Keep your wife happy... spend more time at work: Husbands should do longer hours at the office, study says Wives benefit most when husbands work more than 50 hours a week Researchers studied relationships of 4,000 middle-aged men and women Wives whose husbands work long hours 'have enough money for cleaners' They suggested the extra time would allow them opportunity to get fit By Mark Howarth The key to a happy marriage is spending less, not more time with each other, it seems. For if he wants to improve his wife's quality of life, a husband should spend longer hours at the office, researchers claim. The more overtime he does, the healthier she becomes, with wives benefiting most when husbands work more than 50 hours a week. For if he wants to improve his wife's quality of life, a husband should spend longer hours at the office, researchers claim However the study, published in the journal Social Forces, found that men are doomed to the short straw either way. For when wives work long hours, house-husbands" health suffers - because the weight of domestic chores means they do not get enough time to exercise. The US study set out to discover the effect on family life of greater labour market equality between the sexes since the 1970s. Researchers studied the relationships of nearly 4,000 middle-aged men and women between 1979 and 2004. Healthiest were women whose husbands worked more than 50 hours per week, while the lowest scores were for men whose wives worked between 41 and 49 hours. "The greater income brought in by men's longer hours may be protective of women's health," the study said. The more overtime a husband does, the healthier his wife becomes In contrast, men whose wives work moderately long hours are particularly less likely to spend as much time on vigorous exercise or sports, such as running, swimming, or bicycling. The authors, from the Universities of Texas and Indiana, said wives whose husbands work long hours may have enough money to pay cleaners, giving them the time to get fit - but women's wages may not be high enough to afford house-husbands the same luxury. Campaign group Mothers At Home Matter said: "This underlines the true value of the work which women have traditionally done. It remains a huge and all-consuming job. David Cameron has come under pressure to bring in transferable tax allowances that would mean a full-time mother could give her income tax-free allowance to a working father. A limited version for some married couples is due to begin next year, but will be worth only £3.85 a week at most. Analysis has shown the majority of married couples with children who will be helped will benefit by only £1.30 a week. A recent report by the Joseph Rowntree Foundation showed that the traditional family, with stay-at-home mothers and fathers who work, is now more likely to be existing below the poverty line than any other type. In all 10.5 per cent of women now work more than 45 hours a week, up from 9.5 per cent in 2009 - an extra 186,000 people. For men, the figure has risen from 19 per cent to 19.6 per cent. The typical male working week is now 36.8 hours compared with 26.8 for women.