We found a pattern of higher BRV indicating higher breathing instability in patients with OSA compared with healthy participants during wakefulness. Similarly, a higher BRV was elicited by a 30-second BH challenge in patients with OSA, whereas BRV in healthy participants returned to baseline levels immediately after the same BH challenge. BRV is tightly linked with cardiovascular patterns, including BP, through respiratory and autonomic neural circuitry. Such neural circuitry is impacted by OSA, and altered neural function may contribute to the instability of cardiorespiratory physiology observed in OSA. Future studies could assess whether BRV covaries with BPV in OSA. Since CPAP resolves some neural dysfunction in OSA, another question is whether CPAP treatment also normalizes some cardiorespiratory physiology during wakefulness. More generally, this study found that BRV is a potentially informative marker of a physiological state specific to people with OSA.
