Recently JBV posted and said there is research the the gasp reflex can be controlled and that claims of risk from gasping and hypothermia are over stated. As part of a community of people who do not wish to flame each other, but who wish to learn the most accurate information, and share it with all for each to incoporate as they see fit, could JBV pleas share this research so we can have a discussion of this in good faith and with open minds?
My understanding up till now is that it may be possible under some conditions, ie with less skin surface getting exposed, thus less gasp reflex strenght, if not reflexive panic, if less heart arythmia, if no cold water dizzyness, if head not immersed, with trained individuals to sometimes limit or stop gasping. But not a sure thing in all people at all times, and not something to count on. My understanding about how long one can use ones arms to get out of water is that upper limit is 10 minutes, that each effort leads to quicker exhaustion, and that is in non moving water, low or no wind and depends on how long one takes to get out of boat, etc.
Here is JBV’s post:
sub 40 degree water does not kill within
Posted by: jbv on Jan-23-05 12:30 AM (EST)
seconds or minutes. if you can suppress the gasp reflex (and you can) most fit people will remain conscious for at least an hour with diminishing muscular function as time passes.
remember the 1, 10, 1 rule. you’ve got a good minute to control your breathing and calm down, 10 good minutes of your limbs functioning well to carefully exit the water and if you can’t- an hour before it’s lights out.
i work with a prof who is the worlds foremost authority on hypothermia (he has induced hypothermia in himself more times than any other researcher) and he has proven this time and time again. in 10 years from now, these facts will be prevalent and hypothermia treatment regimes the world over will be different than they are now.
It Took Me About A Minute
to get my breathing under control when I capsized in cold water. I think it really helped knowing that I could have waded to shore (water just over my shoulders) and had experienced help nearby. I didn’t panic at all. I felt that I had full strength for an assisted rescue for the few minutes it took to get back in my boat. The rule sounds right by my limited experience.
Lou
Will a hood prevent gasp reflex?
I’m very interested to know more also. This is my second season of paddling through the winter. I believe in rolling at some point during every paddle, so I do roll in icy water. In icy water I always have some type of hood on. I’ll get brain freeze if I do more than 2 rolls and I may loose some balance if I get too much icy water around my ears (I need some good ear plugs), but I haven’t yet experienced the gasp reflex. Will I never experience it as long as I wear a hood?
BTW, I’ve read Brian Nystrom’s experience with the gasp reflex in 50 degree water. Definitely makes me concerned.
NelsonL
sure
the focus on the gasp reflex is a way to point out the very clear danger in what at first appears to be benign conditions in calm water. A young drunk is at the dock taking a leak and tips in,he’s gone. A sailor in a regatta falls overboard without a pfd,boom he’s gone. Locally I read in the paper about two guys in a canoe and a friend in a kayak,the canoe goes over,they’re dead. So sure it’s controllable but the data on time to hypothermia is worthless if you’re experiencing vertigo from 15seconds of immersion,you’re exposed hands become worthless in 30seconds of immersion, your arms become worthless in five minutes of immersion,all long before hypothermia and long after a possible gasp reflex.
Practice and Repitition
But even for the professor it took practice - so he has confidence that he can keep thinking rather than panic. But how many people do that? I’d guess that the majority of kayakers rarely check out how water feels below about 50 degrees. And if someone has a panic response to overcome about the claustrophobia aspect alone (like I did and still have to work thru a bit each new season)… seems that any new research is still only likely to apply to the limited percentage that take cold water seriously enough to get a roll and practice it under cold conditions.
Kinda like the CRP blood test for someone with otherwise almost nill heart problem risks - it’s interesting but practical application may still be difficult. But maybe I’m wrong. At the very least, there may some neat new cold water apparel coming out of this research. More stuff!
Celia
Not sure about the “majority,” but have
flipped and rolled successfully in sub-50 degree water. Of course it helps to have the body well covered, and on some occasions I have benefitted from having a skull cap under my helmet.
I think it helps to have fairly well-developed roll routines, both for rolling quickly and for hanging in there a bit longer if an immediate roll is not possible.
I believe that “gasp reflex” and hypothermia are tremendous dangers, but I don’t understand why people treat the gasp reflex as if it were a totally irresistable force. As I noted in a previous thread, I used to have to dive to the bottom of a swimming pool early every spring to remove plugs from lines. I’m sure the pool temperature was still down in the 40s. I survived every time (no wet suit), though I would shiver in bed for an hour or two afterward. I essentially had total skin exposure during these dives, and I was a really skinny teenager.
