Respiratory training efficiency, Airofit, spirometry and pneumothorax
An attempt to evaluate the efficiency of respiratory training with Airofit in terms of observed lung parameters via spirometry.
Why should you engage in respiratory muscle training?
It’s not clear whether you should. There’s not much good research on that type of training, but if you’re competing on a level close to professional, it’s probably worth trying as it doesn't require much time and effort and probably can somewhat increase your results. At least according to the research-backed info on the Airofit website. People suffering from COPD and asthma may also see some benefit, although it’s arguable what would make more sense for them: say, jogging or breath training. My sport of choice is squash which is a mostly anaerobic activity. Squash requires good brain function at a high heart rate to keep predicting what the opponent is going to do and repeatedly selecting appropriate countermeasures. In challenging matches, I sometimes felt like my brain goes into power-saving mode and attention slips away, at the same time you feel out of breath. Thus I came to an idea that respiratory strength may be one of my limiting factors for progress in squash.
Spontaneus pneumothorax and pleurodesis
My personal motivation was further enhanced by several cases of spontaneous pneumothoraces (SP) which I suffered in the early twenties (I’m 29 now). SP is basically a collapse of a lung which happens for no reason and at any time. It poses no danger for an otherwise healthy individual and is easily fixed in a hospital within a few days; the lung restores its normal shape and volume. Sometimes, you may even recover without any intervention. If SPs keep occurring, the patient undergoes a procedure called pleurodesis: the pleura (coating) of the lung is “glued” to the walls of the pleural cavity via povidone-iodine or talc. It’s a rather safe and has little long-term side effects. However, the amount of research is tiny, and I was bothered with a question if my respiratory performance is downgraded due to pleurodesis. Evolution did not attach the pleura to the pleural cavity for some reason, so there may be sense behind that design. I underwent pleurodesis on the left lung, SPs on the right lung resolved by themself. Airofit does not recommend people who've recently had SPs to do respiratory training. My last case was over 5 years ago, so I felt safe to train at full intensity.
Training intensity and programs
After doing initial spirometry (with and without bronchodilation) I proceeded to respiratory training. I kept my usual training regimen as before, just adding 1–2 airofit sessions, 4–8 minutes each, per day. I adjusted the duration and intensity of the sessions so that they’re challenging but not overly tiring or painful. The following programs from the airofit application were completed: anaerobic threshold, respiratory strength, endurance and running 1.
An important moment is that I was doing a significant amount of aerobic (3h+ a week) and anaerobic(1h+ a week) training for a few years preceding the respiratory training with Airofit, so I thought that any significant result achieved with respiratory training could not so easily be archived with my conventional training routines.
COVID-19 experience
I’ve suffered from confirmed COVID-19 for around 7–10 days with very mild symptoms (37C temperature, tiredness, loss of smell) during this 3 month period. I stopped my respiratory training for a few days when the symptoms were most severe, but quickly resumed it, nevermind the low-intensity pain in the chest when breathing fully in. My SpO2 was 98–99 all the time, and the respiratory parameters tracked by airofit did not decrease, so the disease did not severely affect the lungs, if at all. Respiratory training may, in fact, contribute to successful recovery from COVID-19, although this aspect is underresearched and is more like a hypothesis. Johns Hopkins recommends doing breathing exercises as a part of a COVID-19 recovery routine.
Results based on the Airofit app
My initial vital lung capacity was 7.2 L which is 150% of the predicted capacity for my weight and height. So I didn’t do the Airofit vital capacity program and didn’t focus on improving that metric. The “endurance” program in the app does offer some exercises for vital capacity, and I surely did archive the greatest testing results (up to 8.7L) when taking this program.
The testing with Airofit seemed rather inaccurate, as some air escapes between the mouthpiece and lips. There also may be issues with the sensing accuracy when inhaling or exhaling at full speed. Spirometry appeared a much better way to estimate the results, it’s also quick and cheap, so you definitely should consider it when doing respiratory training.
Inspiratory pressure, measured in centimetres of water pressure, did show a huge upward trend, increasing almost 2-fold. This metric, when testing with Airofit device, seemed overly dependant on your experience of doing the test. Basically, when you realise how you should inspire to archive the maximum test result, the red line skyrockets. Taking that into account, I would estimate my real progress as growth from approximately 130 cm H2O (120% of the average value for the person with my parameters) to 185 cm H2O(165% of the average value), which is still a 40% increase. Once again, it’s way better to rely on a more accurate test, but, sadly, spirometry doesn’t include pressure testing.
