How much cardio exercise is absolutely necessary for optimal health?

Netzer questioned:

I am already fortunate including how I preview, and I am NOT schooling for a marathon or tiresome to loose consequence.

I am only fascinating in optimal affect and endurance, and don’t want to dissipate any extra time doing cardio than is unquestionably necessary. I bring about full time, am a busy mom, and am plotting to be inflicted including another baby this time.

Only the water-resistant – no opinions delight – I call for answers from experts who admit. Thankfulness!