Just to break things down about #breathing exercise and airway clearance because I’ve been asked this question about celebrity endorsed exercises now an innumerable amount of times.

In short, breathing and deep breaths are good for keep your airways clean and open.

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Your lungs are equipped with an amazing system to keep your airways clean; the mucociliary escalator which uses mucous to trap junk that we breathe in to prevent that junk from getting to your lower airways.

Cilia in the upper airways mobilize the mucus containing the debris up to our carina (bottom of trachea) which stimulates the cough reflex to expectorate it out of the lungs.

At times this system can be over taxed or overactive like during an infection. Which causes the buildup of mucus and secretions. As a reminder with COVID and most viral infections, excessive secretions might not be involved. (See ARDS thread). They could be depending on case.

Our lower airways (including the alveoli) are generally dependent on our white blood cells to keep them clean (neutrophils and macrophages mainly).

One the best ways to clear out your lungs is to fluctuate the volumes and pressure of air that we move into our lungs. The air pressure and volume fluctuations help mobilize secretions through your upper airways to the carina to stimulate the cough reflex.

One of the best ways to do this is to exercise. When you are active/exercising your volumes slightly fluctuate breath to breath, you take deeper breaths, and recruit more parts of the lung. The airways also dilate because of the sympathetic response that occurs with exercise.

This is one of the reasons why you might notice a bunch of mucus and secretions come up when you take a walk or run especially if you have a chest cold or congestion.

The other reason why exercise and activity works for airway clearance is that staying in one position all day can cause temporary compression of lower airways. This can lead to the build up of secretions, if you don’t change positions.

For example if you lay on your back all day the posterior lung segments don’t expand well/much due to the compression of your bodyweight (and other changes). So it’s really important that you get up move around often throughout the day.

If you’re unable to move there are standardized breathing exercises that you can for airway clearance. These have been around for years & simple. They all are based on the principle of fluctuating breathe air volume/pressure helps mobilize secretions & opens up more areas of lung

Here is a great video from the NHS with my favorite airway clearance technique called active cycle of breathing (ACBT). What it involves taking 3 normal breaths, followed by 3 deep breaths. Repeat that cycle 3 times and then cough.

If you’re struggling to mobilize secretions using ACBT there are devices that you can utilize. These are called oscillating expiratory pressure devices. They operate by increasing back pressure into the lungs to open the airways via resistance in the device you expire through.

These devices also contain an oscillator which vibrates as your expire into it. This creates vibrations in the air pressure coming back into your lungs which helps break up secretions making them easier to be mobilized.

Again you can’t escape it. Changing volume and changing pressures helps mobilize secretions. That’s the general principle for how airway clearance works.

Another key principle is to adequate hydration. Dehydration makes the mucus thicker and harder to mobilize. So make sure you follow your fluid intake guidelines.

Now to the specific breathing exercises circulating around by celebrities. What they are doing is a technique called postural drainage (PDT). The theory behind this technique is using gravity to help mobilize secretions in the lungs by laying in different positions.

PDT has also been around for many years. However most of it is based on anecdote and tradition. The evidence for PDT is not great save for a few exceptions (young patients with cystic fibrosis, and bed-bound etc).

The evidence does not support PDT as a preventative measure either except maybe for those exceptions. And again there are many other options including just getting up and moving or some of those active techniques described above.

This exercise also stated that you have to breathe for a specific number cycles and depth. There’s really no evidence to support a specific number. Giving a specific number just helps cue people to fluctuate their breaths. We want people to remember how to do this independently.

And again as long as you’re fluctuating breath volumes and pressures it will mobilize secretions. So whatever number works for you is fine, a long as you follow these basic principles. You don’t need something over-choreographed. But if helps you remember, go for it.

And again the best airway clearance technique for most people is exercise and activity. Make sure that you’re hydrated.

If exercise and activity is something you can’t do try those active techniques or anything that’s going to fluctuate your breaths.

If you can’t do those active techniques try postural drainage.