Body
Body is the complex physical structure which consists of different functioning systems like Skeletal, Muscular, Cardiovascular, Respiratory, Nervous, Digestive, Reproductive etc. Body is the vehicle through which we maneuver into the world with our thoughts and ideas. We perceive the world through our sense organs and use our brain to think and make decisions. In order to maintain and grow healthy, body needs proper diet, good amount of water, proper breathing, good physical activity and proper rest. The body chemistry is also greatly influenced by mental state of the person as well as energy flow through meridians of the body.
Mind
The mind is place of memory, the seat of consciousness and way, state, or direction of thinking and feeling. The mind is also the bundle of running thoughts. All our activities either through way of thinking or doing activities using physical body will get stored in the memory. They are called habits and once habits are strengthened by the repetition, it becomes character. The brain is the physical organ which houses the mind. The healthy mind is the one which is calm, relaxed, focused and take instructions from us.
Spirit
The spirit is the very subtle internal energy or the real being living inside of us or the awareness of the self. Breath is only physical connection between body and spirit.
We will feel joyful and at ease within ourselves when there is balance between mind-body-spirit. Energy will flow freely and we will be at our best to deal with anything in our life. This could be achieved by certain systematic way of living. We are product of our habits and choices. The balanced way of living can be initiated by training which involves mind-body-spirit together. As we train and live, we will gain the freedom from our habits and the way of living becomes choice for us. We can choose to live happy and peaceful.