Respiratory, cerebrovascular and cardiovascular responses to isocapnic hypoxia

► Novel responses to isocapnic hypoxia for ventilation, cerebral blood flow, blood pressure and heart rate were observed. ► Heart rate responses were correlated with ventilation; cerebral blood flow responses were correlated with blood pressure. ► Hyperoxic and hypoxic ventilatory CO2 responses can be derived from hypoxic ventilatory responses at 3 isocapnic levels.