LOS ANGELES — At last, scientists have rigorously proven that men's need to chill with the remote at day's end is a simple matter of maintaining health and ensuring survival. They've also shown that women's health — not to mention happiness — hinges on her male partner helping with the housework.
Researchers came to this conclusion by studying the daily activities of 30 dual-earner couples in Los Angeles over a one-week period. They also tracked the couples' levels of the stress hormone cortisol, which primes the body for physical and mental challenges during the day and recedes at day's end in anticipation of rest and relaxation.
People with chronically high cortisol levels — or whose levels fail to decline in the evening — not only feel stressed but are vulnerable to a wide range of physical and mental illnesses. They even tend to die younger, studies have shown. So linking cortisol levels with married parents' end-of-day activities should reveal a lot about how domestic routines influence health and happiness, the researchers surmised.
All the couples studied had at least one child between ages 8 and 10 living at home, and the median age of the parents was 41. Observers recorded their activities at 10-minute intervals.
The women, on average, spent 30 percent of their evening engaged in housework and about 11 percent on leisure activity. The men, on the other hand, devoted 20 percent of their time to house work and about 19 percent to leisure.
The scientists from the University of Southern California, the University of California, Los Angeles, and Connecticut College found that spending lots of time on household chores at the end of the day kept husbands' and wives' cortisol levels high. No surprise there.
But on closer inspection, they noticed that the married mothers' cortisol declined most steeply when their husbands pitched in with the housework. Unfortunately, the working dads' cortisol wasn't likely to dip unless they spent more evening time relaxing while their wives stayed busy.
"Arguments about who's doing the dishes and who's flipping through channels" have repercussions for the health of both spouses, the researchers wrote in their study, published in the Journal of Family Psychology.
That's especially true for working moms, said Janice Kiecolt-Glaser, an Ohio State University psychologist who studies the effect of relationships on immune system function.
"The second shift is alive and well, and it has a cost for women," she said.