An explanation was that poor breathing was associated with a reduction in the lung tissues available for gas exchange; thus, it may increase the chance of hypoventilation and chronic hypoxia and hypercapnia, which may affect neurocognitive function (Giltay et al., 2009); besides, elevated levels of systemic inflammation markers in patients with respiratory diseases, such as C-reactive protein, interleukin 6 and fibrinogen, might increase the risk of cognitive impairment (Su et al., 2016). Here, IL6 is linked to Cognitive impairment.