Isn't it amazing how rejuvenated we feel when we wake up from a good night's sleep? No matter how tired, jaded or emotionally drained we are the night before?
His Holiness Bhakti Caru Swami once explained in a lecture that the soul retreats into the core of the heart and spends time with the Supersoul when we sleep.
Recently I asked His Holiness Sacinandana Swami about this, who clarified: "It's unconscious association. When we chant, we associate with Krishna consciously."
Maybe that's why the Six Goswamis didn't need much sleep–blissed out and rejuvenated by tapping into the Fountain of Youth, Sri Nama Prabhu.