MEN who do more housework get more sex. And women who do more housework get more sex, too. A US study of almost 7000 married couples shows that couples who work hard, play hard.

''Go-getter'' couples who devote lots of time to paid work and household chores still make sex a priority, says the study, published in the Journal of Family Issues.

The study shows that sexual frequency averaged 82.7 times a year, or 1.6 times a week, although there was wide variation. Age and the duration of the relationship dampened sexual frequency, as did being Catholic compared with being Protestant. The presence of small children reduced frequency but older children were positively associated with more frequent sex.

Women on average did 41.8 hours of housework a week, almost twice as much as the men, and 19.7 hours of paid work, bringing their total labour to 61.5 hours compared with 57.1 hours for men.

The more time spent on housework, the more sex the men and women reported.

The study found if slothful women and men - those who did housework for only 16 hours and two hours a week respectively - increased their effort to match the high performers - women who did 68 hours and men 45 hours a week - they could expect to have sex 15 more times a year.

It also works the other way. Barbara Pocock, director of the Centre for Work and Life at the University of South Australia, said Australian working women found resentment over housework killed libido.

''If the resentment factor was high, that's when their sex life was not great. The best sex aid a man could use was a vacuum cleaner.''