Gasp and Diving reflexs
The gasp reflex, or cold-shock response is generated by exposing skin to rapid and substantial drops in temperature, intiating a usually overwhelming drive to breath, prolonged inspiration and tachycardia. The diving reflex (IME, still present in adult humans despite what the text-books say) intiates the opposite response, lowered drive to breath and a bradycardia. The diving response is initiated from the trigeminal nerves across the cheeks.
When you're in a dry suit and have a hood on, little skin is exposed other than that on the face - making the initiation of the diving reflex more likely than the initiation of gasp.
I don't think there is much research done on which reflex (gasp or diving) is the strongest. While I worked at the Royal Navy's Research institute we did try and test this - lowering a speedo-clad lab member either face or body first, then body and face at the same time, into a pool of 5degree C water. We didn't get anything conclusive and never followed up on it to my knowledge.
Experience and background
Yeah - I have practiced a roll in water that was 50 or a smidge under, and if I could count on it every time (still not there) would have no trouble at least trying it into the 40’s. For me, at 40 degrees it’s time to think snowshoes.
That said… anyone who can do that has been in the minority of any paddling group I have encountered. The groups are probably typical - evening or weekend paddles on inland lakes and rivers, guided groups on ocean bays or a bunch of friends going out together and camping on a MITA island. I have seen smaller groups where everyone seemed to be a quite skilled paddler, but they are quite rare.
So - my numbers are hardly based on scientific observation or whatever. But it still seems that, like most advanced skills, dealing aggressively with hypothermia will be avoided by the same paddlers who tend to place themselves at risk by not learning skills or having appropriate clothing and gear. I am not sure how any new technique can get around the human part of the equation.
Celia
Dive reflex stronger?
My sense is that many people actually UNDERESTIMATE the dangers of hypothermia and the effects of cold water. I’m not suggesting we paddlers treat these risks lightly.
But I believe many people have too much fear of the “gasp” reflex. It may exist, and it may not be a myth or a superstition. I’ve never experienced it myself, but that doesn’t mean it’s not real.
But my guess is that the mammalian dive reflex is much stronger and much more commonly activated. The only evidence I can offer is anecdotal - stories of people being unconscious underwater for a long time and surviving, etc.
But which would be more evolutionarily useful for us mammals? Which would be more likely to keep us alive if we ended up in cold water? Seems like the dive reflex???
V.
I don’t carry a thermometer
But I’ve rolled or swum plenty of times with ice floating along beside me. Always in a drysuit, sometimes with a neo cap, sometimes without.
Never had a “gasp reflex”.
I think that the point of Brian Nystroms article was that this was the first time he had experienced this even though he had been exposed to similar or colder conditions in the past. Makes me wonder if it might happen to me some day.
But I don’t worry about it. I dress to swim and I paddle with folks I trust to back me up if I flounder, whatever the reason might be.
For What It Is Worth?
Ain't no expert whatsoever, just wanting to spur discussion of personal experience and match it with research stuff.
I saw a medical article supposedly peer reviewed that said mammalian dive reflex much stronger in children and infants and much less present if at all in us adults. Also stated many other concerns such as spasm of the larynx,fluid in lungs from aspiration of stuff, and so on.
I too have had NO gasp reflex when only partially covered and then on another different occasion just the opposite, had a huge gasp I could barely barely moderate, and lucky head not in water. That is why I posted this. Post on!
Oh yeah here is the URL (don't let the title scare you away, yes primarily about children but talks about adults as well, may be helpful to those of us with kids or who care about kids)
http://www.hypertension-consult.com/Secure/textbookarticles/Primary_Care_Book/20.htm
My 2 cents
And from some personal experience.
If you are expecting it, it won’t happen.
The reason I say this is on several trips that I took to Alaska, I went (on purpose) into 38 degree water and did not experience it.
I also think if a person has all their life from the time they were a kid until adulthood swam in frigid water such as the Main coast or the northern Pacific will not experience it.
On the other hand if someone was born and raised in the tropics and then for the first time in their lives dumped into frigid waters I think they would experience it big time.
My thoughts and my opinion only.
Cheers,
JackL
Concur N-P
The Diving reflex
is still strong in adult humans. Years ago we used it as a practical example of autonomic nervous system tone with Medical students. The first year we had students dip their faces in ice-water we were pulling them out because of the rapid drops in heart rate and prolonged breath-hold times.
