We’ve all known someone whose snoring is so loud, irregular, or explosive that it is the subject of jokes. (It’s not so funny if you’re the snorer’s sleeping partner, of course.) Typical is the tale of the soldier who’s snoring so resonated that all of his platoon’s air mattresses vibrated to the sound of it.

But rather than serving as the occasion for laughter, some snoring ought to be taken extremely seriously, according to the National Institute of Health. In fact, some snoring should be heard as a loud warning of a potentially life-threatening health problem known as sleep apnea.

This condition occurs when the airway through which we breathe becomes constricted or obstructed. When we sleep, all of us experience a certain amount of relaxation of the tissues in our airways. But for people who have sleep apnea, there is too much relaxation, causing the airway to narrow or close. This leads to shallow breathing or to pauses in breathing that may last from a few seconds to minutes. These pauses can occur up to 30 times per hour, putting stress on the heart and other organs as the body continually rescues itself from oxygen deprivation. After the break, normal breathing then starts again, often with the characteristic loud snort or choking sound that is so often the butt of jokes.

Because sleep apnea occurs when one is asleep, it often can go undiagnosed, particularly in people who live and sleep alone. A telltale daytime symptom is unusual drowsiness that leads to frequent dozing. But because daytime sleepiness can stem from other causes, it takes a doctor to determine that sleep apnea is the culprit. In most cases it is a sleeping partner who raises the alarm about the problem.

There are two variations on this condition, obstructive sleep apnea and central sleep apnea. The former is associated with interrupted breathing and snoring during sleep. Central sleep apnea may not be evidenced by snoring, since it happens when the brain fails to send signals to keep the sleeper breathing.

If you suspect you have sleep apnea, consult a doctor. You may be sent to a sleep lab where your condition’s type and severity can be assessed.

For those who experience sleep apnea only when sleeping on their backs, help can be as simple as sewing a tennis ball into the back of a pajama shirt to keep the sleeper positioned on one side.

Other treatments range from surgery to the use of a respirator overnight. It can be a lifesaver to treat this disorder, since when left untreated, sleep apnea can cause high blood pressure, accidents related to excessive drowsiness, and even heart failure.