Want to see something really scary? Check out this video.

The night vision security camera might make it look like the latest edgy documentary-style horror flick -- but there's no paranormal activity here.

This is 100 percent real.

It's a man with sleep apnea. Watch as he stops breathing. Try to hold your breath along with him -- just don't try too hard, because you might pass out: The man stops breathing for a full 40 seconds.

But here's what's truly frightening: This could be happening to you repeatedly every single night... and you might not even know it.

Unless your spouse has seen you gasping for air in the night or -- like the man in this video -- you've spent a night in a sleep clinic, there's no way to know for sure whether or not you have this breath-robbing condition.

But if you're overweight or obese, you're playing with fire already -- because weight is the top risk factor for sleep apnea. And as this condition sucks the air from your lungs, it cuts off the flow of oxygen to your brain and heart, putting both at risk.

That's why apnea has been linked to dementia, heart problems, depression, mood swings, an early death and more.

One new study finds that women with apnea have a 350 percent higher risk of death from heart disease than women without it. Other studies have found a similar story for men.

You can try to fight it with an oxygen mask, but who wants to sleep with one of those every night?

Lose the weight instead -- and do it before you find yourself starring in the next apnea horror video.