Obstructive sleep apnea (OSA) is a common disorder with major cardiovascular sequelae, including increased systemic hypertension and strokes. OSA is highly prevalent among patients with cardiovascular disease (CVD), but OSA remains under-diagnosed, thus under-treated. Furthermore, a recent study confirmed that OSA is associated with impaired exercise capacity and increasing OSA severity predicts worsening exercise capacity, which is a marker of potential increased cardiovascular risk. However, potential mechanisms of decreased exercise capacity caused by OSA remain unclear.