Tag Archives: Cold Habituation

Ice Mile Dilemmas – VIII – The Dangers

I’ve said previously that open water swimming is dangerous. Ice Mile swimming is even more dangerous.

I don’t think the IISA website, which is how most people are going to interact with and learn about the IISA or Ice Mile swimming, is anywhere near as comprehensive as it needs to be on its message about the extreme nature of Ice Mile swimming and there are few locations where this message is noticeable. Mostly Ice Mile and extreme cold water swimming is merely described as some variety of difficult, rather than life threatening.

The IISA needs to categorically state that Ice Mile swimming is inherently dangerous and should also do its best to provide a suitable and comprehensive safety framework for Ice Mile aspirants, which as I write this does not currently exist as I have proven in the IISA rules discussion.

Danger, Danger

All this talk of danger but it hasn’t been quantified.

This is a significant list. Some items are extreme versions of similar risks associated with open water swimming, but exaggerated because of the extreme cold. This list has been reviewed by two experts in cold water and hypothermia (one M.D. and one Ph.D.).

  1. Drowning due to involuntary water aspiration. In the first couple of minutes of very cold water, Cold (immersion) Shock can promote hyperventilation and gasping and actually lead people to aspirate water in the lungs, and drown quickly. This is the absolute and essential reason why it is best to get into cold water slowly, to allow your body to control the gasp reflex. Images of swimmers diving into near-zero degree water absolutely send out the wrong message to aspirants. I’ve been writing now for years that people shouldn’t do it. This gasp-aspiration danger exists in all cold water (which in research terms is water under 15 Celsius), but at such cold temperatures as under five degrees the risk is greater. It’s just one of the reasons why experience is so important and why the IISA should immediately introduce prior experience requirements for Ice Mile aspirants.

  2. Initial cardiac arrest. The body’s cold protective system, peripheral vaso-constriction, because it reduces overall blood flow, consequently quickly increases blood pressure. A sudden jump in blood pressure could lead to cardiac arrest in a small number of cases. In younger people this may be caused by sudden-onset ventricular fibrillation. Older people would be more likely to have a myocardial infraction (heart attack) as a result of decreased blood flow to the coronary arteries.

  3. Acute hypothermia. This should be obvious. Acute refers to the time taken for the drop to occur. If lethal temperature is reached in an hour, which is a good rule of thumb for almost freezing waters even for most trained individuals, then being immersed for more than half the time leads to acute hypothermia. Hypothermia takes some time to kill you, it can’t kill you from heat loss in 15 minutes even in these temperatures but kill you it eventually will if you don’t rewarm. Simply standing from the prone swimming position will cause the very cold peripheral blood, which can drop to a mere ten degrees as it lays under your skin, to flow into your core. Another reason the acute aspect is important is because in chronic hypothermia, which develops over a longer time, the body becomes dehydrated, reducing the volume and constitution of blood. In acute hypothermia, since one isn’t dehydrated, the blood pressure increase and therefore associated risk is greater. The onset of acute hypothermia is time based and why time limits are extremely useful in Ice Mile swimming but they are not currently in the IISA rules.

  4. Loss of fine and later coarse motor control/muscle failure. Peripheral vaso-constriction is something I’ve been writing about on LoneSwimmer.com since the site’s inception. It’s how your body protects core temperature by shutting off circulation to the extremities. That means fine motor control is quickly affected. Moderately hypothermic people have real difficulties with or are unable to get dressed. With the extreme cold of Ice Mile swimming, muscle control for such simple tasks as walking can become difficult or impossible. Muscle failure is the term Tipton and Golden, best known for hypothermia studies, use to describe the loss of muscle motive force. One cannot speak, or know what to do. I don’t know numbers (neither does the IISA,) but my experience has shown that most Ice Mile swimmers are unable to dress themselves afterwards. My partner Dee has taken to occasionally calling me The Joker, because of what she describes as the manic rictus manifested on my face as muscle control was lost after my Ice Mile.

  5. Acute Pain. The pain experienced once a swimmer is well into an Ice Mile, particularly in the hands and feet, is significant and sustained, possibly seven on a pain scale. It’s a precursor to number six.

  6. Temporary or permanent nerve damage. Within the community of extreme cold water swimmers there are cases of nerve damage or loss of sensation, particularly in the fingers. This problem can manifest as lasting from a couple of weeks to two years in different people. One medical doctor with whom I’ve spoken, who has direct knowledge in the area of hypothermia primary treatment, says that this is the range from frostnip to frostbite.

