My great-grandma had obvious biceps. I doubt she lifted a weight in her whole life, but she cooked without electric beaters for a large portion of her life. At a time she washed clothes by hand. Basic daily chores were hard work. Machines have really made daily life much easier, but it also enables us to sit more and be less active. Computers and televisions increase inactivity too. So nowadays we have to make time for exercise. Our daily chores no longer really count. You can even mow the lawn sitting down now.
So next time you feel like you don’t have time to fit in exercise. Think about how little time you’d have if you had to wash all the dishes and clothes by hand and then pull all your rugs outside and beat them to get the dirt and dust out.