Gender Differences in Respiratory Response to Exercise and Hypoxia

EMBARGOED UNTIL OCTOBER 18, 2001

Contact: Donna Krupa at: 703.527.7357 or Cell: 703.967.2751 [email protected]

Or At the APS Newsroom @ The Westin Convention Center, Pittsburgh, PA October 17-20, 2001Tel: 412.281.3700 (The Crawford Room)

GENDER DIFFERENCES IN RESPIRATORY RESPONSE TO EXERCISE AND HYPOXIA

PITTSBURGH -- Pa., -- Neural and chemical mechanisms interact in adjusting breathing pattern and ventilation during exercise. Dr. Magdalena Seebauer of the Institute of Physiology, University of Zurich, Switzerland, investigated gender differences in these interactions by analyzing phase coordination of breathing and exercise rhythms during bicycling in normoxia and hypoxia corresponding to 4000m altitude.

Dr. Seebauer will discuss the findings during the upcoming conference, Genomes and Hormones: An Integrative Approach to Gender Differences in Physiology, being sponsored by the American Physiological Society (APS), and held October 17-20, 2001 at the Westin Convention Center, Pittsburgh, PA.

MethodologyDr. Seebauer and her colleagues examined 22 men and 22 women (19-41 years) who underwent exercise tests of six minutes at workloads of 50, 80 and 110 percent of their anaerobic threshold (AT). Continuous breath-by-breath recordings of several respiratory parameters, oxygen saturation and leg movement were carried out. Ventilatory response to hypoxia (HVR) was determined by a four minute exposure to isocapnic hypoxia.

Results In normoxia, men coordinated distinctively more at 110 percent AT than at 50 percent AT, whereas in women, coordination remained nearly constant. At 110 percent AT men reduced the degree of coordination from normoxia to hypoxia, whereas in women, coordination increased. HVR tended to be lower in women than in men.

ConclusionsThe investigators concluded that in men, the degree of coordination depends on workload level and on hypoxia, whereas in women, coordination remains stable regardless of experimental condition. The higher chemosensitivity in men may account for the reduction of coordination in hypoxia.

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***Editor's Note: To set up an interview with Dr. Seebauer, please contact Donna Krupa in the APS newsroom at 412.281.3700 (the Crawford Room). After newsroom hours, contact 703.967.275l (cell), 703.527.7357 (office) or [email protected] (email).