Although not appropriate, the gasp reflex is very strong, and if I were to guess after the one inconclusive study we did to see which was strongest, I’d have to go with the gasp. Kayakers’ habit of insulating all their skin but for the face, is probably the reason more paddlers don’t experience the cold shock response. The more skin you exposure, the greater the risk you’ll have a cold shock response.
Not just water temps
Similar to above - I’ve been able to feel completely comfortable in colder water, where I planned to go over and had practiced regularly up to that point. I have also been at the bare edge of controlling my panic because the alternative was to drown, in a 79 degree pool. (That was at first…)
The gasp response may be more complicated than controlling hypothermia.
Celia
The research I’ve seen
seems to indicate that the gasp reflex usually occurs when someone has NO protection from the cold water…NO pfd, cotton shirt, cotton pants…instant saturation. Unfortunately, there is very little info. that we have regarding it.
Suffice to say: It can happen, it does happen, protect yourself. The more protection the better.
On the other hand, you don’t need to don a 3mm wetsuit when first testing out the bath water.
Watch the video of the prof he cites
and get your answer. I think this is a video from him.
http://www.exn.ca/video/?Video=exn20020325-icewater.asx
Seems to me the prof is talking about the response being involuntary. He does not seem in control of his breathing at all. He even says that if you are underwater for the first gasp, you're drowned.
We do not have rescue crew standing by; we must be capable of rescuing, warming, and evacuating ourselves. If you are solo and you get that out of it when you are at sea (so that you are getting large uncontrollable shivers), you are in serious trouble.
Caution is indicated
I am a bit confused by his presentations
I have watched and read a number of his papers and presentations and I am a bit confused.
At some points he does (within a larger context) want to point out that the gasp reflex has a time limit, is less dangerous if one’s head is kept out of the water,(don’t freak out stay still it will end) and that you have time up to 10 minutes depending, and here is what is best to do.
However, he also states that it is involuntary, and if head under water you can and very well may die (in the video). On another video, paper he does also state that full on gasp reflex was first studied with folks in bathing suits and the model of it came from there. Thus, what happens is less when major areas that are triggers covered, face, armpits, torso, groin covered it is not always so strong.
However, there are so many other things that can and do occur, like ear dizzyness, throat closing up so can’t breathe, heart arythmias, loss of use of limbs due to gasping and change in PH, etc. It it seems like a mistake to count on the idea that we can condition ourselves or if did not happen last time won’t happen again, or if expect it won’t happen, I expected it and was somewhat covered it did not happen once next time big time. What to think. Still don’t know for me at least.
When I experienced it
I was wearing a 3mm farmer john with poly pro shirt under it, polartec and paddling jacket over it, PDF, neosocks & winter booties, paddling gloves, and a polartec hat. It was involuntary for me.
Lou
Good Link And FWIW
I also noted his comment about the initial involuntary action and hedging on what would happen if someone's head went under if the gasping was occuring. As kayakers, when we go over, our head is almost always pulled underwater. If you got a roll or a strong high brace, you can come back out in matter of seconds. If you don't, you may well be under longer...
FWIW, I took a good thrashing in winter surf last winter with the water temps close to the freezing point. I had on a drysuit and fuzzy rubber hood and a 3 mm neo hood over that. The first couple of times I got maytagged under I was okay, warm in my drysuit and experiencing a serious ice cream headache. But I was able to keep myself calm and kept reassuring myself that I would come back up with the help of the PFD. I must had been maytagged 4-5 times to the bottom by dumping waves. I remember my breathing getting more difficult and it took more focus to keep calm and to keep swimming with the waves to shore. My swim got mercifully cut short when others came out to pull me in.
In retrospect, having been sucked out of the boat and swimming through surf in similar wave conditions but warmer water, I now know I was experiencing the beginning stages of hyperventilation due to the cold exposure of my face, neck and head, and certainly not the swim effort. That hyperventilation made it harder to get air, increased the difficulty of staying calm and focused. I know I really had to keep telling myself, almost mantra like, to stay calm, trust the PFD and to just keep kicking to get further in with each successive wave. It was not a fun experience. I now wear a thicker, tighter hood for surfing and apply silicone grease all over exposed skin areas when surfing in the cold.
I take immersion pretty seriously these days when going out for paddles in the colder temps. In fact, I have serious reservations going out with anybody whose roll/rescues skills are suspect and/or not dressed to be able to withstand the cold to complete a roll or rescue.
sing