Difference between asana and exercises

ASANA - In yoga asana [poses] are the main part.It should be performed with breathing.It has a therapeutic effect.It cures all types of physical and mental diseases.It also improve concentration.Hath yoga describes 84 different types of asana.It describes such asana which are related to the physical and mental health other then the meditative asana.With the practice of these asana,the whole body gets activated and it becomes flexible,active and healthy.
According to Yog Darshan - स्थिरमसुखमासनम, जो भी अभ्यास सुख और स्थिरता के साथ किया जाए वह आसन कहलाता है .
EXERCISES - This is a fast activity in which heart rate,body temperature and breath rate increase.The effect are external and observable like increase in the muscle mass.These effect are the shorter period and can be measured.