The exercises (asana) as we know them today have only been around for a few hundred years and were originally developed by yoga practitioners to enable them to sit comfortably for long periods of time during meditation.
Just in India Yoga is a 5,000 year old philosophy with its roots in India, it teaches principles for physical and mental health as well as spiritual growth.
The journey of self-exploration is gaining popularity among the aging and physically challenged members of our society. This is not surprising. The later years of life are an ideal time to use yoga as part of a journey of self-discovery, growth and contemplation.