Housework may seem like the ultimate romance-killer. But guess what?

A new study shows that for husbands and wives alike, the more housework you do, the more often you are likely to have sex with your spouse.

Earlier studies have hinted at this connection for men; the sight of a husband mopping the floor or doing dishes sparks affection in the hearts of many wives. But the more-housework-equals-more-sex link for wives, documented in a study of 6,877 married couples published online recently in the Journal of Family Issues, is a surprise.

Michael Witte

Scrubbing the floor is no aphrodisiac, and seeing your spouse doing it usually isn't either. "My husband loves doing laundry, yet I don't get any thrill out of his doing it," says Chicago writer Julie Danis. And "I don't think he thinks it's sexy when I go around gathering the detritus of his daily life."

But for some high achievers who take a "work hard, play hard" approach to life, researchers say, working hard in one domain produces more energy for others. The study also found a correlation between hours spent on paid work and the frequency of sex in marriage.

"Rather than compromise their sex life" because of time demands at work or at home, "this group of go-getters seems to make sex a priority," says Constance Gager, lead researcher and an assistant professor of family and child studies at Montclair State University, Montclair, N.J. The study doesn't measure what proportion of spouses fall into this group, but she believes "they are on the leading edge of couples we expect to see more of in the future."

Many husbands and wives I interviewed offered an additional explanation—that housework may be a proxy for a general willingness to invest in shared interests, a symbol of commitment to home and hearth. Perhaps "working on the same task … makes the couple remember why they married—to be on the same team, to build a life," Ms. Danis says.

Tom Doran, a Plymouth, Mich., engineer, says doing housework "promotes friendship and intimacy" for him and his wife, an executive assistant. And John Rogitz, a San Diego attorney who has been married for 30 years, says, "If you're both around doing housework, that also means you are alone together, and in a place where both are relaxed and comfortable." He adds, "It's pretty hard to have sex when you're not together in a place that permits it."

“ Wives in the study spent an average 41.8 hours a week on housework, compared with 23.4 hours for husbands. ”

Another husband, a St. Paul, Minn., accountant who describes himself as happily married for 20 years, says housework reflects a deeper bond. Although he does plenty of housework, "to me it's not the dishes, laundry, vacuuming (or Viagra) that matters," he writes. Sharing chores reflects a "willingness to hold my wife's needs and wants on a par with my own. For us, the key to intimacy is the sharing and minimization of selfishness." His wife, a nurse, agrees, saying that "doing the household chores is certainly part of the sharing."

It's also possible that one reward of doing chores—a serene, well-tended home—can be conducive to intimacy. Tracy Evans, New York, says she and her husband "definitely can relax better if the house is clean," she says—to a point.

But plunging too deeply into chores also can have the opposite effect, she says, if it is linked to "this perfectionistic type of thing where you want to get everything done"—for example, deciding you can't rest until your entire spice rack is in alphabetical order. "Before you know it, it's one in the morning and you haven't spent any time with your spouse," Ms. Evans says. Researchers didn't explore whether housework reached a point of diminishing returns—where time on chores expanded so much that it choked off intimacy.

One might suspect that the housework-sex connection was related to couples' views of appropriate gender roles. A wife who embraces a traditional female role, for example, might tend to regard both doing lots of housework and having frequent marital relations as part of her responsibilities.

But Dr. Gager and her co-author, Scott Yabiku, associate professor of sociology at Arizona State University, Tempe, controlled the results for "gender ideology" and found the housework-sex link remained true, regardless of people's views on roles. Results from the data, taken from the National Survey of Families and Households, were controlled for age, health, duration of couple's relationship, religion, income, education and marital satisfaction.

The study defined housework as nine chores: cleaning, preparing meals, washing dishes, washing and ironing clothes, driving family members around, shopping, yard work, maintaining cars and paying bills. Wives in the study spent an average 41.8 hours a week on these tasks, compared with 23.4 hours for husbands—a split that is fairly typical, and often regarded by wives as unfair. However, the effects of any fairness concerns among wives weren't measured in this study.

Outside the home, husbands spent an average 33.8 hours a week on paid work, compared with 19.7 hours for wives. Couples reported having sex 82.7 times a year on average, or 1.6 times a week, about the same as in other studies.

After a long national decline in time spent on housework, the study joins a growing body of research on how chores shape the dynamics of marriage. A survey of 2,020 U.S. adults placed "sharing household chores" as the third most important factor in a successful marriage, behind faithfulness and a happy sexual relationship, says the nonprofit Pew Research Center. That's a sharp increase; 72% of respondents gave high importance to housework, up from 47% in a comparable study in 1990. In respondents' minds, housework outranked even such necessities as adequate income and good housing, Pew says.

A 2003 study by Scott Coltrane, a sociology professor at the University of California, Riverside, linked fathers' housework to more feelings of warmth and affection in their wives. And a survey of 288 husbands, reported in Neil Chethik's 2006 book "VoiceMale," linked a wife's satisfaction with the division of household duties with her husband's satisfaction with their sex life.

One husband, Mr. Chethik says in an interview, reported that his wife enjoyed flowers or a candlelit dinner out; but "if he wants to be sure of a romantic evening, he goes for the vacuum cleaner."

Other research supports the "work hard, play hard" thesis. Janet Hyde, a professor of psychology and women's studies at the University of Wisconsin, Madison, has found that it doesn't lead to less intimacy in marriage when wives hold paid jobs.

"Some people are high-energy people, and others are not very high-energy," she says. Those who like juggling a lot of roles are often energized by the process, she says. "Work hard, play hard" may not work for everybody, but there is certainly a group for whom it does work."

That usually requires conscious effort. Mary Miller, a marketing executive, says that while she and her husband talk at home in the evening about making time for each other, "we are often too tired once we finish cleaning up the place," she says. Recently, they have begun planning to reserve down time for themselves, "almost like adding it to the chores," she says.

Could the study spark a national housework craze? Like a number of spouses I interviewed, Lawrence Lamb is skeptical. At home, the Birmingham, Ala., medical-school professor unloads the dishwasher and puts away laundry while his wife, a teacher, does laundry and cooks. "But that has nothing to do with the sex life," he says. For him and his wife, career achievement and the energy and attitudes they bring to their relationship provide more of a spark, he says. The bottom line, he adds: "It's chemistry."

But another married man, a communications manager attending a panel discussion at which the research was mentioned, quickly announced that he was leaving. "Gotta go," he said. "I need to run home and put in a load of laundry."

—Email sue.shellenbarger@wsj.com