  7. Cognition impairment and memory loss. As blood cools, it becomes more viscous. Combined with the aforementioned peripheral vaso-constriction, necessary oxygen flow to the brain is reduced. The person loses speed of thought, ability to verbally respond and their memory is impaired. I can remember the end of my Ice Mile, but as soon as I stood up, everything became hazy and a series of disjointed episodes. One Ice Miler who did their Ice Mile in a group of four, said three out of the four did not remember finishing. This isn’t Hollywood; severely hypothermic people don’t retain the ability to think clearly. It’s why assistants and safety personnel aren’t just important, they are essential. The most common test we use for moderate hypothermia in swimmers is simply someone’s ability to give their own name. Most people with no experience of hypothermia can’t imagine this being a difficulty.

  8. Muscle pains, swelling or bruising, chronic fatigue and lack of concentration. These are symptoms which are displayed after extreme cold water swimming and rewarming. They only show after rewarming is mostly complete or even from the following day and may persist for several days. While some are minor, they are indicative of the extreme effort. The chronic fatigue and lapse in mental acuity are not related to the swim distance but the cold and could have significant immediate impact for swimmers who is driving themselfaway from an Ice Mile swim.

  9. Swimming Induced Pulmonary Edema, aka SIPE. Pulmonary edema occurs when fluid (usually blood) collects in the lungs and breathing is impaired to various degrees of severity. SIPE can be related to heart problems or infection, in the case of extreme cold water, while the mechanism isn’t fully understood, it’s likely that the increased blood pressure mentioned above is implicated.

  10. Cardiac arrhythmias. There are two types. Atrial fibrillation is irregular electrical activity which mainly affects the smaller upper chambers of the heart (atria) causing less blood to be pumped. It may even go unnoticed, or if noticed can result in heart palpitations and shortness of breath. One Irish swimmer who is already an Ice Mile swimmer wisely pulled out early in their second Ice Mile swim because of a sensation of heart palpitations. Ventricular fibrillation is also an irregular electrical activity, which affects the larger lower chambers (ventricles) of the heart. An incorrectly rewarmed person (such as through sudden application of heat or excess movement) will receive the full brunt of the almost ice-cold external blood into their core and around their heart too quickly. This can cause the heart to go into ventricular fibrillation. It is the leading cause of sudden cardiac death (SCD) and is the primary cause of death due to hypothermia. Stories of death through hypothermic ventricular fibrillation abound.

  11. Post-rescue Collapse/Afterdrop. With post-rescue collapse, the person can initially seem to be fine while exiting or after being removed from the water, but may later collapse or even expire. Tipton and Golden1 identify a number of post-rescue collapse deaths. In a study of 269 shipwreck victims, 160 were rescued. 17% rescued from water under 10 C. died within 24 hours of rescue whereas when the water was over 10 C. none died. One of many reported cases is the sinking of the SS Empire Howard. Twelve conscious survivors were rescued. The Captain reported that nine later died when taken into the warmth of the rescue trawler. In Ireland, three of the 15 fatalities during the infamous Fastnet Race disaster in 1979, occurred during rescue in water of 15 to 16 Celsius. The physiology has not fully been explained to date. Two of the all time great marathon swimmers, Ted Erikson and David Yudovin both suffered post-swim cardiac arrest from chronic hypothermia in water that wasn’t as cold, but in which immersion time was longer.

Ice Mile swimming is dangerous and so is post Ice Mile swimming as shown by numbers eight, nine and ten.

Items number nine and ten also portend something else.

Since SIPE, atrial and ventricular fibrillation can also be symptoms of heart disease or other coronary problems, the only acceptable standard that the IISA can set is to require a declaration of medical history and to preclude anyone with any history of coronary problems.

In Part VI, I mentioned that the IISA, which has a stated objective of promoting medical research, doesn’t even include any medical guidelines or medical barriers for an Ice Mile attempt it doesn’t even a require a medical application despite an apparent existing rule. In the light of these specific dangers, this is indefensible and must be addressed immediately.

