During mantra meditation, the amount of adrenaline in being released into your blood goes down. While meditating, your cortisol level drops and stays low for hours afterward. Cortisol is known as the stress hormone although there are several stress hormones, including adrenaline. But cortisol is one of the most important. It is present in your blood in small amounts all the time, but when you experience stress, your body produces quite a bit of it, and in high amounts, it has unhealthy and unpleasant effects. Getting it out of your blood stream, in contrast, has healthy and pleasant effects.