[abstract] THE RELATIONSHIP BETWEEN DECREASED MAXIMAL WORK PERFORMANCE AND VENTALITORY CAPACITY AT 2.1 MPa

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[abstract] THE RELATIONSHIP BETWEEN DECREASED MAXIMAL WORK PERFORMANCE AND VENTALITORY CAPACITY AT 2.1 MPa

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Title: [abstract] THE RELATIONSHIP BETWEEN DECREASED MAXIMAL WORK PERFORMANCE AND VENTALITORY CAPACITY AT 2.1 MPa
Author: Hashimoto, A; Takaai, Y; Shinkai, M; Ohara, I; Sugihara, K; Suzuki, S
Abstract: BACKGROUND: There have been a few studies relating the degree of work performance deterioration to the decrease of ventilatory capacity in hyperbaric environment. In the present study, we measured the maximal oxygen uptake (VO2max), maximal voluntary ventilation (MVV), and flow-volume (F-V) curve during forced vital capacity (FVC) maneuver to clarify the relationship between the decreased maximal work performance and ventilatory capacity at 2.1 MPa in a 200m helium-oxygen saturation dive simulation (PO2=42-50 kPa). METHODS: Six uninformed divers underwent a saturation dive simulation at 2.1 MPa (relative gas density = 4) and served as subjects. VO2 and heart rate (HR) were measured during the bicycle ergometer exercise at workloads of light to moderate (25, 75, 100 and 125 watts) in addition to exhaustion for VO2max. MVV and F-V curve during forced vital capacity maneuver were also measured. All measurements were performed once before (pre-dive as control), twice during, and right after the dive (post-dive). Paired t-test was employed for statistical analysis and p less than 0.05 () was considered significantly different. RESULTS: AT 2.1 MPa, expiratory/inspiratory flow rates at lung volumes of 50 to 75percent of FVC, and peak and mean expiratory/inspiratory flow rates during MVV maneuver decreased to about 55 to 60percent of respective control values. MVV decreased in average from 200 (control) to 116 L/min (2.1 MPa) by 43percent. HR tended to be greater at moderate workloads at 2.1 MPa and post dive but did not change at exhaustion, compared with control. VO2 tended to be higher at moderate workloads but lower by 9.3percent at exhaustion at 2.1 MPa that respective control values. Minute Ventilation (VE) during exercise showed the same tendency as VO2. The maximal VE at exhaustion was was much lower than MVV in control (131 vs. 200 L/min), but became close to MVV at 2.1 MPa (104 vs. 117 L/min). CONCLUSIONS: At 2.1 MPa, ventilatory capacity in general decreased by 40 to 45percent while VO2max decreased much less. This finding suggests that the maximal work performance could be limited by the decreased ventilatory capacity in the hyperbaric environment, but the limiting factor(s) would be different in one atmospheric air.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: http://archive.rubicon-foundation.org/857
Date: 1999

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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