It is the news most women today do not want to hear - their husbands relax best when their wives are doing the chores.
Researchers came to the conclusion after spending two years studying 30 couples in Los Angeles testing their stress levels during the week and at the weekend.
Unsurprisingly they found wives relax when their husbands are helping out with the washing, cooking and cleaning, but men are most at ease when they have their feet up and their other halves are on domestic duty.
The study, published in the current issue in the Journal of Family Psychology, also found wives generally spend more of their 'free' time at home doing housework, while their other halves spend more time indulging in their own hobbies.
It confirms the traditional stereotype that women work harder for the household than men - often doing twice as much housework as their husbands.
Earlier this month researchers from the University of South Florida found that men react aggressively if they feel their masculinity is being threatened.
After doing tasks traditionally associated with women, like cleaning or housework, men will deliberately behave in a more macho way to restore their self-esteem, they found.
The Center for the Everyday Lives of Families at the University of California in Los Angeles conducted this latest research between 2004 and 2006.
They surveyed dual-earning couples in their early 40s who had been married for about 13 years.
They all had at least one child aged between eight and 10, many with three.
Their saliva was tested and researchers tracked their activities at 10 minute intervals on two weekdays and two weekend days to measure levels of stress hormone cortisol.
They recorded more than 5,500 unique entries about a couples' activities, classifying them in 13 different categories, and found men had lower stress levels when they had free time and their wives were doing household chores.
The hormone can affect sleep, weight and immune resistance if it is too high.
Anthropologist Elinor Ochs told USA Today: 'What we did was videotape from morning to night. We looked at where family members were every 10 minutes — who was with them and what they were doing. We did intensive interviews about their health and well being.'
She said previous research showed men tend to spend time alone after work to wind down from the day, whilst women tend to focus on childcare and then housework when they are alone.
Lead author Darby Saxbe said men might find it quite rejuvenating relaxing when they know someone else is doing the work.