-LRB- CNN -RRB- -- It 's been nine years since Kim and Curtis Christiansen were married . Since then they 've had their ups and downs , but they 've remained close . But when Curtis began snoring about three years ago , Kim began sleeping on the couch . After his snoring drove his wife , Kim , to sleep on the couch , Curtis Christiansen saw a sleep specialist . `` His snoring was so loud . At first I would just elbow him to wake him up , '' she said , `` But then I became concerned . He would just -LRB- she gasps for breath -RRB- . It would take his breath away . '' At first Curtis Christiansen figured he was tired , a little run down from his job . He thought the snoring was just a symptom of his exhaustion . But when he started nodding off while waiting at a traffic light , he knew something was wrong . `` I became more aware of this choking and waking-up feeling , '' he said . Kim Christiansen finally persuaded her husband to go to a sleep specialist . The diagnosis : obstructive sleep apnea . According to the National Sleep Foundation , more than 18 million American adults have sleep apnea , and many of them do n't know it . Some people think their snoring is just a side effect of a busy lifestyle . Watch more on the difference between sleep apnea and snoring '' In some cases , that 's true . But the foundation says it 's trying to get more people to realize how important it is to know the difference between occasional snoring and apnea . Studies have shown that sleep apnea has some serious side effects . A disorder in which breathing is briefly and repeatedly interrupted during sleep , apnea occurs when the muscles in the back of the throat fail to keep the airway open , despite efforts to breathe . That can cause broken sleep patterns and low blood oxygen levels . Doctors say these side effects can lead to hypertension , heart disease , and mood and memory problems . In a recent study at the University of Maryland Medical Center , researchers found that sleep apnea can cause a rise in depression and that sleep-related breathing disorders can also worsen nightmares and post-traumatic stress disorder . And because sufferers are usually sleepy during the day , apnea can increase the risk of automobile crashes . There 's no question it can be life-threatening , doctors say . So how do you know whether your snoring is something more serious ? When snoring starts to affect your daily habits , you should see a doctor , said Dr. Thomas LoRusso , director of the Northern Virginia Sleep Diagnostic Centers . `` A bed partner may notice that the patient stops breathing and snores loudly , '' LoRusso said . `` And the daytime symptoms are sleepiness , poor concentration , problems waking up in the morning . '' LoRusso says a good way to check your sleep habits is to note your levels of fatigue during the day and jot down other symptoms you might be having . And if you have a bed partner , ask whether he or she has noticed any `` choking or gasping while you snore , '' he said . `` The person you sleep with , many times , knows your snoring better than you . '' Specific lifestyle changes can help you avoid sleep apnea , the sleep foundation said . LoRusso agrees . `` Cut out the alcohol , '' he said . `` It can make the upper airway muscles to relax . '' And watch your weight . Losing pounds can `` cure '' sleep apnea , especially for overweight people , LoRusso said . If you smoke , try to quit , he said . Smoking creates swelling in the upper airway , making apnea worse . These seemingly small changes can have dramatic results . `` In some cases , changing these factors can eliminate sleep apnea from some patients , '' LoRusso said . For Curtis Christiansen , it was n't that easy . Not only was he thin and a non-smoker , he suffered from high blood pressure and high cholesterol and , because of a previous health issue , had only one kidney . He needed help immediately . His doctor recommended a device called a CPAP , or continuous positive airway pressure device . It 's a mask or nose piece that blows air into the airway to keep it open while a patient sleeps . Although surgery is an option for those who have problems even with the CPAP , Christiansen was n't one of them . Since his diagnosis , Christiansen has gotten his blood pressure under control . When he started wearing the CPAP , he confesses , he 'd leave it behind when he went out of town . `` But I found I was n't getting a good night 's sleep , so now I take the CPAP along , '' he said with a smile , `` and I have a restful vacation with my wife . ''