The more attention you pay to the breath, the more you realize what it can do for you. You can think of whatever tension or tightness or heaviness there is as dissolving away as you breathe out.

"The more attention you pay to the breath, the more you realize what it can do for you. For most people the breath just keeps them alive, that’s all. But if you pay attention to how the breath feels in the body, you begin to realize that you can breathe in a way that feels good in the stomach, feels good in the chest. This is good for the different organs in your body. Breathe in a way that your shoulders don’t tense up as you breathe in, and you’re not holding on to tension in your shoulders as you breathe out. You can think of whatever tension or tightness or heaviness there is as dissolving away as you breathe out.

And you can think of the breathing as a whole-body process. When the texts talk about the breath, it means any sensation of energy, movement, or aliveness in the body. Parts of the breath energy in the body feel still; other parts move. But if you think of them as all being breath, then you don’t create divisions in the body, as when you think of one part of the body being a solid part that pulls the breath in, pushes it out. Instead, thing of the whole body as breathing energy: breath breathing breath. It’s all connected. It’s all coordinated. It’s all on good terms.

When you get a sense of the breathing like this, see how long you can maintain it. Make it a game. As you maintain it, your mindfulness gets strengthened. Your alertness gets sharper. You become more and more sensitive to what you’re doing, and how the results of what you’re doing appear immediately in the breath. The more attention you pay to this, the more you see."

~ Thanissaro Bhikkhu "An Hour of Bliss"