Ascorbic acid enhances hypoxic ventilatory reactivity in elderly subjects

The reducing properties of ascorbic acid in the carotid body make it a likely modifier of hypoxia-sensing mechanisms. This open-label study aimed to determine the effect of ascorbic acid on the hypoxic ventilatory response (HVR) in a population of elderly women, in whom both hypoxic reactivity and ascorbic acid levels may be deficient. We examined the HVR to progressive eucapnic hypoxia in 18 healthy females aged 60-80 years, before and after 10 days' ascorbic acid supplementation, given as a sustained release preparation of 1 g twice daily. Respiratory variables were recorded breath by breath, and hypoxic sensitivity was assessed from the linear slopes of minute ventilation and mouth occlusion pressure plotted against oxygen saturation. We found that ascorbic acid increased the HVR by a mean of 44%, this effect being driven by a higher occlusion pressure. We conclude that augmentation of hypoxic reactivity by ascorbic acid may have therapeutic potential in pathologies associated with hypoxia, which frequently develop in old age.