New York, April 9 (IANS): At times, even too much of a good thing just might be bad. Spending time with your grand kids would help you stay sharp, only if you could limit the activity to once a week, a study reveals.

Taking care of grandchildren five days a week or more had some negative effects on tests of mental sharpness, the study found.

“We know that older women who are socially engaged have better cognitive function and a lower risk of developing dementia later but too much of a good thing just might be bad,” said Margery Gass, executive director, The North American Menopause Society (NAMS).

The study involved 186 Australian women, ages 57 to 68, took three different tests of mental sharpness.

It noted whether they thought their own children had been particularly demanding of them in the last year.

Among 120 grandmothers, those who spent one day a week taking care of grandchildren performed best on two of the three tests.

But those taking care of grandchildren for five or more days a week did significantly worse on one of the tests, which assesses working memory and mental processing speed, said the study published in the journal Menopause.