Jon Kabat-Zinn, who has written 10 books on mindfulness and led nearly a hundred retreats, describes meditation as a mental workout.
Jon Kabat-Zinn: The mind wanders away from the breath and then you gently and nonjudgmentally just bring it back.
Anderson Cooper: So it's okay that the mind drifts away but you just bring it back.
Jon Kabat-Zinn: It's the nature of the mind to drift away. The mind is like the Pacific Ocean, it waves. And mindfulness has been shown to drop underneath the waves. If you drop underneath the agitation in the mind, into your breath deep enough calmness, gentle undulations.
See also: "The Newly Mindful Anderson Cooper"