LONDON – Volkswagen turns off some employees’ email 30 minutes after their shifts end. Goldman Sachs is urging junior staff members to take weekends off. BMW is planning new rules that will keep workers from being contacted after hours.

This surge in corporate beneficence isn’t an indication that employers are becoming kinder and gentler: It’s about the bottom line. After years in which the ease of instant communication with email and smartphones allowed bosses to place greater and greater demands on white-collar workers, some companies are beginning to set limits, recognizing that successful employees must be able to escape from work.

“Industry is now responding,” said Cary Cooper, a professor of organizational psychology and health at Lancaster University, who says the imperative to be constantly reachable by iPhone or tablet is taking a toll on the work delivered at the office. “Employees are turning up, but they’re not delivering anything.”

After seeing colleagues lose their jobs during the Great Recession, workers are more inclined to come in to work, even when sick, surveys show. After hours, physical presence is replaced by the next best thing – a virtual one. Many employees fear switching off, instead deciding to work on vacation, during dinner and in bed with the help of smartphones, laptops and tablet computers.

People also have more data than ever to process – whether they ask for it or not. Information overload cost American businesses just under $1 trillion in employee time lost to needless emails and other distractions in 2010, according to Jonathan Spira, chief analyst of the New York research firm, Basex.

The cost of replacing employees who leave in search of better work conditions is also a concern. A study from the Center for American Progress put the cost of turnover at just more than a fifth of the employee’s salary for people making up to $75,000 a year. That goes up exponentially for top managers, with turnover costs as high as 213 percent of salary for very highly paid positions.

After worrying about trimming staff-member numbers during the recession, employers are focusing on how to keep those who are left from burning out.

Lowering stress

One strategy, which Goldman Sachs has been trying, is to make people feel less at risk in their jobs. That’s not easy in most companies, much less so in investment banking, infamous for its competitive environment and grueling work hours.

To keep junior analysts from burning out in the attempt to prove their worth, the bank has decided to start hiring first-year analysts as permanent employees, instead of taking them on as contract workers. It is also encouraging them to not work weekends.

“The goal is for our analysts to want to be here for a career,” said David Solomon, global head of investment banking at Goldman Sachs. “This is a marathon, not a sprint.”

Information overload

Though technology has helped boost worker productivity during the last few decades, it has come with related costs, such as stress.

Technology, for example, is eliminating the downtime or slack that used to be built into the day – such as the time one took going to the library to do research that can now be completed online, says Edward Tenner, author of Why Things Bite Back: Technology and the Revenge of Unintended Consequences. Those minutes used to act as a buffer that prevented people from working constantly.

Though physical exhaustion in traditional enterprises was bad, conflicting mental demands can be more problematic, Tenner says, particularly in the United States, where professional workers often don’t have union contracts or the same legal overtime protection as hourly workers do.

“So it’s as the Red Queen said in Through the Looking-Glass, it takes all the running you can do to keep in the same place,” Tenner said.

Companies haven’t yet come to grips with how bad it is, said Spira, the analyst. Information overload has decreased people’s ability to manage thoughts and ideas. Fixing it means changing company culture – such as the idea that dozens of people need to be cc-ed on a given email.

“Almost every organization is burying its head in the sand,” said Spira, the author of Overload!: How Too Much Information is Hazardous to Your Organization.

It is hard for a company to control the amount of technology used in the workplace and at home since it is so integral to modern life. Volkswagen addressed the issue in a blunt, if effective, manner – by deactivating some workers’ email accounts once their shifts were over.

Rival BMW plans this week to unveil new rules to foster a management culture that “values the limits of work hours and reachability.” The company declined to offer specifics, insisting that employees should learn the details before the media.

Tougher measures

To get everyone, from intern to CEO, to not overdo it with the work hours, some companies have resorted to bolder measures.

Quirky, a New York based start-up which shepherds inventions to the marketplace, has instituted a “blackout” week once a quarter during which no one except customer-service representatives are allowed to work, lest employees be tempted to check email.

“We all dropped pencils together,” said CEO Ben Kaufman, who figured he could bring the idea of re-invention to his own company. “People were getting burned out. They needed to see other things besides their desk.”