Well, I guess it’s good news for those of us who get our exercise this way (when I actually do it):

The research on more than 200,000 women from nine European countries found doing household chores was far more cancer protective than playing sport.
Dusting, mopping and vacuuming was also better than having a physical job.
The women in the Cancer Research UK-funded study spent an average of 16 to 17 hours a week cooking, cleaning and doing the washing.
Experts have long known that physical exercise can reduce the risk of breast cancer, probably through hormonal and metabolic changes.
But it has been less clear how much and what types of exercise are necessary for this risk reduction.
[…]
Out of all of the activities, only housework significantly reduced the risk of both pre- and post-menopausal women getting the disease.
Housework cut breast cancer risk by 30% among the pre-menopausal women and 20% among the post-menopausal women.
The women were studied over an average of 6.4 years, during which time there were 3,423 cases of breast cancer.

Well, I think that this is even more motivation for me to get in shape.
(via)
BTW, losing weight is the number one New Year’s resolution among women. Speaking of New Year’s resolutions, here is Jonathan Edward’s list and here is Douglas Groothuis’ list of 15 “refusals” (via).