The water we drink, gets in our body and is thrown out in 4 hours, else we will fall ill. The air we breathe, has to be thrown out in 1 minute, else we will die.
What about negative emotions like hatred, anger, jealousy, insecurity ... we hold in our body for days, months and years.
If these negative emotions are not thrown out regularly it props up into psycho-somatic diseases.
And meditation and prayers are safest way to dissolve these emotions.