What do CFOs and godfather of soul James Brown have in common? Reportedly, they are hardest working “men” in their respective businesses. At least that’s the conclusion of a new study that interviewed 60 CFOs from the largest companies in the U.S. and Europe.

Since passage of the Sarbanes-Oxley Act (Sarbox) in 2002, which heaps more accountability on CFOs than other executives, and the spate of accounting scandals that sent companies into bankruptcy and furious investors into shareholder lawsuits, the job description of CFOs has changed. But not all incumbents like their new role. “Hair, golf, tennis — all gone,” quipped one CFO, when asked whether his new duties are taking a personal toll on his work/life balance.

Another, more stoic finance chief, declared that “everything is fine,” when asked the same question — and then proceeded to recount his typical 70 hour work week, four hours of weekend work, and vacationing with the Blackberry turned on.

The personal strain on CFOs is palpable now that the scope and complexity of their responsibilities has mushroomed, concludes a joint study released last week by consultancy Mercer Inc. and executive search firm Russell Reynolds Associates. “We’ve reached a point where the scope of the CFOs job cannot be widened,” opines Mercer Oliver Wyman executive director Charles Bralver. “We just can’t toss any more on their shoulders and expect them to do a good job.” Mercer Oliver Wyman is part of Mercer.

In the report, CFOs admit that “enjoyable” business activities, such as meeting peers or participating in industry working groups have fallen by the wayside. Unfortunately, they’ve been replaced by oppressive travel schedules and certifying stacks of financial documents as CFOs split their time between being a business partner to the chief executive, and a fiduciary to the board, explains Chris Langhoff, executive director of Russell Reynolds.

The dual role that CFOs play is not a new one, but the degree of scrutiny surrounding that role has been elevated, adds Bralver. Nevertheless, the study found that CFOs are clear about their priorities: Their first obligation is to get the numbers right. Contributing to their company’s commercial and strategic agenda comes second, now that accounting and financial reporting has become more of a “value-added” function. During the first year of Sarbox implementation, “there wasn’t a lot of business partnerships happening,” noted one CFO who was interviewed for the study.

Once the numbers are bullet proof, CFOs have a lot of explaining to do, says the study. The universe of stakeholders has grown, and they are craving more detailed information. For example, board members require more handholding than before. Directors want CFOs to conduct informal one-on-one meetings outside of regular board meetings, as well as training on specific topics.

In addition, CFOs are spending longer hours tailoring presentations to board-level audiences. Instead of inundating the board with financial statements and internal documents, for examples, more CFOs are sifting through the material and presenting so board members are “comfortable,” with the details, says the report.

Also vying for the CFOs time are new investor classes — such as hedge funds — as well as bond analysts and other stakeholders with long-term interests in a company. In the wake of a record number of credit rating downgrades and bond defaults over the last few years, bond analysts are especially interested in hearing directly from the CFO about a company’s financial fundamentals and attendant health.

“The CFO is more active than he or she was five years ago,” asserts Langhoff, and to handle the heavier workload, he says CFOs have been relying on “super controllers.” These caped accountants, sometimes called the chief accounting officer, oversee the corporate accounting and financial reporting functions, so that a CFO can focus on more strategic or operational duties, such as mergers and acquisitions, capital raising and deployment, treasury management, and sometimes information technology, human resources, and supply chain issues.

Increasingly, CFOs bring their controllers with them when they change jobs, says Langhoff. If not, they are actively searching for an executive to step into the super controller role to help share the CFO burden. Indeed, hiring a super controller may be one way to retain a current CFO, or attract a new one.

Even though the CFO position remains a coveted post, retention may be a bigger issue that expected going forward. Indeed, turnover at the CFO spot is up, says another Russell Reynolds survey released last year. According to the findings, 4.7 percent of the CFOs at Fortune 500 companies left their jobs in 2004, compared with only 3.5 percent in 2003. “If I were a younger financial director coming up through the ranks,” posited one UK executive, “the thought of managing a business’s finance in the current governance environment would not be appealing.”

In fact, some CFOs from the joint study worry that the pipeline for young finance chiefs is drying up because candidates are deterred by the professional and personal demands of the job. “Young guns used to say ‘I want your job,'” comments another CFO. But now all he hears is that the CFO job has “Too much stress,” and “Life is too short.”

CFO burnout is not the only reason executives leave their post, however. Some CFOs are kicked upstairs. Another survey released by Russell Reynolds last year showed that one-third of theFortune 500 CFOs that left their positions in 2004 did so because they were promoted to CEO, chairman or became a CFO of a larger company.

In addition, the second study found that having a financial background seemed increasingly useful in landing a CEO position, especially in the United States. For example, 14 percent of the Fortune 100 CEOs were former CFOs. In the UK, a similar trend prevailed, however most of those CFOs were named chairman.

There’s one other silver lining — albeit this one has been widely reported. CFO pay is rising as fast as the workload is ballooning. The average overall compensation package for CFOs — including salary, bonus, and stock and option grants — was $2.2 million in 2004, according to the Mercer 350 salary survey, which bases its calculations on data collected from companies with over $1 billion in revenues. Since 1997, when the average compensation package was $1.34 million, CFO compensation has been growing at a 7.4 percent compound annual rate.

During that period, base salaries only increased at a 3.8 percent rate, and currently hover around $500,000 annually. As expected, stock and option grants accounted for most of the compensation, and compensation growth, averaging about $1 million in 2004, and growing at an 8.8 percent.

So, while the demands of a CFOs have increased, so has the rewards. And that, as James Brown might say, “feels good.”