Mammalian Dive Reflex

[hulagirl]

For my open water swim friends.

Do you find yourself gasping for air as soon as your face enters the water? Does it feel like your heart is racing and no matter what you do you can't catch your breath? Does it feel like your chest is tight and your arms weigh 2 tons?

This is the Mammalian Dive Reflex and I am CURSED with it.

Does anyone have any tips/tricks/words of advice on how to control it? I tried dunking my head into the water on Tuesdays swim. Instantly I began to shiver uncontrollably. By 500m I am usually calming down, but Tuesday was hell. It got worse and worse and by 800m I was either going to pass-out or my head was going to explode. Horrible swim.

This happens to me in a heated pool as well as open water. The pool version of it is not as bad. Maybe lasts 100m max. And I usually get through it with a kick board warm up. Also happens when I snorkel.

I have found only 1 article that relates to MDR and open water swims. It's a common thing that is dealt with in SCUBA diving. I read that it's a 30-45 min "symptom" that the body goes into!

Anyone have these same issues?

ETA: Hawaii is blessed with warm water so no wet-suits are allowed here. I do wear a rash-guard when I swim to help stay warm. I would guess the water temp is not below 70 right now. Pool is about 78. Air temp is 78-85.

Denise

[KnottedYet]

I just don't put my face in the water...

...seriously.

I've always swum with my face out of the water. I'm a slow swimmer anyway, so it doesn't matter. Mine is more a panic. Had a bad experience diving once (rip-tide, clinging to a rock, running out of air) and really get perturbed if my face is under now.

MDR slows the heart rate, reduces bloodflow to the extremities, etc. What you describe sounds more like a panic. The active reflex is to help us survive under water, it doesn't make us fight to get out of the water. MDR is what makes itty-bitty babies so calm and happy underwater.

Here's an abstract: http://www.springerlink.com/content/l831603655v86219/

Here is a paper by some folks who posit that the MDR's slowing of the heart rate could somehow be used to help calm a racing heart rate. http://www.sciencedirect.com/science...c&searchtype=a

I can't get the full text of this one, but it talks about how emotional arousal can counteract the calming and heart-slowing effect of the mammalian dive reflex - that would be the panic you and I experience which prevents us from experiencing a proper MDR. http://onlinelibrary.wiley.com/doi/1....cp020325/full

[hulagirl]

Knot - check out this blog:
http://www.internalmonoblog.com/2011...ld-water-swim/

Specifically:


"In the swim leg of the race, you may experience diving reflex as the feeling of the inability to breathe, gasping for air, the closing of the throat, cramping and panic. Clearly something you want to avoid Fortunately, you can prepare yourself for the shock and teach your body to handle it in a manageable way."

I suppose I should have noted that I do not have this happen to me in warmer water temps. As the temp goes up, I have less of a response. Shallow or deep, flat or rockin, the severity depends on water temp and air temp.

There is some panic that kicks in AFTER MDR starts - that's for sure!

[KnottedYet]

He's wrong.

MDR holds the breath, slows the heart, calms the nervous system, and redirects blood from the extremities to the core and brain.

It does not cause panic nor cramping, nor gasping.

The negative effects you, I, and he experience are from panic. MDR causes bradycardia, not tachycardia. It is deliberately evoked during some surgeries to calm the patient's body.

If we could get over our panic at experiencing the reflex, we'd be fine. But he's blaming MDR for something that is NOT caused by the MDR. You don't train your body to get over the MDR, you train your body to not panic. MDR is your friend in the water, and you cannot "train" it away, it is a reflex.

ETA: yes, MDR is stronger in colder water. Cold water sucks heat out of the body quickly, so it behooves the body to step up the automatic response a bit. Training yourself to get used to the feeling of the MDR so you don't panic is probably best done in colder water, since that stronger reflex is the one that sets your body into a fight-or-flight. Or you could just do like me, and never put your face in the water...

[HillSlugger]

Cold water on the face tends to stimulate a gasp reflex that can make it hard to breathe and easy to panic. I've dealt with that, and it's something you can get used to. Splashing cold water on the face, dunking the head, etc can prepare the body and reduce the reaction.

Something else I've dealt with is "freak out on go" syndrome Starting out too fast, getting out of breathe, and then panicking.

[Catrin]

This is why I never learned how to swim, outside of the back stroke Part of me would like to, but I just can't put my face in the water without panicking...