Breath is the existence of living. It depicts your exact state of mind. Hence, if you notice anger will fasten the pace of your breath while sleep and relaxation will ease and prolong the breath.
Infact, research has shown that meditation (that involves breathwork) can have a major effect in relaxing the nervous system.
So here is one such breathwork that you can practice everyday in order to be able to manage stress.
Box Breathing:
1. Breathe in from the stomach for x counts
2. Hold the inhaled air for same (x) counts
3. Breathe out (exhale) for x counts
4. Hold this state for x counts
5. Repeat the above steps for 5-10 cycles few times a day.
This small exercise will not only regulate your emotions but will also be effective in clearing your thoughts.