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P ET CO 2 in Women at Sea‐Level and Upon Acute Exposure to a Normobaric Hypoxic Environment Simulating 3,500 m
Author(s) -
Yasukawa Michio,
Degarmo Anna,
Quiroga Leonardo,
Muza Stephen,
Kambis Ken
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.909.1
Subject(s) - medicine , tidal volume , anesthesia , hypobaric chamber , volunteer , heart rate , hypoxia (environmental) , zoology , effects of high altitude on humans , respiratory system , oxygen , chemistry , blood pressure , anatomy , organic chemistry , biology , agronomy
While prior work (Muza, J. Appl. Physiol. 91: 2001) suggests that women and men have similar responses to high altitude, no studies have attempted to develop gender specific predictive values for end‐tidal CO 2 (EtCO 2 ) in a normobaric hypoxic (NH) environment simulating acute exposure to an altitude of 3,500 m based on sea‐level (SL) EtCO 2 values. As part of a larger study examining individual variability upon acute exposure to NH, EtCO 2 , heart rate (HR), and respiratory rate (RR) were measured in 107 subjects at sea level (SL) who, no sooner than two days later, entered a normobaric hypoxia chamber at approximating O 2 partial pressures equivalent to those found at 3,500 m. METHODS Participants in this IRB‐approved study included: 63 informed volunteer female subjects (56 Treatment [NH]: 20.5±1.5 yr.; 165.8±6.9 cm; 63.011.1 kg; 22.93.3 BMI; 7 SHAM: 20.31.1 yr; 167.56.2 cm; 57.26.2 kg; 20.46.4 BMI); 44 informed volunteer male subjects (35 Treatment [NH]: 20.31.3 yr; 178.26.8 cm; 77.414.0 kg; 24.23.2 BMI; and 9 SHAM: 20.71.0 yr; 179.87.8 cm; 73.310.0 kg; 22.73.1 BMI). All subjects were tested at SL then again 2+ days later after entering a NH (FiO 2 =13.55%) chamber where EtCO 2 , HR, and RR were measured after 30 minutes of rest. RESULTS Bonferroni t‐tests revealed no difference in female or male EtCO 2 between the SL and SHAM conditions while, as expected, there was a difference (P≤0.05) in EtCO 2 between the SL and NH conditions in the female treatment group (37±3 vs. 36±3 mmHg) and the male treatment group (39±3 vs. 37±2 mmHg). RR and HR remained unchanged in the female and male groups in all conditions. CONCLUSIONS Using the following algorithm, we were able to predict EtCO 2 in female subjects at the P 0.001 level of confidence [Actual vs. Predictive (EtCO 2 at FiO 2 = 13.55%) Y = 86.394 – 0.221X 1 ‐ 0.541X 2 (Where Y = EtCO 2 _HYPO, X 1 = RR_NH, X 2 = SpO 2 _NH, R 2 = 0.520, P<0.001] while the predictive value of the male data was not significant (R 2 = 0.099, P = 0.187). Therefore, female responsiveness to acute exposure to simulated altitude may be greater than that of male peers. Support or Funding Information: The Chuo University Oversea Research Program, The Doug Morton/Marilyn Brown Endowment for Biomedical Research, The Foundation for Aging Studies and Exercise Science Research, and The Borgenicht Program