The very first obstacle that the Yogi will encounter is ill health or sickness. To the yogi his body is the prime instrument for the attainment of happiness.
If his vehicle breaks down, the traveller cannot go far. If the body is broken by ill health, the aspirant can achieve little. Physical health is important for mental development, as normally the mind functions through the nervous system. When the body is sick or the nervous system is affected, the mind becomes restless or dull and inert and concentration or meditation becomes impossible.