What is the difference between a dead body and one that is alive? Well basically that - "alive". A live body has an electrical charge and electricity comes in two forms, it is either positive or it is negative.
Positivity adds and negativity subtracts.
So a person who practices yoga puts their body into a positive state therefore adding to their life and their total well being. Positivity is something that is a "being." If you have to stop and say to yourself-"be positive, be positive"- then you are not. This is a reactive state, however it's still better than not trying at all.
Being positive adds to the quality of your life. Your emotional state is always up, you will experience joy and have an enthusiastic outlook on life. You will view things with optimism not pessimism, you make proactive decisions not reactive People will enjoy your company, you will add to their lives and enrich them with your presence.
By practicing the yoga postures(asanas) you promote a state of continuing rejuvenation and is energizing. These all add to the charge that your body lives and gives off. That is why Yoga is the perfect exercise