NEW YORK — The young and ambitious used to be told "Go West, young man." Now it could be "go weekend."

Odd shifts — weekends, nights and overnights — are no longer limited to police, firefighters, medical workers and a handful of other jobs. As the U.S. economy becomes increasingly connected to the global one, and as workers seek new ways to cope with the demands of education, child care and career advancement, a whole new generation is taking a look at the dark side.

"Best thing about it is grocery shopping on Tuesday instead of Saturday," said Margy Schilling, a nurse at St. Joseph's Regional Medical Center in Paterson, N.J., who has worked odd shifts for more than 20 years.

Unusual working hours can offer serious benefits, especially for hard-working twenty-somethings and for parents.

"Young people want to sleep until 2 p.m. anyway," said Schilling, a mother of three.

"When the kids were in school, they went to school and I went to bed. When they got out, I was getting up. I didn't miss much of their lives."

Nearly 22 million Americans — about 18 percent of those with jobs — work nights and weekends, according to 2004 figures from the U.S. Bureau of Labor Statistics. Men worked alternative shifts more than women, and blacks were more likely to work odd hours than whites, Hispanics or Asians. People with part-time jobs worked more nights or weekends than those with full-time jobs.

Some occupations require more alternative shifts than others. Half of those working full-time in the security field (police, firefighters, guards) worked nights, overnights and weekends, along with 40 percent of the food industry and 38 percent of tourism-related jobs, according to the labor bureau.

"If you work at a hotel, you know that hospitality is a 24-7 job. You are going to have to work some work nights and weekends," said Kendra Walker, spokeswoman for the Hilton family of hotels, which employs about 90,000 workers in more than 2,300 U.S. hotels.

"Most people on the night shift have requested it for one reason or another," she added, citing students who need to take daytime classes, people working several jobs or parents with child care issues.

Employees also may opt for night or weekend shifts because they want to work at a certain hotel where no day jobs are open, she said.

And working unusual hours can allow new employees to bring their skills up to speed as they gain some seniority.

"Managing the front desk is quieter in the evening," Walker noted. "They need to warm up to handle the more hectic pace of the day."

Night shift experience is essential to advance in some job categories, such as front desk employees and security experts, she said. Those involved with event planning and catering know that weekends are going to be full of conferences and weddings.

Other industries that rely heavily on alternative shifts include transportation, shipping, mining, utilities, health care and journalism. And don't forget creative deadline types: Video game programmers, graphic artists and advertising whiz-kids are famous for pulling more overnighters than the college crowd.

Even traditional employers like law firms and banks may have graveyard shifts for support workers. Mark Hubble, 43, works a 12.5-hour overnight shift three days a week in Manhattan editing documents for Davis, Polk & Wardwell, an international law firm.

The father of a 1-year-old girl, Hubble is among many new parents seeking more quality time with their kids.

"This can work," he said. "I've been able to spend a lot more time with Lucy than I would if I had been 9-to-5."

And the arrangement saves money: He hasn't had to pay yet for childcare, even though his wife, Marnie, works part-time.

Delta flight attendant Lesley Larson has worked odd shifts for 18 years, but really began to appreciate the option when her daughter was born four years ago.

"I try to limit the time my daughter has to spend at a baby sitter," she explained. "I mostly work around my husband's somewhat normal schedule."

Other young parents plan on checking out the night shift as soon as they can master the chaos of their day. Gina Caroddo, a freelance writer in Brooklyn with a 3-month-old son, often used to work late into the night anyway meeting deadlines.

"I would love to work nights," she said. "A happy parent will be a better parent, and if that means working, then you should do it."