Actually, not so. This was the whole purpose of the parable of the prodigal son. He was in good standing with his father, he left his father, and when he came back to the father, what did the father say? "My son was dead but now he is alive." He didn't die physically, but spiritually. ("God is the God of the living, not the dead.")
When we leave the Father, we are spiritually dead.
Jesus said "I tell you the truth, unless you eat of the flesh of the Son of Man (spiritually), and drink His blood, you have no life in you."
Does our heart beat once? No- it beats continuously to supply the whole body with blood- and the Bible says the life is in the blood.
It's not enough to get baptized into Christ, you have to continuously partake of the Lords Supper, upon the first day of the week, in the assembly of the church.
If you leave Christ's body (His church), then you leave Christ, and His blood.
If you go back to living in the world, sinning purposely, "there no longer remains a sacrifice for your sins." And "no longer" means there once did, but no longer does. (Hebrews 10:26)