Hi Guys,
I have never joined a chat group before but having read your descriptions I wanted to be in touch and give you my thoughts.
I am a doctor, a medical specialist. I have the same symptoms as you. They began when I was a child. Intermittent. I remember waking at night and telling my Mum I couldn't click my breath over. She was matter of fact. I'd get warm milk by the fire, reassurance and back to bed. It came intermittently.
As a young adult I began to associate it with periods of changing exercise intensity - if I upped my exercise, eg I began jogging, or swam more than usual, within days it would begin. If I let my exercise slip it would also flare but not as bad as when I upped it.
Between 8 and 15 weeks into my first pregnancy it was terrible. I suspect this was a change in my progesterone levels affecting my blood vessels.
Being quite fit the past few years has helped - when the need to "click over" my breathing intensifies being fit feels like it makes my diaphragm stronger and better able to make the breath "complete'.
In recent weeks however my clicky breathing has flared and is the worst I have had in years. I suddenly realised that my husband and I have increased our exercise quite markedly during the lockdown, doing a long walk through the hills every day. I also run with quite a low standing BP.
The past few days it has been terrible, on a 2 to 10 minutely cycle; increasing urge to have to get my breath "clicked over". I alternately try to do it, then give up because the lack of a "successful" breath feels so awful, and try to just ignore the background feeling until it suddenly bursts forth so severely that my diaphragm activates and my breath clicks over and I immediately feel relieved and back to normal... for a few minutes till it all goes again. yesterday I was working on a project I enjoyed. i decided to time the 'cycles' of needing to 'gasp'. It was running at about 4 1/2 minutes for the urge to begin, to 6 minutes when i could click it over. I found rhythmicity interesting as I was not "watching the clock" between times.
I am absolutely sure you guys know what i'm talking about because I believe we have a condition which medical science has yet to grasp or take seriously. Unfortunately, now, this condition has been put in the mental health basket and labelled "panic" and/or "anxiety" disorder and thus no one will ever try and figure out the true cause. These labels are great when they are correct, and it can be useful to learn skills to cope with insoluble symptoms, but i believe many people have been given these diagnoses for these symptoms and either accepted the diagnosis because it came from a doctor, or they knew it didn't fit, but realised that trying to argue it is pointless and just proves that you have mental illness with a lack of insight.
No one who doesn't have this would understand how much it can exhaust you physically and do your head in with it's intrusive symptoms and no coherent explanation. i explained to my husband that it's like I've got a faulty fire alarm in my chest. It is set off if my breath isn't "right". When it goes off it's so loud that it is impossible to ignore. It is screaming at you that you have to take a deeper breath. The big question is, what is "faulty" and setting off that alarm? i believe anxiety is primarily secondary. Mine is not related to anxiety but I gave up talking to doctors about it because they are so determined to stick it to that. I have had all sorts of the usual anxieties and stresses in life and my breathing at and around those times has been fine. Then 'out of the blue' I have it for weeks. No one in this big complex world of ours has a life without stresses and anxieties and thus any medical professional who wants to will always be able to find something psychological to hang it to. For those for whom that explanation resonates I say go for it, but if not, please don't just cave in and think that they must be "right". You really will end up with an anxiety or a panic disorder.
My thoughts:
The feeling I get in some ways is very like when I was fully pregnant and lay on my back - this diffuse extreme "anxiety" that something was wrong, deep in my chest, and I had to move position. This is accepted in pregnancy. No one says oh that's because you're anxious about having a baby -they say oh that's because the baby is pressing on your vena-cava. I know my Oxygen is normal throughout my attacks. I know I am not over breathing.
I also believe the relief that I get when my breathing "clicks" is instantaneous and this is too quick a response to reflect a change in my alveolar CO2 or oxygenation. I believe that if it is primarily lung related then it is more related to some sort of pulmonary (lung) blood vessel stretch receptor or something. It may be that our blood flow into our lungs is not giving the correct 'stretch' signal - maybe we have low vascular pressure in our pulmonary vasculature - in a certain region where there are receptors doctors haven't even identified yet. By activating our diaphragms and taking the deepest breath we can what we are actually trying to do is increase the negative pressure in our chests to suck more blood into our lungs so the "enough" feeling is triggered. As soon as we trigger the stretch receptor it sends the relief message to our respiratory centre and we stop 'gasping".
I do at times wake at night, suddenly, from deep sleep, with a need to click over my breathing. Frustrating because all I want to do is go back to sleep. But interestingly, I think when this happens I am almost always lying on my back (my normal sleep position is on my side) so I roll to one side and seem to be ok again.

[It is also worth seeing what your BP does when you are lying and standing, and also your pulse rate to see you have an associated postural problem maintaining your blood pressure. I think for some people, increasing exercise does things to the autonomic nervous system that we don't yet understand. it's important to have a doctor check you out fully, too, to rule out recognisable lung or chest disease but please, if these are your symptoms, don't be surprised when everything comes back normal. See the good in that]

Other thoughts: As I am sure you are aware, one of the most reliable ways to trigger the "click over" is to yawn. I have to wriggle my jaw side to side to evoke a yawn. When that doesn't work it's awful (and my jaw starts to suffer from all the wriggling).
Finally, my other thought which I believe is worthy of exploration. I have a young adult son who has tourettes. He is off at university at present. I realised in recent years just how like a "tic" my clicky breathing is; the urge occurs. it builds up and up and I have to do the "response" to satisfy the urge and the urge melts away instantaneously - only to return again and again. I have therefore often tried to ignore the urge and let it build and build because with tics, if you do this and can maintain the "pain" of the urge long enough, the urge will often finally wane. This definitely works to an extent but it takes a lot of effort. Amazingly, my son told me recently that one of his many tics involves the need to take a deep breath to get rid of the urge that he is being suffocated. I asked him what he did about it. He said he gets embarrassed with people seeing him yawning and trying to take deep breathes all the time but apart from that nothing, because there's nothing to be done, it just is.
Tourettes is a neurological condition. Tics are not psychological even though you can exert some control over them in the short term.
Unfortunately many people misclassify tics as "just a nervous tic", failing to recognise the morbidity they can inflict.
My mum died a few years ago. She was a private person but I think she got this also. I think it's why she recognised it in me as a girl and was so matter of fact about it (she never thought to get me medically checked out because she was confident it was just something that we got).
Guys I have to go. Would love to keep in touch. I believe you. I know we have something. We have to create enough noise so that people start recognising it as a condition and properly researching it, not just sending us to counsellors to get us to deal with the consequences, rather than address the causes.
Remember the story about stomach ulcers; physicians always told patients that ulcers were secondary to stress and sent patients for counselling (and guess what, everyone had stress that they could blame). Until the 1980s, when an Australian physician, Dr Barry Marshall, finally looked deeper and discovered that no, in fact, stomach ulcers were caused by a difficult to identify bacterium they called helicobacter pylori. Suddenly, instead of counselling, people got antibiotic and proton pump combinations and everything changed (for the better, unless you were a counsellor). Barry Marshall won a nobel prize for this work.
If there is one thing you can do, collect together people who think as we do, and try and find an open minded, interested and brave physician who is prepared to revisit this and investigate it in different ways. We will find an answer one day.
In the meantime, stay strong, and know you are not alone, and you are not going mad.
And it will settle.