Related articles:

Ice Mile Dilemmas I – The Trap

Ice Mile Dilemmas II – Surprisingly Cold

Ice Mile Dilemmas III – Black Rain

Ice Mile Dilemmas IV – Local Context

Ice Mile Dilemmas V – Rule 1 – Something Terrible Is Going To Happen

Ice Mile Dilemmas VI – Rules 2 – Safety and Experience

Ice Mile Dilemmas VII – Rules 3 – Failure To Apply Best Practice

References:

1 Review of rescue and immediate post immersion problems, prepared for the UK Health and Safety Executive, by the University of Surrey (Tipton & Golden, 1997)

 

Cold Shock Response and the Mammalian Diving Reflex in cold water swimming – Positive & Negative Feedback systems

I read a blog recently about cold immersion and cold baths, and cold swimming to a lesser extent. The author was speaking about the positive physical and mental benefits of regular ice baths. Similar benefits to what we as cold water swimmers regularly experience. All well and good. For aspirant Channel swimmers without access to regular cold water swimming, the recommendation for cold showers and baths is old and trusted.

However in his explanation of what was happening in the body the author focused exclusively on the Mammalian Diving Reflex as the primary response of the body when being immersed in cold water and completely ignored or didn’t understand the effect of Cold Shock Response and its place in the equation. (I didn’t save the blog link, sorry.)

That blog wasn’t the only place you see this. If you search on Mammalian Diving Reflex you will see it widely referred as the (only) process  in action when people are immersed or submerged in (cold) water. It’s a classic example of people taking all their knowledge from Wikipedia, because it seems the same Wikipedia core text is used all over the place.

I’ve covered both before and as a cold water swimmer, rather than someone sitting into a cool water bath, and I’ve focused as  much on Cold Shock Response, and the issue of Habituation, the process of getting used to getting into cold water, (not the process of staying in it).

The blog author just cut and pasted a Wikipedia article on Mammalian Diving Reflex, and while the Wikipedia article wasn’t wrong, both it and the blog were incomplete from the perspective of a  cold water swimmer.

So what are each of these and do they interact?

While swimming in Tramore Bay the other day, the water having risen by a degree in two weeks to about 7.5 Celsius, I got thinking about these two responses and how one, Cold Shock Response could be considered a positive feedback system while the Mammalian Diving Reflex could be considered a negative feedback system.

It’s not the first time I’ve wondered about Positive Feedback in a biological sense in open cold water swimming. Previously I considered that the Habituation/Acclimatisation process in cold water swimmers could also be a positive feedback system.

The simple process of improving cold ability
The simple process of improving cold ability

In Systems Theory (and elsewhere) a Positive Feedback System is where a small change causes a further bigger change. Therefore positive feedback is often considered a de-stabilising process. One example might be the international banking system that led to the 2008 collapse: Increased risks led to larger profits which led to larger risks until the system collapsed. However positive feedback can also be a process for change or improvement: If you swim more, you get fitter and able to swim even more, i.e. the training effect. Or the more you get in cold water, the better you get at getting into cold water.

Negative Feedback is often considered a stabilising process, the most common example is a thermostat which regulates heats by switching off when it gets too hot, switching on when it gets too cold: Negative Feedback acts in the opposite direction to the initial impulse.

Cold Shock Response is the bodies response to sudden cold water immersion. It results in varying degrees according to the person’s habituation experience, primarily in elevated heart rate, and elevated stress hormones. It is the elevated heart rate which is dangerous, to lesser extent in the increased chance of cardiac arrest, but more commonly in the chance of aspirating water due to shock and subsequently drowning. Less habituated or experienced swimmers will note an increased heart rate and nervousness even before immersion occurs if they are expecting the cold. I noted some years ago that the first time I ever swam during winter without a wet-suit, I was literally terrified beforehand. Then the initial cold shock drives the heart rate higher. This is a limited example of Positive Feedback, where the initial is destabilised by something (cold) that acts on the input.

The Mammalian Diving Reflex is another innate biological response to immersion. As the name implies all mammals exhibit this, human to weaker extent, but it exists to extend the time that animals can survive while submerged by reducing the need for respiration. This occurs in swimmers through two main biological reactions; decreasing heart rate (brachycardia) and therefore slowing the buildup of carbon dioxide in the body, (as excess carbon dioxide is what cause us to have to breathe); our constant companion, peripheral vaso-constriction, where the capillaries and blood flow in the extremities is restricted to allow more oxygenated blood to be available to the heart and brain.

The Mammalian Diving Reflex is initiated when the fact is submerged, and this is the reason I have previously written many times that you should splash your face before getting in the water, rather than the incorrect but widely cited slashing water down your back.

