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Ventilatory Responsiveness during Exercise and Performance Impairment in Acute Hypoxia
Keren Constantini1, Anna C Bouillet1, Chad C Wiggins2
1Department of Kinesiology, Indiana University, Bloomington, IN.
Medicine and Science in Sports and Exercise
|July 23, 2020
Summary
Hypoxic ventilatory response (HVR) during exercise, not at rest, is crucial for mitigating performance decline in acute hypoxia. Adequate ventilation, not HVR gain, is key for endurance cycling performance under hypoxic conditions.
Area of Science:
- Exercise Physiology
- Environmental Physiology
- Human Performance
Background:
- Minute ventilation defends arterial oxyhemoglobin saturation (SpO2) during hypoxic exercise, explaining performance variations.
- Hypoxic ventilatory response (HVR) is typically measured at rest, limiting its predictive value for exercise performance under hypoxia.
Purpose of the Study:
- To compare resting and exercise HVR.
- To determine if exercise HVR predicts cycling time trial (TT) performance impairment from normoxia to acute hypoxia.
Main Methods:
- Sixteen endurance-trained men performed resting and cycling HVR tests.
- Twelve participants completed 10-km cycling TTs breathing room air or hypoxic gas mixtures.
Main Results:
- Exercise HVR was significantly greater than resting HVR and they were uncorrelated.
- Neither resting nor exercise HVR correlated with cycling TT performance impairment.
- Ventilation and end-tidal CO2 differences explained 85% of performance impairment variance.
Conclusions:
- Resting HVR is inappropriate for predicting exercise ventilatory response or performance in acute hypoxia.
- Adequate exercise ventilation, matched to metabolic demand, is essential for mitigating hypoxia-induced performance impairments.
- The gain in ventilatory response to hypoxia does not predict endurance cycling performance in acute hypoxia.
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