Brain fog during and after deep(ish) /multiple dives

[Jack Hammer]

If I concentrate on air consumption I can usually "under breathe" the small male instructors with thousands of dives.

It's easy to build up CO2 when not breathing in a natural manner. Breathing shallow and skipping/delaying breaths doesn't allow for the CO2 to flush out of the lungs. Some folks further complicate this by breathing irregular in an attempt to control bouyancy. Deep and natural breathing, some folks reference yoga breathing, helps minimize CO2 buildup and reduces overall consumption.

 

[aviator8]

It is worth calling DAN and speaking to medical staff there. They can also help you locate a doctor close to you that is experienced in diving physiology.

 

[arew+4]

Based on BMI and gas consumption, i would guess you are in pretty good shape. What is your resting heart rate? Is it possible that the "diving response" is pushing it low enough that symptoms related to Bradycardia might become perceptible?

 

[MykaDives]

Seem like something it getting pinched or compressed. The pin point vision, did you also feel like you might pass out?

No. It came on suddenly, and left suddenly. Was very weird.

Myka, just wanted to be the first off the rails and get it out of the way.

I asked about cardiac work up because at 41 I had a heart stent for a 100% blockage. Symptom free until 3 months or so before stress test. No heart damage and stents now have good flow. Cleared for diving by Doc after stress/treadmill tests.

The only thing I can think of causing tunnel vision is reduced circulation or high Co2 but there may be many other explanations I've never heard of.

I'd still get another medical focused on diving. The tunnel vision would bug me nonstop.

I hope you get it figured out. Be safe.

Yikes! I am glad you are safe! I am female though, so my risk factor is much lower. I regularly exercise to 180 BPM, so I don't think I could handle that if I had a cardiac issue. The tunnel vision only happened once.

It's easy to build up CO2 when not breathing in a natural manner. Breathing shallow and skipping/delaying breaths doesn't allow for the CO2 to flush out of the lungs. Some folks further complicate this by breathing irregular in an attempt to control bouyancy. Deep and natural breathing, some folks reference yoga breathing, helps minimize CO2 buildup and reduces overall consumption.

I definitely use breath control for buoyancy fine tuning - maybe I am doing this too much. I do not breathe shallow, always very deep. I am diving this weekend and I will put some more effort/thought into breathing and see what happens.

It is worth calling DAN and speaking to medical staff there. They can also help you locate a doctor close to you that is experienced in diving physiology.

That is a good idea. I will do this. Thank you.

Based on BMI and gas consumption, i would guess you are in pretty good shape. What is your resting heart rate? Is it possible that the "diving response" is pushing it low enough that symptoms related to Bradycardia might become perceptible?

I don't know anything about "diving response" pushing BPM lower, is that a thing? Resting BPM usually 64-65 BPM. My cardio condition is probably better than the average Joe, but the average Joe is pretty bad. Haha! I've always felt like I was better at strength than endurance. I competed in Powerlifting a few years back actually, but there's no way I could do a marathon (kill me now).

 

[arew+4]

The Mammalian Diving Response: An Enigmatic Reflex to Preserve Life?

 

[Duke Dive Medicine]

Based on BMI and gas consumption, i would guess you are in pretty good shape. What is your resting heart rate? Is it possible that the "diving response" is pushing it low enough that symptoms related to Bradycardia might become perceptible?

That's a really interesting thought. Most humans lose the reflex as adults but there is a small subset of the population that retains it. The bradycardia is accompanied by increased stroke volume and blood pressure which keeps the heart muscle and tissues perfused, but if there's subclinical coronary artery disease it may be a factor.

Sometimes hyperventilation causes hypercapnea because of increased dead space ventilation as a percentage of tidal volume. It's a confusing symptom complex and I don't understand why narcosis (80 feet?) or hypercapnia symptoms would persist for hours after the dive.

If it really presents immediately on reaching depth on the first dive of a trip, then I agree that decompression stress is probably not what is causing THAT, but it might be what is causing his symptoms to worsen with repetitive dives or days of diving. Or, whatever is going on on the first dive is a different process than what is causing symptoms after the dive.

In any case, as always, I defer to you in the field of hyperbaric medicine!

Mike, from personal experience, hypercapnia symptoms can persist for hours. I've only had one CO2 hit, which came after playing slow-motion football with a sponge on Farnsworth Banks at about 150 feet in Mk-21, and it was a bloody awful one. Worse than any migraine I've ever had, and it too me out of action all afternoon. For hyperventilation to be producing hypercapnia it would have to be pretty profound and I'd imagine noticeable by the OP.

Well, I didn't want to mention it, because I figured you guys would be off the rails pronto, but I do have chronic vertigo (all day, everyday, for about 10 years). The reason I don't think the vertigo is related is because it is not an inner ear issue, but a visual sensitivity.

I was also diagnosed with asthma when I was about 12. I'm not sure that was ever an accurate diagnosis because there was no test performed - was simply, "You cough when you run in cold air, and your mom has asthma? You have asthma too, here's your inhaler." Speaking with my mom, she's actually not sure if her own asthma diagnosis is corret either. There has never been a time when I thought I HAD to use the Salbutamol inhaler, and currently they are all expired by several years. They help relieve chest congestion more than anything. On my list of things to do is to actually get asthma testing. What I find "most irritating asthma-like symptoms" is exercise in cold weather (like running below freezing temps), and MAYBE breathing cold air from a cylinder is causing some irritation and mild asthma is causing hypercapnea? I was kind of waiting to see what people would come up with before I presented this information.

Thanks for your reply DDM, air consumption is pretty good. I am female, 5'7", 130lbs. If I concentrate on air consumption I can usually "under breathe" the small male instructors with thousands of dives. If I'm not specifically thinking about air consumption, then I will use a bit more.

This raises the index of suspicion for CO2 retention for me.

Best regards,
DDM

 

[doctormike]

Mike, from personal experience, hypercapnia symptoms can persist for hours. I've only had one CO2 hit, which came after playing slow-motion football with a sponge on Farnsworth Banks at about 150 feet in Mk-21, and it was a bloody awful one. Worse than any migraine I've ever had, and it too me out of action all afternoon. For hyperventilation to be producing hypercapnia it would have to be pretty profound and I'd imagine noticeable by the OP.

This raises the index of suspicion for CO2 retention for me.

Best regards,
DDM

Good point! Maybe pulmonary function testing? She could be chronically retaining CO2 and have a reset capnostat with a reduced respiratory drive...

 

[Duke Dive Medicine]

Good point! Maybe pulmonary function testing? She could be chronically retaining CO2 and have a reset capnostat with a reduced respiratory drive...

Provocative PFT would be very reasonable. It would be interesting to test hypercapnic ventilatory response as well.

@MykaDives , just to cover all the bases, when was the last time you had your regulator worked on? Have you noticed anything about the work of breathing?

Best regards,
DDM

 

[Esprise Me]

playing slow-motion football with a sponge on Farnsworth Banks at about 150 feet in Mk-21

I'm wracking my brain trying to picture this but I can't figure it out...

 

[Duke Dive Medicine]

I'm wracking my brain trying to picture this but I can't figure it out...

Picture two narced Navy divers running across the bottom, one carrying a sponge like a football, the other trying to tackle. Passing of course did not work, but we had to try.