Expiratory pressure was my weak spot: the first test shown a value of 89–95 cmH2O, which is only about 60–63% of average. The results after three months of training did show a significant 1.5-fold increase to about 90% of average. I did attribute the relative weakness of my expiration to my pneumothorax issues. As the left lung’s pleura is “glued” to the pleural cavity, it may restrict the ability of the lung to compress and push out the air. The training may stretch the connective tissue between the pleura and the pleural cavity and increase its elasticity (just my thoughts on that, no proofs). Thus, I presume, my progress was fast and steady. However, I’m almost sure that if you’ve had spontaneous pneumothoraxes in the last few years and didn’t undergo pleurodesis, the pressure put onto your lungs with Airofit training can rupture the remaining blebs in your lung. You should definitely consult with a pulmonologist and do a CT lung scan before starting the training. I was going to do a CT scan myself to see if there is any damage or change in the lungs after training, as I did have some pains, especially during COVID-19 illness. However, all the CTs are occupied in the coming months with people with severe COVID-19, so I postponed it and will add the results later.
Results based on the spirometry
Now that’s the most interesting part! The mechanics of the spirometry seemed able to obtain reproducible results: the device doesn't provide almost any resistance and you breath out everything you’ve got very fast. It’s also easy to do several tests in a row to increase accuracy, compared to Airofit testing, which takes more time and effort and is more tiring.
The tests were done with the same specialist, on the same device and at the same time of the day. I didn’t train the day before doing the test.
Unfortunately, the spirometry I’ve taken didn’t measure anything regarding the inspiration, so the only data left to compare was FVC (forced vital capacity) and PEF (peak expiratory flow).
FVC has increased from 6,85 L (other results on day 1 being 6,78 and 6,74 L) to 7,46 L on day ninety (other results 7,44 and 7,33 L), which is a 9% increase or over 600ml of extra volume.
PEF has increased from 12,89 L/s (other results 12,15 and 12,64 L/s) to 16,59 L/s on day ninety (other results 15,7 and 15,4 L), which is a 29% relative increase or +3,7 L/s of flow.
A grain of salt
It’s not clear whether increasing FVC and PEF would increase your sports performance. Naturally, athletes have higher FVC and PEF than sedentary adults, but it’s not clear what happens if you further increase these parameters. Checking my VO2max after 6 months of respiratory training would be the next step I’ll take. This small study did not find any benefit and this as well, but this one did see some benefit beyond the growth of respiratory parameters. So you should do the tests yourself and see if it works for your body.
Spirometry after 3 months of no training (April update)
As mentioned before, I was training with high intensity with Airofit from August to November. Then I did fewer sessions in December and January and almost completely stopped the training up to April. I decided to do another spirometry and check whether my respiratory strength has rebounded to the baseline.
FVC went down from 7,46 L to 6,79 L (baseline 6,85 L). These are all maximal results after 6 tries.
PEF decreased from 16,59 to 13,94 L/s (baseline 12,89 L/s)
No surprise here: in absence of training the results went almost completely back to pre-training numbers.
According to Aerofit application data, the maximal expiratory and inspiratory pressure remained exactly the same as 3 and 5 months before. As for the lung capacity: I was still able to get a result of around 8.4 L on an Aerofit lung test (my all-time high being 8.7L), which contradicts the spirometry results. This further underlines the point that lung test results in the Airofit app are not too reliable and have huge variability (especially lung volume).
Conclusion and speculations
According to the spirometry results, even a modest amount (under 10 minutes) of everyday respiratory muscle training can contribute to your respiratory strength, even if you’re already moderately trained.
Taking spirometry before the start and after 1.5–3 months of training makes sense as you can check if you’re wasting time on these breathing exercises. I’ve had lung issues in the past, so my results should not be true for everyone.
For my case, respiratory training seems a great complimentary routine with visible results with just a small time investment. Airofit recommends doing up to 20 minutes per day, so probably even greater results can be archived for certain individuals.
This type of training will not contribute to your cardiovascular health or muscle mass, so better engage in regular fitness first to get the maximum scientifically proven benefit.
Conflicts of interest
I’ve no relation whatsoever to Airofit or any other respiratory training device.