Engaging in sedentary work immediately after a heavy meal without physical exercise checks the free flow of thought and diminishes communicative force.

Original passage

Many writers and speakers fail here. After eating heartily, they give themselves to sedentary occupations, reading, study, or writing, allowing no time for physical exercise. As a consequence the free flow of thought and words is checked. They cannot write or speak with the force and intensity necessary in order to reach the heart; their efforts are tame and fruitless.