Preventing Hyperventilation Swimming Fast Snorkel Laps

[huffnpuff]

A. I swim one mile (35 laps) at speed in my local YMCA pool. Total time: 36.40 minutes
a) Accelerate every fifth lap for around down to 45 seconds.
b) Use a modified US Divers dry snorkel I made into a wet snorkel by taking out the "floater", and trimming excess plastic. Did this in the hopes of avoiding the discomfort mentioned below.
c) I never submerge.
B. I am 53 y/o, five stents in my heart, low dosage blood pressure meds (losartan, metoprolol, 25m)
C. Swam in this same fashion within the past couple of years...minor dizziness.
RESULTS: Major dizziness, heart palpitations, near blacking out.
I think I have gone from C02 poisoning (restrictive snorkel before modification), to hyperventilation, for using a snorkel just not made for swimming for an extended time at speed.
What do you think?
How do finswimmers avoid this? Don't they swim in pretty much the same way?
Sorry if I posted this in the wrong place.

 

[cdavis]

At that effort level, its pretty hard to hyperventilate to the point that c02 is reduced enough to constrict the carotid arteries- dizzyness etc.'' I know I could not.
Something else going on. Inadequate blood supply to the heart?

 

[huffnpuff]

Well, I do have heart disease. Early onset, diagnosed at age 45.
And it IS a progressive disease.

 

[huffnpuff]

It is interesting to me that I don't have bouts of dizziness after a run.
The air doesn't have to go through a "middleman" (snorkel).
It also seems that were there to be an inadequate blood supply to my heart, I would experience chest pains.
No pain, however.
Hmm...I guess my cardiologist will elaborate, hook me up to a diagnostic machine, or both.

 

[vali]

How much you shorten your snorkel?
when you run , perhaps you inspire air true your nose [lower speed and lower volume/time in comparison with mouth breath]
I also have some heart disease called Atrium fibrillations. I can live with those fibrillations, but because the bad circulation of blood, I sometimes hyperventilate to easy, even when I do my breathing exercises correctly.

 

[Vov]

Hmmm, have you guys made any continuous efforts to recover your heart conditions? Have you tried drinking more water with some salt and some baking soda, Buteyko breathing, water fasting? It only seems strange at the beginning.