I'm not sure how having the weight of the abdominal organs
pressing up (OK down if you are on your head) on the
diaphragm is supposed to help breathing. You could just
tighten a corset around your waist until you turn blue for a
similar effect that will not risk cervical injury.

Well, there seems to be an astounding variety of ways of improving the
HRV.  Do  Google searches with
"hrv heart training"
"hrv heart training qi-training" for Chinese shadow boxing
"hrv heart training yoga"
"hrv heart training hearttuner" etc. etc.

Some of the methods would be too likely to provoke attacks of asthma
(hyperventilation in yoga exercises), to demand too much physical
condition or lead into extravagant New Age fantasies and years of
morbid soul searching. Qi-training (tai chi, qigong etc.) might be the
most acceptable.

However there is this clear message by Paul Lehrer, and its reception
in expert circles, to the effect that there is a different scientific
way of interpreting asthma. This would mean a new rationale, a paradigm
shift and the view that present asthma thinking should be replaced by a
better alternative.

Putting it differently Lehrer promises a way of  getting hard data on
yoga etc. so far known to have powerful but poorly reproducible
effects,  for asthmatics. Regards,  Richard Friedel

Well thank you Dr. Bob!

He writes:
"...In this day of increasing concerns about atheroschlerosis
(contributing to heart disease and stroke), osteoporosis, vertebral disc
degeneration and a litigious legal environment, I would recommend NOT
doing headstands.

If you look at the size of the vertebrae in the spinal column, you will
notice that they are small at the top, and get progressively larger
toward the bottom. The reason for this is because more body weight is
borne by each successive vertebra and disc. This is best seen in the
lateral, or side view:

http://www.netterimages.com/grossanatomy/images/image1.jpg

"Now, what bright individual came up with the idea of standing on one's
head, loading these small vertebrae and discs with the entire body
weight? I do not know, but it was not a gerontologist, a cardiologist,
or a chiropractor. It was no doubt someone who had no clue about the
risks associated with this particular posture...."

I had never before thought of the size of the vertibrae viz a viz upper
to lower and why the upper are smaller and the lower larger.  Makes
anatomical sense.

                     **********

As for Richard, is this a new Richard?  Really appreciate seeing a
handful of theories new to me.  However zany they might seem, there
might be something in any one or all of them.  Thanks Richard.---Jack