Sleep apnea
It is considered a "co-morbidity" for weight loss surgery, which means that insurance companies will factor it into a decision on whether or not to cover surgery, just as they do for high blood pressure, diabetes, and other complications of obesity.
If you have a sleep partner, you may already have a good indication of whether or not you have it. Do you snore? In between snores do you stop breathing? That's the apnea part. When I was diagnosed, I would stop breathing 60 times an hour. And every time you do that, you cut off oxygen to the brain, increasing your risk of strokes and all other nasty things. Not to mention that every time you stop breathing you wake up, so you never feel like you got a good nights sleep.
The test is an overnight one, usually in a sleep clinic, where they have a room set up like a luxury hotel. Before you go to sleep, they'll hook you up with patches and wires on your head, chest, and legs (if they're also testing for restless legs syndrome). Then you go to sleep like you normally do while a technician in another room monitors your sleep. And even if you think you haven't sleep a wink, they can tell if you did just by the brain waves.
If you do have sleep apnea, they may want to set you up with a device called a CPAP (Continuous Positive Airway Pressure). It's a mask or nasal "pillows" on your face connected to tubing to the machine, which will blow enough air through your mask to keep your airways open. It takes a few weeks to get used to, but it can truly save your life.
Since weight is one of the chief causes of sleep apnea, losing weight often cures it. I had another sleep test last summer and was told I was cured.
Good luck to you!
In regard to testing, there is also a home test, which I had. You go to an informational appt., take the test kit home, hook yourself up overnight, and return the machine the next day.
I have mild sleep apnea, and because I'm having surgery, I have to use the machine. Have to be on the machine for one month before surgery.