Brain workers require a combination of temperate habits, physical exercise, and an active life to maintain vigor and endurance.

Original passage

Ministers, teachers, students, and other brain workers often suffer from illness as the result of severe mental taxation, unrelieved by physical exercise. What these persons need is a more active life. Strictly temperate habits, combined with proper exercise, would ensure both mental and physical vigor, and would give power of endurance to all brain workers.