The “Cyclic Sigh” is a simple but effective method uses targeted sighs to promote relaxation, stress reduction and emotional balance. In a 2023 Stanford University study, this breathing technique was shown to be the most effective at reducing anxiety and improving mood with a 5-minute daily practice.
Execution: Deep inhale through the nose, then another additional inhale through the nose, then long full exhale through the mouth.
This exercise will have greater benefits if you practice it regularly, on the other hand even a single physiological sigh when you are nervous / anxious can have a positive effect.