don't sit up during your confinement, coz your uterus and your back bone still weak after trauma of giving birth... if you want to be in shape you can wear the corset lingerie right after give birth so ur tummy not buldging.
and can start exercise like running after 3-4 mth..and if you had ceaserean might be longer i tink..can consult w/ ur doc? coz i was having normal delivery ..so 3mth-4mth can start jogging.