Worrying about insomnia is keeping me up at night. Feel free to worry along: A study released on Monday found that getting too little sleep more than doubles the risk of death. Unfortunately, so does getting too much. It’s enough to drive you to drink, but what? A double espresso or a Lunesta on the rocks? “If you reduce the amount of sleep you normally have to five hours or less, you are twice as likely to die of cardiovascular disease,” the author of the 17-year study, Dr. Francesco Cappuccio, said. “Cardiovascular disease is the commonest killer in Western civilization.”

Gotcha. Dangerous.

“On the other hand,” the University of Warwick epidemiologist continued, “if you increase your amount of sleep to nine hours or more, you are twice as likely to die of non-cardiovascular disease.” Cancer, for instance. Or maybe terminal restfulness.

The working theory is that people who get too little sleep are at greater risk for obesity, hypertension, and Type 2 diabetes — all bad things that can sometimes lead to lights out. As for why too much sleep leads to that same dark night, it may simply be that people who are already sick start sleeping longer. Or not. No one knows.

In any event, Dr. Cappuccio (who is well aware of what spell check does to his name) isn’t taking any chances. He aims for six hours a night — right around the sweet spot of six and a half.

That, at least, is the ideal amount as determined by another recent study, this one of 1.1 million people, conducted at the University of California, Davis. “Increased Death Rate Associated With Sleeping 8 Hours or More,” the abstract announced.

Ah, yes, those lethal eight hours of shuteye.

If that sounds nutty — and an affront to nagging mothers everywhere — just figure that sleep is the new exercise: a once-normal part of life that has now become something to brag about, obsess about, talk to your doctor about, and most of all feel guilty about. Men’s Sleep monthly cannot be far behind (ditto, Every Night With Rachel Ray).

Or, come to think of it, maybe sleep is more like food: Once upon a time food was something you just ate. Now you have to worry about every bite you put into your mouth and assume that if it’s really good, and comforting, and something you loved as a child, it’s probably going to kill you. Just like a good night’s sleep.

“Sleep is the one thing that we invest more time in on a daily basis that affects our health more than anything else,” a doctor at Northwestern’s Feinberg School of Medicine, David Donnersberger, said in cautionary tones. “You might be on a treadmill for an hour, but you’re sleeping for eight.” Do it right or else.

His advice is to practice “sleep hygiene,” the new catchphrase for proper go-to-sleep protocol:Climb into bed and do only bed-specific things there. You know what they are. They do not include a laptop or a bag of potato chips (usually). Once relaxed and drowsy, proceed to what once comes naturally — or did, a long time ago, before people started studying sleep and telling you you might die if you do it wrong.

Sweet dreams!

But not more than 6 1 /2 hours’ worth.