Do you take your kids out everyday?

I have two toddlers, a three yr old and a 2 yr old and I make sure we go somewhere most days, the eldest goes to nursery in the mornings during the week. However, on a Sunday I like a good loaf and just want to schlep round the house in my PJ's eating and watching TV. Is it unhealthy to keep them in one day a week watching kids TV and playing indoors, am I affecting some fundamental part of their development??