But it's not working. My heart is still going a million miles an hour.
I'd experienced episodes of rapid heartbeat ever since I was a child. My mother told me they were called palpitations.
I mentioned them to a doctor once when I was a teenager and he jokingly asked if they were triggered by watching gyrating rock stars in music videos.
I took that to mean they were nothing to worry about.
Besides, I somehow discovered over the years that if they didn't go away by themselves, I could stop them by holding my breath for a short period.
The advice to try the weird legs-in-the-air trick came from a different doctor, decades later, when my heart-racing stints were getting a little out of control.
They were happening often and holding my breath wasn't doing the trick, so I'd just wait for them to peter out.
But one day, after five hours of my heart racing relentlessly and feelings of breathlessness and light-headedness, I decided enough was enough and took myself to hospital.
By the time I got to there, the trotting in my chest had stopped.
Despite this, to my surprise, I received immediate attention. While my ECG (heart trace) was normal, they wanted to investigate more.
'You might have had a heart attack'
The first clue that I had been too complacent about my health was when my blood tests came back showing something that surprised even the doctors.
Chemicals called troponins, released when heart cells are stressed or damaged, were elevated.
I was told I "might have had a heart attack" and they'd be keeping me in overnight to do some more tests.
I was dumbfounded. And a little cranky.
I didn't smoke, tried to eat well, and made a fairly consistent effort to do some kind of regular exercise.
A heart attack? Seriously?
Confirming the diagnosis
More testing showed it wasn't a heart attack, and that I was likely dealing with a type of abnormal heart rhythm or arrhythmia known as supraventricular tachycardia (SVT), a condition that affects about one in 400 people.
But until the doctors could get an ECG done while my heart was actually playing up, they couldn't say for sure.
The opportunity came a few months later, when my racing heart struck again during my commute to work, which turned into a commute to hospital.
When hooked up to a monitor, I learned my heart was clocking an impressive 179 beats a minute.
And the pattern of squiggles on the screen was instantly recognisable to the doctors as the tell-tale fingerprint of SVT. To the untrained eye, it didn't look much different — just a lot more peaks.
Within a few moments, a crowd of medical staff had gathered around me as I was injected with a chemical called adenosine to bring my heart back to normal.
It would happen in a few seconds, which might feel a bit weird, I was warned; like you're going downstairs and you miss a step.
That was a pretty good description. All eyes were on the heart trace monitor as the adenosine did its stuff and sure enough, within a few seconds, my ECG "reverted", as they say in medical speak.
The crowd dispersed, the spectacle over.
The good news about SVT, which isn't the case for all abnormal heart rhythms, is that it is not usually especially dangerous, as long as it doesn't go on for too long. However, it can cause people to black out.
In my case, the earlier five-hour episode had placed enough stress on my heart to trigger the release of troponins, the same chemicals emitted by cells damaged in a heart attack, albeit at lower levels.
I had felt exhausted for days after that time, as if my heart had run a marathon without the rest of my body. I was told it probably wasn't a great idea to let that happen again.
What's the Valsalva manoeuvre?
So back to holding my breath and that legs-in-the-air trick.
It turns out that by holding my breath and bearing down (I discovered this made it work better), I had unwittingly been performing something known as the Valsalva manoeuvre — a physiological phenomenon first described more than 300 years ago.
The manoeuvre is something doctors suggest people with SVT try so they don't have to be injected with adenosine.
Clever old me just worked it out by myself.
It works because it creates increased pressure in the chest cavity, stimulating the vagus nerve that slows the heart.
In recent years it has been shown that by adding a little something to the traditional Valsalva manoeuvre — that something involving lying on your back, legs in the air, thumb in your mouth and blowing hard — it works even better at stopping SVT, but still has only about a 50 per cent success rate.
And it is not the most inconspicuous posture to adopt at the bus stop or the middle of the office when a case of SVT strikes.
Time for action
In the end I opted for a permanent solution, a procedure known as cardiac ablation.
An electrode was pushed up through a vein in my leg to zap a bit of my heart that was serving as an extra electrical pathway and causing my heart to race.
It felt a little uncomfortable for a few moments, but nothing too bad.
I was done and dusted in a little over an hour, with just a small nick in my groin to show for the effort.
My story had a happy ending, but I was incredibly lucky that adopting a silly posture was as bad as it got for me.
Any chest discomfort that lasts more than 10 minutes, or gets worse in less than that time, is reason enough to call an ambulance, the Heart Foundation says.
Abnormal heart rhythms or arrhythmias can also be symptoms of serious disorders which can cause sudden loss of consciousness or even death.