Regular meditation and relaxation have been shown to boost genes that encourage efficient mitochondrial function (i.e. the energy centres of the cell). Conversely, one could also reasonably conclude that stress would make mitochondria function inefficiently, in addition to the other raft of depleting factors that stress may induce.
Moral of the story: de-stress and promote deep relaxation. It will benefit your energy, sleep, detoxification and general physical and psychical regulation.