By Dru Sefton,Newhouse News Service

For heavy sleepers, those near-hibernation snoozers, alarm clocks are not just a gentle reminder to awaken at a certain time but a necessity for getting out of bed – period.

They might get more than a chuckle out of products like the Sonic Boom Alarm Clock With Bed Shaker, especially during the dark mornings this time of year.

Yet researchers say even deep-sleeping humans don’t need alarm clocks, that our dependency may actually hinder our intrinsic ability to awaken at a certain time.

Timothy Monk, a professor of psychiatry at University of Pittsburgh Medical Center, studied sleep diaries of 144 men and 122 women and noticed that some 60 percent used an alarm clock or a person to wake them up.

“What was actually quite interesting to me was that 40 percent did not. That’s very good news,” said Monk, who works with the university’s Sleep and Chronobiology Center.

That’s because, he explained, we all have a built-in clock inside our heads. “If everything is running smoothly, that clock should wake us up before we’d need an alarm.”

Monk said this internal clock senses the approaching morning and goes into action. “It’s a bit like starting a car early to warm it up,” he said. “The biological clock says, we’d better switch on this hormone, raise the body temperature, increase the heartbeat – all in anticipation of waking up.”

Proof of this is the phenomenon of awakening just a minute before your alarm is set to jangle.

To ensure the smooth functioning of this internal clock, it’s important to keep a regular routine, get plenty of sleep and stay healthy, Monk said.

But how many of us do that? Cue the alarm clock inventors!

Sonic Alert Inc., in Troy, Mich., touts its flagship product as “a unique clock that is guaranteed to wake up even the heaviest of sleepers.” Users program the Sonic Boom Alarm Clock With Bed Shaker to awaken them using any or all of its features: a loud alarm, flashing lights and a shaking bed.

“I did have one customer in California that it scared the first time they used it,” said Adam Kollin, who developed the clock and heads the company. “They forgot they had it and thought it was an earthquake.”

The clock is sold online (www.sonicalert.com) and through retailers including Sharper Image.

Kollin actually created the Sonic Boom Alarm 30 years ago for his grandmother, who was deaf. Many customers with hearing impairments continue to purchase it.

Adam Hocherman was tackling a different problem when he had the idea for his Neverlate 7-Day Alarm Clock.

“I was an undergrad at Cornell and had a class schedule where I had to wake up early on Monday, Wednesday and Friday but later on Tuesday and Thursday,” said Hocherman, now president of American Innovative in Ithaca, N.Y.

So he created an alarm that could easily be set once a week for different times each day. “I was totally annoyed by having to hold one button while tapping another every day to set the old alarm clocks,” he said.

The Neverlate sells on the company’s Web site (www.americaninnovative.com) as well as at retailers such as Linens ‘n Things.

But Peter Crabb wondered if using alarms makes us reliant on the technology.

“I’d observed that a lot of people had difficulty waking up in the morning, and there seemed to be a dependence on alarm clocks to take care of that problem,” said Crabb, an associate professor of psychology at Pennsylvania State University-Abington.

Crabb studied more than 400 undergraduate students and discovered a correlation between alarm clock use and the inability to rise at a given time.

“What happens in our society is, when kids reach adolescence their parents give them alarm clocks so they don’t have to learn to wake themselves up on time,” Crabb said.

But awakening naturally can be relearned.

Crabb recommended trying a clock with glowing red numbers – “Green is too bright and might keep someone awake.”

Then, before bed, think about awakening at a certain time. Repeat a phrase such as, “I have to wake up at 7. I have to wake up at 7.”

“Just about anybody should be able to master it again,” Crabb said.

Failing that, the hard-to-awaken may look forward to future creative ways to startle themselves from slumber.

On the horizon is the Blowfly Alarm Clock, which launches itself at a preset time and flies around the room, buzzing until it’s caught. That recently won third prize at the 2005 Taiwan International Design Competition for its designer, Ena Macana of Barcelona, Spain.

Or Clocky, developed by Massachusetts Institute of Technology students, which pops off the nightstand and rolls away to hide when its snooze button is pressed.

That design won an Ig Nobel prize, presented annually for weird-yet-wonderful inventions. It has its own Web site, www.clocky.net, where you can sign up to be notified if it’s ever available for purchase.

Dru Sefton can be contacted at dru.sefton@newhouse.com