PMID- 14556564
OWN - NLM
STAT- MEDLINE
DCOM- 20040120
LR  - 20131121
IS  - 0095-6562 (Print)
IS  - 0095-6562 (Linking)
VI  - 74
IP  - 10
DP  - 2003 Oct
TI  - Submaximal exercise with self-contained breathing apparatus: the effects of 
      hyperoxia and inspired gas density.
PG  - 1040-7
AB  - BACKGROUND: The self-contained breathing apparatus (SCBA) used by firefighters, 
      and other working in dangerous environments, adds an external resistance to 
      expiration, which increases expiratory work during heavy exercise. HYPOTHESIS: 
      Compressed air is typically used with the SCBA and we hypothesized that changing 
      the inspired oxygen concentration and/or gas density with helium would reduce the 
      external expiratory resistance. METHODS: On separate days, 15 men completed four 
      30-min bouts of treadmill exercise dressed in protective clothing and breathing 
      the test gases through the SCBA. Four different gas mixtures were assigned in 
      random order: [compressed air (NOX: 21% O2, 79% N2), hyperoxia (HOX: 40% O2, 60% 
      N2), normoxic-helium (HE-OX: 21% O2, 79% He), and helium-hyperoxia (HE-HOX: 40% 
      O2, 60% He)]. RESULTS: Compared with NOX, the two helium mixtures (but not HOX), 
      decreased the external breathing resistance and all three gas mixtures decreased 
      the peak expired mask pressure and the ventilatory mass moved. Both hyperoxic 
      mixtures decreased blood lactate and the rating of perceived exertion was 
      decreased at 30 min with HE-HOX. CONCLUSIONS: These results demonstrate that the 
      helium-based gas mixtures, and to a lesser extent HOX, reduce the expiratory work 
      associated with the SCBA during strenuous exercise.
FAU - Eves, Neil D
AU  - Eves ND
AD  - Faculty of Physical Education and Recreation, University of Alberta, Alberta, 
      Canada, T6G 2H9.
FAU - Petersen, Stewart R
AU  - Petersen SR
FAU - Jones, Richard L
AU  - Jones RL
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Aviat Space Environ Med
JT  - Aviation, space, and environmental medicine
JID - 7501714
RN  - 206GF3GB41 (Helium)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Administration, Inhalation
MH  - Adult
MH  - Airway Resistance
MH  - Exercise/*physiology
MH  - Exercise Test
MH  - Fires
MH  - Helium/*pharmacology
MH  - Humans
MH  - Male
MH  - *Occupational Exposure
MH  - Oxygen/administration & dosage/*pharmacokinetics
MH  - Pressure
MH  - *Respiratory Protective Devices
MH  - *Work of Breathing
EDAT- 2003/10/15 05:00
MHDA- 2004/01/21 05:00
CRDT- 2003/10/15 05:00
PHST- 2003/10/15 05:00 [pubmed]
PHST- 2004/01/21 05:00 [medline]
PHST- 2003/10/15 05:00 [entrez]
PST - ppublish
SO  - Aviat Space Environ Med. 2003 Oct;74(10):1040-7.