An exercise routine of 30-40 minutes a day is taken as enough, but that too significantly depends on body types. Even expert training programs online fitness training programs that knowledgeable ones guide do not promote an extra dose of exercise. 

Anything good when taken too much starts to show wrong effects, and the same goes with exercises. Understanding everything that is right for the body is essential if you are really serious about planning to take proper care of it. That is how health and well-being works.