Lots of things change our biochemistry.  Air, water, smoke, coffee, prescription drugs, etc.  But, the remarkable thing is that our biochemistry also changes in response to our envioronment including sounds and music, cramped versus open spaces, lightness and darkness.  This time of year people in countries in the Northern Hemisphere suffer from seasonal affect disorder -- because their mood (e.g., caused by biochemistry) changes in response to the reduced hours of light during the day and increased inclimate weather.  Understanding all of that and adopting a holistic view of your body and controlling it is the challenge. 

You are completely right, however.  Movement, exercise, quality sleep, and eating healthy foods are all ways to control your biochemistry in a positive way and maintain an upbeat and positive mood.  In addition, meditation, prayer, yoga and other introspective practices also provide greater/deeper insights -- perhaps even insights into the soul and Nirvana.