Breathing exercise four-seven-eight breathing was a technique introduced by Dr. Andrew Weil, an American doctor who advocates alternative medicine.
Relaxing breath was thought to activate the parasympathetic nervous system to create a relaxing response.
This breathing pattern aims to reduce anxiety or help people get to sleep. The 4-7-8 breathing technique requires a person to focus on taking a long, deep breath in and out. Rhythmic breathing is a core part of many meditation and yoga practices as it promotes relaxation.
Unlax app provides both an instruction guide and a timing guide to practice "relaxing breath" technique.

Breathing exercise is thought to;

Affect on decreasing fatigue.
Effectively reduce anxiety
Reduce symptoms of asthma.
Help manage mental stress.
Help to reduce hypertension.
Reduced aggressive behavior in adolescent males.
Improve sleep and reduce time taken to fall asleep.