I can most relate with your comment about parenting (older children) is more emotionally exhausting vs. physically.  Although our three children are all under 5 years old (and a 4th on the way) I speculate, from a father's perspective that we have experienced more emotional stress than physical already.  We are exhausted daily and particularly when the kids come back from an over-night at a grandparents house.  We simply do the best we can.