When you inhale, you are taking the strength from God. When you exhale, it represents the service you are giving to the world.
Source, in full
AS quoted in Healthiest You Ever : 365 Ways to Lose Weight, Build Strength, Boost Your BMI, Lower Your Blood Pressure, Increase Your Stamina, Improve Your Cholesterol Levels, and Energize from Head to Toe! (18 November 2011), p. 291