Date: 1988-1990

Expt. Title: CNS & VISUAL O2 tolerance in physical work at 2.0 ATA (Expt. 13.00)

Description: See PS VII experiment protocols. Reports. Two series of investigations with different patterns of exercise (intermittent and incremental) during inspiration of O2 at 2.0 ATA in a dry pressure chamber. Emphases on central nervous system and visual aspects of O2 poisoning.

Multiple physiological functions were measured and monitored in 10 men during intermittent exercise, which consisted of two 30-min. periods of bicycle ergometry (150 watts: CO2 excretion rate = 1.802 and 1.734 l/min). Air controls were at 1.0 ATA (Expt. 13.12).

Multiple physiological functions were measured and monitored during incremental exercise in 9 men was at 50, 100, 150 and 200 watts (CO2 excretion rates of 0.786, 1.164, 1.785, and 2.534 l/min) (Expt. 13.12).

Results (no symptoms or signs of CNS or visual O2 toxicity) contrasted to findings of Butler and Thalmann that 4 of 40 divers experienced leg twitching near the end of one 30-min. period of exercise underwater at a slightly lower workload during hyperoxia at 2.06 ATA.

Measurements:

CNS Functions
Electroencephalograph
Mental and Psychomotor Performance:
Visual Digit Span Test of Span Memory (PMS Test I-1)
Operations Tests of Numerical (Reasoning) Ability (PMS Test K-1)
Visual Reaction Time Test of Reaction Speed (PMS Test C-1)
Key Insertion Test of Finger Dexterity (PMS Test B-1)

Visual Functions
Visual evoked response, visual acuity, accommodation, pupillometry, electroretinogram, visual fields

Pulmonary Functions
FVC, FEV₁, PEFR, FEF_25-75 (from flow-volume loop)

Ventilation and Gas Exchange    
Ventilation, frequency, tidal volume, rates of CO2 excretion, rate of O2 uptake (1.0 ATA air control), arterial blood gases and pH (2.0 ATA)

Cardiovascular functions and body temperature
Heart rate, cardiac stroke volume, systolic and diastolic blood pressures, core temperature

REPORT: Clark, J.M., R. Gelfand, W.C. Stevens, G. Beck, Jr., D.G. Fisher, and C.J. Lambertsen. Human tolerance and physiological responses to exercise and O2 breathing at 2.0 ATA in Predictive Studies VII. Aviat., Space, Environ. Med., 66 (4): 336-45, 1995.

REPORT: Stevens, W.C., J.M. Clark, R. Gelfand, and C.J. Lambertsen. The effect of hyperbaric O2 on selected cardiovascular and thermoregulatory parameters during exercise. Med. and Science in Sports and Exercise (ABSTRACT). 22(2) (Supp.): S91, 1990.

REPORT: Stevens, W.C., J.M. Clark, R. Gelfand and C.J. Lambertsen. Interacting effects of 2 ATA inspired PO2 and exercise on pulmonary ventilation and arterial PCO2. (ABSTRACT). Undersea Biomed. Res. 17 (S): 163, 1990.

REPORT: Stevens, W.C., J.M. Clark, A.M. Paolone, R. Gelfand and C.J. Lambertsen. Interacting effects of 2 ATA inspired PO2 and exercise on cardiopulmonary parameters (ABSTRACT). Undersea Biomed. Res. 18 (S): 89-90, 1991.

07 February 2000 11:05:45 AM