Emile Wamsteker, Ringling Brothers Ringling Brothers and Barnum & Bailey's Circus comic Bello Nock moves the minute hand forward on a giant-sized clock affixed to the side of Madison Square Garden in New York, yesterday. Nock performed the stunt to promote his new daredevil act called "Bellobration" while reminding onlookers to set their clocks one hour forward tomorrow for daylight savings time. The Empire State Building is seen at left. Click photo for larger image. For more information visit: webexhibits.org people.howstuffworks.com tech.yahoo.com/blogs/raskin www.seizethedaylight.com/ www.sunrisesunset.com/

Some will cheer and others will jeer tomorrow as daylight-saving time starts three weeks earlier than last year.

DST begins at 2 a.m. tomorrow after which clocks -- whether they're on wrists, walls, VCRs, DVRs, PCs or PDAs -- should be turned forward one hour.

Thanks to a provision in the Energy Policy Act of 2005, we're gaining three weeks of evening daylight in the spring and an extra week in the fall. Clocks now will switch back the first Sunday in November.

The change is likely to kick-start outdoor exercise programs earlier in the season and reduce crime and traffic accidents. However, it also could disrupt some time-sensitive computer systems and cost U.S. airlines profits because they'll be operating out of sync with European airports for a couple weeks.

Many people love the idea of daylight-saving time because it will give them more daylight in the evenings for activities. Others hate the darker mornings and feel discombobulated because their body rhythms are disrupted when they lose an hour of sleep.

"I was standing in Kmart and flipping through my monthly planner and almost went 'whoo-hoo' when I saw it was going to come earlier this year," says Laura Lind, 38, of Squirrel Hill. "The feeling of having longer daylight really makes a difference to me. I feel much happier."

Thomas Ziemba, a former Aliquippa-area native who now lives in Chesapeake, Va., isn't looking forward to it.

"I sure would like to know what boneheaded politician came up with this dopey idea," he says. "There was nothing wrong with the way daylight savings was set before."

A couple of Congressmen -- Rep. Fred Upton, R-Mich., and Rep. Edward Markey, D-Mass. -- sponsored the provision of the Energy Policy Act of 2005 that extends daylight-saving time.

Mr. Ziemba doesn't mind having more daylight in the evening to take a nice run after work, but says the dark mornings are dangerous, especially for schoolchildren crossing the street.

Studies have shown that daylight-saving time saves energy and that's the historic reason it was instituted and why it's being extended now, says David Prerau, author of "Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time."

When people conduct more of their daily living -- work and play -- in the light of day, they tend to use less energy.

There have been episodes in the past -- during World War I, World War II and for 1 1/2 years in 1974-75 -- that daylight-saving was year-round to conserve energy.

"It's possible that the energy savings we had before won't be found this time," Mr. Prerau says.

Two University of California at Berkeley economists doubt the United States will save energy. They found that electricity use didn't drop when daylight-saving time was extended in Australia for the 2000 Sydney Olympics. Increased energy use in the darker mornings offset reduced energy use in the evenings, they said.

So, as part of the Energy Policy Act of 2005, the Department of Energy will study the energy impact of extending daylight-saving time.

DST is credited not only with saving energy but decreasing crime, accidents and fatalities. Dark mornings may cause a slight increase in morning accidents, but the drop in evening accidents and fatalities will more than offset any rise in morning accidents, Mr. Prerau says.

That's why Alex Kramer, who is visually impaired and finds it difficult to see well enough to drive when it's dark, welcomes more evening daylight. "It will give me more independence and freedom in being out and about," says Mr. Kramer, 77, of Moon, who regularly drives to Sewickley to see his daughter and her family. "This will enable me to visit longer without worrying about turning into a pumpkin."

Colleen Kerno, too, welcomes the extension of daylight-saving time. She gets what she calls "the gloomies" in winter.

"Now, I get up at 5:30 every morning and I hit the snooze about 10 times," says Ms. Kerno, 61, of Mount Washington. "When it's sunny, I get up quicker."The time change is a signal that spring is around the corner.

"I've been hearing from members throughout ... the past two weeks that they're really ready to get outside and become more active," says Mary Vogliano, who leads several Weight Watchers groups in Allegheny County. "Springing forward signals a change and gives [people] an opportunity to rejuvenate their commitment to their fitness goals and their weight loss goals in general."

Rob Walters, program manager with Venture Outdoors, says even with the increased daylight in the evenings, the weather will still be a bit cold at first. Most of the outdoor activities take off in May.

For Orthodox Jews, the change will push back evening prayers at sunset.

Timothy H. Monk, Ph.D., a University of Pittsburgh Medical Center psychiatry professor, isn't certain the time change is necessarily a good thing.

"Basically, what we're doing is giving the whole population jet lag, a little jet lag, but jet lag nonetheless," says Dr. Monk, who has done research on the human biological clock and what happens when that clock is disrupted.

For at least a week after the time change, a larger proportion of people need an alarm clock to wake up in the morning, more people are in a worse mood and more people feel less alert, his research has shown.

"The other disadvantage is, we're not changing at the same time as the rest of the world," Dr. Monk says.

That's proven troublesome to U.S. airlines that worry the DST extension will cost them profits. U.S. airlines have negotiated fairly rigid landing and take-off times in foreign airports and Europe doesn't switch to daylight-saving time until the last Sunday in March, Mr. Prerau says.

"So, if we have DST and they don't have it in Europe and [U.S. airlines are] not able to change their take-off times" that will disrupt the entire scheduling system for domestic flights to meet international flights and have those nice connections, he says.

U.S. airlines could be forced to offer less convenient connecting flights that would put them at a competitive disadvantage with European and Asian airlines. No flights out of Pittsburgh fly directly to Europe.

Other fallout may come courtesy of all the time-dependent machines people have, from computers to PDAs and cell phones to TiVO, most will need an adjustment -- even some manufactured after 2005. European manufacturers never accounted for the time change, while others simply forgot.

"It has this ripple effect, and people aren't aware of how many things we use that are time-dependent to some degree," said Robin Raskin, a Yahoo! Tech adviser. "My guess is it's not going to be the end of the world, but it's going to create some problems, more on a corporate level than a personal level."

People should visit the manufacturer's Web site for their electronic and computer equipment to find the necessary patches.

As a precaution, people also should print out their calendars today and keep a manual version, sending verifications of future meeting times the day before, and making sure any synced device uses an override with the proper time, she says.

This could all be avoided if the United States observed daylight-saving time year-round, says Joe Renckly, who hates reprogramming his internal and external clocks twice a year.

"We'll save some energy and there will be less anxiety," said Mr. Renckly, 56, of East Allegheny. "And the world will be a happier, peaceful and more restful place."