The ancient book of Gita, which is the treatise on the living has led a great stress on the karma. Karma is defined as the action and its fruits. Ancient Hindu saints have believed that a mans life is the direct result of his karma. Good thoughts, words and deeds lead to good and happy life while bad thoughts, words and deeds lead a person to disaster. This has been postulated in the 18th century by Isaac Newton, who gave his law as For every action there is an equal and opposite reaction.
The branch of yoga that deals with karma is called as the karma yoga. Usually you are bound by the cravings and desires associated with your act but you can free yourself by doing the act but dissociating yourself from its consequences. This is the basic concept behind karma yoga and the person who follows this path is known as karma yogi. His behaviour is of indifference and while the world may think he is not interested, in reality he has mastered his desires and has developed awareness of the real significance of the events that occur around him.
This yoga involves doing your duty without any reservations but is free of the cravings of the results that are obtained from the act. This attitude is difficult to acquire because we are taught to hanker after the fruits of our labour and any failure to obtain the desired results leads you to frustration and negative thinking. Also, constant attachment to the results leads you to stress, competition and aggressiveness. This has led to increased incidences of stress, diabetes, depression, heart ailments and suicides and has led many youngsters to use drugs, alcohol and cigarettes. Hence following the teaching of Krishna in Gita, wherein he advises Arjun: You are entitled to an action but not its fruits will lead you to a happy and stress free life.
A karma yogi realizes this and hence he follows the path of detachment. But this does not make him dull or inefficient. On the contrary, he channelizes his entire energy into the tasks at hand with complete vigour as his energy is not dissipated and gives it a best shot. Hence the results of his actions are the best and he gets good fruits. He does not run after pleasure but pleasure follows him. This makes him a pleasant person to be around and thus enjoys success in his life.