"I feel compelled to be constantly in touch with my work, including weekends and holidays, but you learn to live with this situation," said Barbero, the chief technology officer at Spanish and Portuguese-language media group Prisa (PRS.MC).

"When you are part of the most important decision-making bodies of a company, there are no limits on dedication. I have little time for family or social activities."

In recent years, many companies on Wall Street and beyond have embraced the mantra of flexible hours and work-life balance. Read any image-building column written by a top executive, and he or she is likely to stress the importance of getting to a child's soccer game or concert.

The idea of flexibility and fewer total hours on the job has clear popular appeal. The 2007 book "The 4-Hour Workweek: Escape 9-5, Live Anywhere, and Join the New Rich," for example, became a huge best seller.

But tales of short hours and relaxed work environments do not mesh with reality for many senior managers. The problem is that modern communications may allow less time in the office, but compel them to work around the clock, according to 10 executives in six countries interviewed as part of a larger Harvard Business School survey.

Some grimly predict that those seeking to get to or stay in the executive suite will have to be plugged in almost constantly.

Without a company publicist to cast a positive spin on corporate life, the executives spoke bluntly about how technology increasingly captures their off hours and fills their lives with stress. All subsequently gave their consent for Reuters to reprint their remarks, and two, including Barbero, agreed to have their names published.

"There is no getting away, not at all, no, not when you are in a higher position," said Susanne Meinl, director of human resources at marketing firm Design Hotels AG (LBAG.F) in Germany. "A call center agent, they just leave the office and go home and not bother about anything, but if you have a position with a lot of responsibility ... 24/7 availability is a given, has always been and will always be."

One Canadian executive described what some might see as a dream job: luxurious life on a Caribbean island, huge paycheck, high profile as a hedge fund manager. It wasn't.

"In my 30s I worked 80 hours, 90 hours," said the executive, who is now chief financial officer of a publicly traded Canadian company. "I had a young child and dedicated all of my time to my career, and this clearly was not a good way of living. And as a result of that, I went through a divorce."

Of course, earning big money and being part of the 1 percent rather than the 99 percent does give the executives more choices, particularly concerning early retirement. "For me the reward of this lifestyle is that I'll be able to alter my lifestyle much earlier," said a top official at a California biotechnology company.

One executive said his wife really enjoyed the upscale living his salary provided for the family, even if he was not around that much.

To be sure, all of those interviewed said they found their jobs interesting, and Design Hotels' Meinl drew a stark contrast between the executive suite and a menial position elsewhere. Cashiers in a supermarket "will not burn out in the way someone burns out like me. I mean, they are bored and not appreciated."

One top international airline executive said a tragedy -- the loss of a child in the fifth month of his wife's pregnancy -- reinforced the need to balance work and home.

"The always-online kind of approach is, from my point of view, close to noise, close to pollution," he said. "In a top management job, how can you work strategically smart if you are embedded in noise?"

An executive who is afraid to delegate, he added, "should be prepared to get emails at night."

For many executives, though, balance is elusive, and their jobs have become an endurance test.

A CEO of another biotech company says he works 11 or 12 hours a day and is always on call. "Sometimes I stop and think whether or not I can continue with what I am doing with the level of stress that I have and then what always surprises me is that I am able to accommodate it and go to the next level of more stress," he said.

He now regrets that he was not around much when his two teenage children were smaller, so he wants to do better with his 6-year-old.

"All of a sudden I have turned around and my kids are no longer living at home, they are in college and then I have a little one at home," he said.

Why then does he devote so much time and effort to his job?

"It's not an objective; it is not something I want to do," he said. "I think that people today expect that you are available and going to be available at all times, and if you don't return an email within an hour, or even minutes, then people think that you are not paying attention to them.

"I feel like if I take a vacation, it is not going to be a vacation because I am going to be working all the time."

The balance shifts even more toward the company and away from "my time" as a manager gets higher up the ladder, the executives say. If anything, most interviewed expected demands on their time to increase in the years to come.

"Technology has created an expectation that you are connected," said Meinl, who enjoys yoga in her free time. "With the economy, there is definitely more expectation for employees to deliver now ... Work-life balance will become harder."

Those who use personal time for work will be the great economic winners as technology advances, the California biotech executive said.

"I hate to say it," he said, "but I think the technology is just enabling the people who are really hungry for success to climb quicker, further, and your middle America, your blue-collar worker, (for whom) technology is a convenience to just enjoy life a little bit better, is not going to benefit from it economically.

"The problem is just going to get worse and worse, where you have got a small group of people who are just leveraging technology to be 24/7, you know, anywhere on the planet and that will make them more productive people, but it will separate them even further from the rest of society.

"I can see a scenario where you have people who have every five minutes of their lives planned out and technology on the fly and data coming to them left and right, and I can see where most people would look at that and say 'Oh my God, that's awful.'"

(Adam Tanner is a Reuters correspondent on a 2011-12 Nieman fellowship at Harvard.)

(Editing by Martin Howell and Lisa Von Ahn)

• A Permanent Economic Emergency