Clocking extra hours at the office while juggling family demands takes a toll on the body mass index of individuals in dual-earner families, says a new study co-written by Amit Kramer, a University of Illinois labor and employment relations professor.University of Illinois According to new research co-written by Amit Kramer, an increase in the work or life demands of one spouse is also likely to affect the health outcomes of the other.

“Work and family are important to many people, and most of life is spent meeting the demands and responsibilities of both,” he said. “We also gain meaning and significance from these two domains. As such, it's not surprising that the circumstances and demands of those domains affect an individual’s health, as well as their general well-being. The big question is how much of an impact it has.”

The paper, which was co-written with U. of I. graduate student WonJoon Chung, used a nationally representative sample of more than 4,200 individuals who were part of a dual-earner family between 1994 and 2010 to explore how work and family demands affected an individual’s body mass index.

Although the passage of time has the biggest impact on BMI – on average, individuals get bigger as they get older – the researchers found consistent evidence that the long-term physical health of individuals, as estimated by a change in BMI over time, is negatively affected by an increase in work hours and the birth of each additional child.

“While the effects of work and family demands on BMI are small, they are statistically and practically significant,” Kramer said. “Medical studies have consistently shown that even small changes in BMI have a negative impact on individual health outcomes such as coronary heart disease, diabetes and lung functioning, to name a few.”

Such effects occur when an increase in an individual’s or a spouse’s work hours leave the family with less time to engage in health-promoting behavior such as exercising, eating healthy and sleeping. But it’s also possible that the strain associated with an increased workload is related to increased BMI, Kramer said.

The paper also considered whether the availability of flexible work arrangements had a moderating effect on the relationship between work demands and physical health. The results indicate that flexible work arrangements had no effect on BMI, most likely because reducing one’s BMI requires actual behavioral changes – more sleep and exercise, for example.

But just because flexible work arrangements have no effect on BMI doesn’t mean that employers should scrap the perk, Kramer says.

“Other research shows true flexible work arrangements – ones that give the worker autonomy and flexibility on when, where and how to do the job – have been shown to improve employee well-being as well as business outcomes,” he said. “It’s possible that flexible work arrangements are directly affecting other health-related outcomes that may provide employees with more opportunities for non-work time. That alone can reduce stress and be used to renew one’s energy level.”

What can employers do to help reverse this trend, since it’s as much in their interests to curb future employee health costs as it is for the employee who wishes to be healthy? According to Kramer, employers should know the costs that work and family demands impose on employees as well as the impact it has on their health.

“If employers care about their employees, their insurance costs or other health-related costs such as absenteeism, turnover, job performance and work satisfaction, this should make them think more comprehensively about their employees’ needs and demands,” he said. “It also would help them with creating cost-effective policies to address the needs of their employees not just as individuals, but as members of a family.”

Workers also need to know that their time is finite, and if their spouse is putting in long hours, it’s likely going to affect them, too.

“Interdependencies between family members are important to consider when making work-related decisions, not just family decisions,” Kramer said. “We think about family decisions as interdependent: Should we have another child? Should we send a child to a day care or should one of us stay at home? But we tend to think of work decisions as individuals: Should I work another hour? Ask for this challenging assignment? Decisions that increase or decrease the demands and responsibilities of work or home also have a direct effect on our spouse’s ability to meet work, family and personal needs.”

Workers also need to know that different organizations may offer better work, family and life policies and benefits, Kramer said.

“More and more employees think about work not just in terms of their career but also more holistically, in terms of their success as a family,” he said. “That means their health and well-being greatly depend on this combination of their spouse and their respective workplaces,” he said.

The paper will be published in the Journal of Applied Psychology.