As we practise meditation, we learn to prevent being reactive to our thoughts, we train our brain to reduce the connections that are responsible for producing cortisol, which is our stress hormone.
Breathing is intimately connected to our heart rate, blood pressure and the secretion of adrenaline and cortisol. High Arousal turns on our stress response which is our fight or flight mode.
Whilst we cannot control our stress response directly, we can certainly implement some strategies into our lives to help - Checking in with ourselves is one of them!