There are no adverse effects as such. However, you need to be very careful while stretching and bending. Do not overdo anything that could lead to muscle injury. Too much of stretching in the first try can tear your muscles and damage your ligaments. Know your limits and keep practicing until you reach. By the end of the exercise cycle, you will be extremely flexible than you could have ever imagined being. Before you start with the yoga, do some cardiac exercises to burn more fat and get better stamina. Apart from this, there are no other side effects on the body.