Where do grandmom's get energy when a grandchild is born

My mom was 59 years old when kutti was born. Not too old, but for some one who's had 5 major surgeries - tough.
She's always been energetic - finishing up her work in a jiffy and multitasking even before the computer world thought about it. Cooking food that normally takes 1 hour for me, (and 2 hours for my MIL;-) would be done in 25 mins.
And in Tamil Nadu, where kutti was born, people have the most funny and impractical customs. They will visit by hordes to see the baby soon after the delivery. We have to provide them with tea or coffee or buttermilk or juice with or without sugar or milk - they will NEVER say don't bother! They know that the family would have been up all night with a colicky baby and would love to get any rest that they can during day time, but will come and gossip for hours together. And of course, they will have to customarily push a dirty 100 rupees note in the baby's hand which naturally curls and holds the note and exclaim that the baby is already holding on to money!
Where my mom got the patience and energy to handle all these people, and take care of me any my baby - I will never know. But here's a big salute to her and her wonderful spirit - I wish my baby girl turns out like her.