lightheaded

[knotical]

If it is related to the pool sessions, it seems strange that about an hour passed after leaving the pool before the episodes occurred. During that time I did the usual equipment disassembly, cleanup, shower, chatting, paperwork, etc.

I had also done a couple of pool sessions between the two I mentioned, without incident. It might just be a huge coincidence.

Thank you both, again.

[Duke Dive Medicine]

I was thinking along the lines that the OP was relatively horizontal while in the water and then proceeded to stand up upon exiting the water. I'd say that's consistent with orthostatic hypotension. It still doesn't explain why the OP is experiencing this now and not before. Presumably, he was diving fairly regularly over the past few years.

A cardiologist might be able to get to the bottom of this.

Agree with Knotical's post above - if it was orthostatic hypotension I think it would happen immediately upon exiting the water rather than an hour or so later. Knotical, we'd be interested in hearing what your PCP has to say if you don't mind sharing.

[Bubbletrubble]

Agree with Knotical's post above - if it was orthostatic hypotension I think it would happen immediately upon exiting the water rather than an hour or so later. Knotical, we'd be interested in hearing what your PCP has to say if you don't mind sharing.

Yes, orthostatic hypotension would usually occur within 3 minutes of changing from a horizontal to vertical position. There is, however, a phenomenon described in the literature as "delayed orthostatic hypotension" which would occur outside of that 3 minute window. Not much is known about the underlying mechanism, though. Some neurologists have speculated that it is an early sign of sympathetic adrenergic failure.

In my mind, there are several factors which could be causing the lightheadedness:

• The OP's blood pressure naturally runs on the low side of normal.
• He might be on an alpha blocker for BPH.
• There's a physiological mechanism which redistributes his blood supply underwater (more blood to core) that is being reversed upon exiting the water.
• There's a physiological mechanism (baroreceptor reflex) that normally prevents orthostatic hypotension when changing position from horizontal to vertical but it's somehow being inhibited (perhaps by alpha blockers?).
• He could be a little dehydrated.

I'll admit that the delay of symptom onset is a little perplexing. Perhaps it's related to the interplay of the above factors and the increased physical exertion of moving heavy gear from the pool to the car.

If the OP and his PCP want to pursue a medical diagnosis aggressively, the OP could expect a fairly comprehensive CV workup and possible tests to rule out neurological (autonomic dysfunction?) and endocrine issues. His doctor might also try to switch away from alpha blockers (if he's currently on them) for BPH treatment.

Let us know how everything works out...

[knotical]

Knotical, we'd be interested in hearing what your PCP has to say if you don't mind sharing.

Let us know how everything works out...

I shall.

Thank you both very much.

[Duke Dive Medicine]

Yes, orthostatic hypotension would usually occur within 3 minutes of changing from a horizontal to vertical position. There is, however, a phenomenon described in the literature as "delayed orthostatic hypotension" which would occur outside of that 3 minute window. Not much is known about the underlying mechanism, though. Some neurologists have speculated that it is an early sign of sympathetic adrenergic failure.

In my mind, there are several factors which could be causing the lightheadedness:

• The OP's blood pressure naturally runs on the low side of normal.
• He might be on an alpha blocker for BPH.
• There's a physiological mechanism which redistributes his blood supply underwater (more blood to core) that is being reversed upon exiting the water.
• There's a physiological mechanism (baroreceptor reflex) that normally prevents orthostatic hypotension when changing position from horizontal to vertical but it's somehow being inhibited (perhaps by alpha blockers?).
• He could be a little dehydrated.

I'll admit that the delay of symptom onset is a little perplexing. Perhaps it's related to the interplay of the above factors and the increased physical exertion of moving heavy gear from the pool to the car.

If the OP and his PCP want to pursue a medical diagnosis aggressively, the OP could expect a fairly comprehensive CV workup and possible tests to rule out neurological (autonomic dysfunction?) and endocrine issues. His doctor might also try to switch away from alpha blockers (if he's currently on them) for BPH treatment.

Let us know how everything works out...

DOH! I thought about that, wondered if it was outside the window, but maybe acting with fluid shifts after coming out of the water it could happen that late? Good post.

[knotical]

Update: -

As previously mentioned, my primary care physician suspected an arrhythmia and recommended we try to capture it on an EKG

Three months ago, and again about 30 hours ago, I had similar lightheadedness but both times immediately preceded by a strong feeling of reflux (the first one probably being my own fault) and both times the lightheadedness lasted for hours. The first time I was travelling and so did not capture it. For this most recent one, I camped on my doctor's doorstep until they opened. He annotated the EKG as:
"sinus rhythm
frequent premature ventricular contractions
supraventricular extrasystoles
anterolateral T wave changes
abnormal changes possibly due to myocardial ischemia"
And sent me to the emergency room.

The admissions nurse took one look at the EKG and had me hooked up to an IV, an O2/pulse monitor and an EKG before getting any more information than my name.
Blood work showed no enzymes that would indicate heart muscle damage, but a slightly low potassium level. Chest Xray was unremarkable.

Eventually a cardiologist who entered the fray called it "ectopic atrial beats" and told me not to worry.

I speculate that during the two pool sessions I might have triggered mild reflux by going inverted.