Leading a righteous life lends vigor to old age

Psalm 92:12-15

The righteous shall flourish like the palm tree: he shall grow like a cedar in Lebanon. Those that be planted in the house of the Lord shall flourish in the courts of our God. They shall still bring forth fruit in old age; they shall be fat and flourishing; To shew that the Lord is upright: he is my rock, and there is no unrighteousness in him.