Name: _______________________________
1
Laboratory Session 9: Cardiovascular Function During Acute Hypoxia
Background
The Exercise Science Program at UNM owns a hypo- and hyper-barometric chamber, which is
located next to Carlisle Gym. This facility has been used in research, and is also a great teaching aid
to expose students to the stress of higher altitude (simulated by decreasing pressure inside the
chamber).
During acute exposure to increasing altitude (lower pressure), the body’s alveolar partial pressure of
oxygen (PAO2) decreases in a near linear manner with the lower pressure. This causes a slight
reduction in PaO2 and the saturation of hemoglobin (though well preserved for low to moderate
altitude due to the oxy-hemoglobin dissociation curve), so that there is less oxygen content of arterial
blood. To compensate, there is an increase in ventilation and heart rate. The mild hyperventilation
raises PAO2 and PaO2 slightly (though PAO2 is still lower than if at a lower altitude), and the
increased heart rate functions to raise cardiac output so that blood oxygen delivery remains similar to
normoxia (normal oxygen content of inspired air).
Purpose
The purpose of this laboratory is to expose students to hypobaric hypoxia (hypoxia induced by
lowering atmospheric pressure). During exposure to altitudes of 5,000 (baseline), 7,000, 10,000,
13,000 and 16,000 ft, data will be recorded from each student for heart rate, SaO 2 (arterial oxyhemoglobin saturation) and ventilation rate.
Methods
Participation in this lab is voluntary, and students who volunteer and are healthy with no symptoms of
airway congestion, common cold, or history of claustrophobia, will enter the chamber. Air will be
suctioned from the chamber at a rate equivalent to an altitude change of 1,000 ft/min.
Prior to the development of hypobaric hypoxia, measures of heart rate, SaO 2 and ventilation rate will
be made on each student. The same measures will be made at each of 7,000, 10,000, 13,000, and
16,000 ft.
Data Processing
Get a copy of the data from Dr. Robergs (will be made as an Excel file and attached to the
Assignments web page for Lab 8). Use the formula mode to calculate the mean and standard
deviation data for all variables and conditions.
Perform 1-way ANOVA statistics on the change in each variable for the 5 altitude conditions. Dr.
Robergs will show you how to do this in lecture.
Results
Graph the meanSD data for each variable, and use symbols to show means that are significantly
different.
Discussion
Comment on how the oxy-hemoglobin dissociation curve minimizes reductions in PaO2 during
hypoxia.
How does acute altitude exposure alter VO2max? Why?
What does a sustained hyperventilation do to blood acid-base balance?
What would be good and bad for living at higher altitude and its impact on exercise performance?
Name: _______________________________
2
References
1: Fukuda T, Maegawa T, Matsumoto A, Komatsu Y, Nakajima T, Nagai R, Kawahara T. Effects of
acute hypoxia at moderate altitude on stroke volume and cardiac output during exercise. Int Heart J.
2010 May;51(3):170-5.
2: Mollard P, Bourdillon N, Letournel M, Herman H, Gibert S, Pichon A, Woorons X, Richalet JP.
Validity of arterialized earlobe blood gases at rest and exercise in normoxia and hypoxia. Respir
Physiol Neurobiol. 2010 Jul 31;172(3):179-83.
3: Vogt M, Hoppeler H. Is hypoxia training good for muscles and exercise performance? Prog
Cardiovasc Dis. 2010 May-Jun;52(6):525-33.
4: Kon M, Ikeda T, Homma T, Akimoto T, Suzuki Y, Kawahara T. Effects of acute hypoxia on
metabolic and hormonal responses to resistance exercise. Med Sci Sports Exerc. 2010
Jul;42(7):1279-85.
5: Lecoultre V, Boss A, Tappy L, Borrani F, Tran C, Schneiter P, Schutz Y. Training in hypoxia fails to
further enhance endurance performance and lactate clearance in well-trained men and impairs
glucose metabolism during prolonged exercise. Exp Physiol. 2010 Feb;95(2):315-30.
6: Sheel AW, MacNutt MJ, Querido JS. The pulmonary system during exercise in hypoxia and the
cold. Exp Physiol. 2010 Mar;95(3):422-30. Epub 2009 Oct 23.
7: Zupet P, Princi T, Finderle Z. Effect of hypobaric hypoxia on heart rate variability during exercise: a
pilot field study. Eur J Appl Physiol. 2009 Oct;107(3):345-50.
8: Bonetti DL, Hopkins WG. Sea-level exercise performance following adaptation to hypoxia: a metaanalysis. Sports Med. 2009;39(2):107-27.
9: Calbet JA, Robach P, Lundby C, Boushel R. Is pulmonary gas exchange during exercise in
hypoxia impaired with the increase of cardiac output? Appl Physiol Nutr Metab. 2008 Jun;33(3):593600.
10: Subudhi AW, Lorenz MC, Fulco CS, Roach RC. Cerebrovascular responses to incremental
exercise during hypobaric hypoxia: effect of oxygenation on maximal performance. Am J Physiol
Heart Circ Physiol. 2008 Jan;294(1):H164-71.
11: Amann M, Pegelow DF, Jacques AJ, Dempsey JA. Inspiratory muscle work in acute hypoxia
influences locomotor muscle fatigue and exercise performance of healthy humans. Am J Physiol
Regul Integr Comp Physiol. 2007 Nov;293(5):R2036-45.
12: Woorons X, Mollard P, Pichon A, Lamberto C, Duvallet A, Richalet JP. Moderate exercise in
hypoxia induces a greater arterial desaturation in trained than untrained men. Scand J Med Sci
Sports. 2007 Aug;17(4):431-6.
13: Péronnet F, Massicotte D, Folch N, Melin B, Koulmann N, Jimenez C, Bourdon L, Launay JC,
Savourey G. Substrate utilization during prolonged exercise with ingestion of (13)C-glucose in acute
hypobaric hypoxia (4,300 m). Eur J Appl Physiol. 2006 Jul;97(5):527-34.
Name: _______________________________
14: Dufour SP, Ponsot E, Zoll J, Doutreleau S, Lonsdorfer-Wolf E, Geny B, Lampert E, Flück M,
Hoppeler H, Billat V, Mettauer B, Richard R, Lonsdorfer J. Exercise training in normobaric hypoxia in
endurance runners. I. Improvement in aerobic performance capacity. J Appl Physiol. 2006
Apr;100(4):1238-48.
15: Zoll J, Ponsot E, Dufour S, Doutreleau S, Ventura-Clapier R, Vogt M, Hoppeler H, Richard R,
Flück M. Exercise training in normobaric hypoxia in endurance runners. III. Muscular adjustments of
selected gene transcripts. J Appl Physiol. 2006 Apr;100(4):1258-66.
16: Robergs RA, Quintana R, Parker DL, Frankel CC. Multiple variables explain the variability in the
decrement in VO2max during acute hypobaric hypoxia. Med Sci Sports Exerc. 1998 Jun;30(6):86979.
3