Dying a little bit at a time, every single night

Nothing can ruin your day quite like a lousy night -- but if you suffer from sleep apnea, you're having lousy nights every single night.

And you might not even realize it.

Sleep apnea, if you're not familiar with it, is a terrifying condition in which you literally stop breathing in your sleep. These episodes can last anywhere from a few seconds to a minute or more -- but because they take place while you're asleep, you'll be completely unaware of them.

All you'll know is you don't feel as rested as you used to, even when you hit the sack earlier than ever.

But the risks of apnea go far beyond waking up grouchy and yawning all day -- it's a major risk factor for a number of diseases and even an early death, and a new study shows how it can cause your risk of death by cancer to skyrocket.

The study of more than 1,500 participants tracked for up to 22 years as part of the Wisconsin Sleep Cohort finds that people with the most severe sleep apnea -- those with 30 or more episodes every hour -- have nearly five times the risk of death by cancer than those who sleep normally.

Less severe apnea had less severe risks -- but still risks you don't need.

Moderate apnea, for example, doubled the risk of cancer death, while mild apnea increased the risk by 10 percent, according to the data presented at the Thoracic Society International Conference.

If death by cancer was the only risk of sleep apnea, that would be enough of a reason to avoid it in my book -- but it's not.

Other studies have found that people with sleep apnea have a higher risk of heart disease and brain damage, including a loss of gray matter and even dementia. These are more than just theoretical links. Both your heart and brain need oxygen -- and when you stop breathing, they don't get that oxygen.

But as I mentioned earlier, part of the problem with sleep apnea is that most people don't even realize they have it.

Along with finding yourself tired for no reason, warning signs including waking up with a headache, dry mouth and/or a sore throat. If you have a spouse, he or she may notice heavy snoring.

A spouse can also keep watch over you for a night and monitor your breathing as an informal test, but the only way to really know for sure is to spend a night in a sleep clinic.

If it turns out you do have apnea, or if you even think you have apnea, treatments range from surgical procedures to a device called the continuous positive airway pressure (CPAP) machine.

It's basically an oxygen mask that you wear all night, but it's so uncomfortable that many people can't sleep with it.

There are other alternatives such as dental devices or nasal patches, but the best way to end the apnea for good is by losing weight, because the leading cause of apnea is obesity.

Once you shrink your waistline, you'll find yourself breathing better all the time -- not just at night.