Research suggests that OSA is a major contributing factor in the development of hypertension, or high blood pressure. Data from a 2003 study in The New England Journal of Medicine, reveals that, "sleep-disordered breathing is likely to be a risk factor for hypertension and consequent cardiovascular morbidity in the general population." Although many patients with OSA have clear symptoms of hypertension, as many as 90 percent of cases are undiagnosed. In studies in which blood pressure was measured following treatment for obstructive sleep apnea, daytime and nighttime blood pressure levels were found to decrease significantly. This decrease in blood pressure may also reduce the likelihood of cardiovascular complications.

The apneas and hypopneas associated with obstructive sleep apnea decrease oxygen levels and increase carbon dioxide levels in the blood. As these levels become more extreme, sufferers begin to struggle for air - in essence suffocating — which causes them to wake up briefly and start breathing again. During each apnea, the stress on the body leads to an increase or irregularity of the heart rate and increased blood pressure. According to recent medical research, the stress caused by these irregular apneas may increase the risk for developing high blood pressure, cardiac arrhythmias and heart failure. In fact, according to a 2003 study in The New England Journal of Medicine, OSA sufferers have significantly increased odds of having heart failure.

People with obstructive sleep apnea often feel very sleepy during the day, which has a negative impact on their concentration and daytime performance. Long-term effects of OSA include depression, irritability, sexual dysfunction, learning and memory difficulties, and falling asleep while at work, on the phone or driving. In fact, studies show that sleep deprivation can lower a person's quality of life and increase the risk for accidents.