From the perspective of freediver, Stig Avall Severinsen, PHD in Medicine, conscious breathing is one of the best defenses against respiratory illness as coronavirus, because if you practice conscious breathing, you strengthen your respiratory muscles among other things, which means that if you do suffer from pneumonia, whether that is caused by the coronavirus or something else, you are better prepared. 

Breatheology, The Art of Counscious Breathing is available to download at breatheology.com   

Victorious Breath (UJJAYI) Severinsen, Stig Avall. Breatheology – The Art of Conscious Breathing

 UJJAYI means ‘victorious breath‘ which refers to the breath conquering restlessness and stress. It is often called ‘the psychic breath‘, because it has such an enormous impact on your mental condition. The word may also mean warrior, and in this connection it refers to an expanding chest of a strong and proud warrior. In a figurative sense, Victorious Breath can be understood as conquering your inner demons: laziness, bad habits, fear, etc. Victorious Breath is a fundamental part of every pranayama exercise, and in Stig’s opinion is the most important of them all.

Execution:

The exercise is simple: inhale and exhale through the nose maintaining the mouth closed all the time; when you inhale, make a little constriction in your throat to produce an even hissing sound. When you exhale you can produce the sound “hhheee”. The key to Victorious Breath is the slight constriction in the throat, since this enables you to completely control the flow of air.

By varying the degree of constriction in the throat, you can determine the amount of air that enters (or exits) and its velocity. It is the key to your perfect breath, and no other exercise is higher, stronger or more effective than Victorious Breath. You can perform it anywhere, standing, walking, lying down, running or swimming. Apart of the altogether calming effect, Victorious Breath is also useful to people who suffer stress, depression and asthma.

Use UJJAYI pranayama in the following table (breathe through both nostrils with a small constriction in the throat) or use alternate nostril breathing (alternate between shutting the right and left nostril)

               Victorious Breath Table

	Inhal.	Breath Holding(full lungs)	Exhal.	Breath Holding (empty lungs)	Ratio
1. wk/m	4 sec	————-	8 sec	———–	1:0:2:0
2. wk/m	4 sec	4 seconds	8 sec	———–	1:1:2:0
3. wk/m	4 sec	4 seconds	8 sec	4 seconds	1:1:2:1
4. wk/m	4 sec	8 seconds	8 sec	4 seconds	1:2:2:1
5. wk/m	4 sec	8 seconds	8 sec	8 seconds	1:2:2:2

The seconds indicated in the diaphragm are consultative and can be of longer or shorter duration or be exchanged with e.g. number of heartbeats. Most important is the ratio inhalation: breath hold: inhalation: breath hold, that has to follow the table.

Each level is performed a minimum of 10 times in a row. Remember that you are not to become short of breath or gasp for breath – this is an indication that you have proceeded to quickly.

Since breath holding with full lungs and particularly with empty lungs is part of the exercise, it is important to progress cautiously and patiently. When to proceed to the next level can vary from person to person. You may be able to advance through the first levels within a matter of days. However it may require months to reach the last level.