If you're always tired, sleep apnea—and other common sleeping problems linked to heart disease, weight gain, and more—could be to blame.

Until recently, doctors thought they had obstructive sleep apnea (OSA)-a condition that causes you to stop breathing for seconds at a time during the night, preventing you from getting restful sleep-all figured out. It mostly affected older, overweight men, they said. The top red flags were snoring and daytime fatigue. The only way to treat it was with a CPAP machine, which could be so noisy and uncomfortable that nearly half of sleep apnea sufferers eventually quit using it.

Well, it turns out there was a lot doctors didn't know. For starters, the condition-known to significantly increase your risk of high blood pressure, stroke, cancer, diabetes, depression, and obesity-is much more common in young, healthy women than previously believed: As many as half of ladies ages 20 to 70 have it to some degree, Swedish researchers found. And many of these sufferers are otherwise healthy. What's more, OSA seems more harmful to women's health than men's, according to research from UCLA School of Nursing. Could you be at risk?

Not Snoring Doesn't Mean You're Safe

Many women with the condition actually don't snore often or at all, says OSA expert Kathleen Bennett, D.D.S., president of the American Academy of Dental Sleep Medicine. "Even in trim, athletic women who don't snore, a narrow neck, large tongue, small mouth, and set-back jaw all indicate narrow airways, which are more prone to becoming blocked at night, especially if you sleep on your back," she explains.

You May Not Feel Tired

Daytime fatigue is one of the most common symptoms of the condition, stresses Bennett. But if you've had some form of OSA since childhood, she adds, you may be used to disrupted sleeping. "You might not even know what normal energy levels feel like, because you've felt some degree of fatigue since you were a kid." Other telltale symptoms include weepiness or daytime depression, low arousal or difficulty orgasming, and sugar cravings.

You Might Be Able To Skip the Sleep Study

In order to have insurance cover your treatment, you need to get a formal diagnosis. But luckily, that doesn't mean having to drag yourself to a sleep study lab for a night or two. Today-barring preexisting conditions or complications-many people are eligible for an at-home sleep study, says Bennett. Your doctor will have you sleep with sensors or monitors for a period of time, then he'll analyze the data and make recommendations.

A CPAP Machine Isn't the Only Treatment Option

Mouthpieces are nearly as effective-and since they're less disruptive, many more sleep apnea sufferers actually use them, says Bennett. (Just 50 percent of people who get diagnosed and try a CPAP end up using it every night; 76 percent of those with mouthpieces use them, report researchers in the journal CHEST.)