The Mammalian Diving Reflex is obviously a case of Negative Feedback, where the body reacts in opposition to submersion to protect itself.

So we can see that there is both positive and later negative feedback in operation in cold water swimming, where the negative feedback occurs to stabilise and protect a human through adaptive physiological response. But the initial negative feedback of Cold Shock is very significant and should not be ignores, as so many non-cold water writers seem to do, as it carries its own significant risk factor.

The bottom line though, is that this is another way of saying, that ability in cold water swimming improves with repetition. Habituation improves much more quickly than Acclimatization. In a little as four to five repeats, people become much more comfortable with getting into cold water.

Now get out there!

Cold Water Swimming Articles Index

Snow & Ice on the platform
Once you’ve swum during snow, you’re a true cold water swimmer

This post is an index with a very brief explanation of each of the specifically cold swimming related articles I’ve written, so one can scan the entire list for what is most relevant for their question or area of specific interest.

I was a bit surprised to see just how many I’ve written.

Articles sometimes tackle a similar area from a different angle, some focus on one small aspect of the cold-water swimming experience. This is a body of articles with which I’m quite happy.

If I could impart one simple message, it’s this:

Cold water swimming is dangerous, difficult and requires repetition to improve. No-one does it naturally or easily and knowledge is your ally.

By exploring the many aspects of cold; environmental, physiological and psychological, I hope to help you understand cold better and therefore become a more confident cold water swimmer. These articles therefore are intended to help swimmers adapt to cold water swimming.

It is really important to repeat that most of us are not naturally good at tolerating cold. (I certainly am not). Cold should be seen as something you train for, the same as any other aspect of your swimming.

The Ten Commandments of Cold Water Swimming. I am a prophet of cold water! :-)

The Golden Rules of Cold Water Swimming. For when Ten Commandments are too much.

Loneswimmer returns from the sea, with the commandments of cold water swimming
Loneswimmer returns from the sea, with the commandments of cold water swimming

Habituation. The process of getting used to getting into cold water. This is where it all starts and was therefore the first cold water swimming article I wrote.

Acclimatization. the process of developing tolerance for staying in cold water.

Introducing a Precise Open Water Temperature Scale. This site’s most popular article.

The Reverie of Cold. What I consider the best article on cold or maybe ever, that I’ve written.

“What temperature of water is too cold to swim in”. The most common search term leading into this site.

“What temperature of water is too cold to swim in” Redux. An updated version of the above post with a fuller list of factors affecting the answer.

I just can’t handle the cold“. Part 1Part 2 (What is the Vagus nerve and why is it important?), Part 3 (Fear). This is a phrase I hear a lot. Why this belief is irrelevant and why you, or I, are not special when it comes to cold.

WHY would anyone swim in cold water? Trying to answer the LEAST asked question about cold water swimming.

One of my hypothermia experiences. It happens to us all. That’s part of the deal.

Cold water and cold immersion shock, the first three minutes. It’s really important to understand what happens the body in the vital first few minutes of swimming in cold water.

The Worst Three Minutes. A not-often acknowledged aspect of cold water swimming.

How To: Prepare for cold water swim. Practical precautions around cold water swimming.

Prepare, Monitor, Recover. A short article on part of experienced cold water swimmers’ ethos.

Men, women and cold. Understanding gender differences in cold water exposure and tolerance.

Brown Fat vs. white fat. Interesting and very relevant recent scientific findings that have direct relevance to cold water swimmers.

Brown Fat. A revised version of the previous post.

Merino wool, my favourite cold weather clothes for per & post swimming.

The cumulative effective of cold water swimming. How it feels to swim in really cold water for many consecutive days.

Six hour swim in sub-eleven degree water. The second toughest swim I’ve ever done.

Christmas and New Year’s Day swim advice. Comprehensive advise for irregular swimmers in cold water. Applies to any irregular swims and swimmers.

coldExtreme Cold Water Adaptation in Humans. A five-part series trying to tease out all the various factors  of cold adaptation: Part 1 Asking the questions about individual variability, Part 2 (habituation and acclimatization), Part 3  (metabolic responses), Part 4 (further physiological responses), Part 5 (conclusion).

How we FEEL cold water. Concerning the body’s thermo-receptive response to cold water.

Always wear a belt. A lesson learned (and sometimes forgotten) about cold water swimming.

Peripheral vaso-constriction. The bodies primary physiological response to cold, in picture.

Wearing a watch. The primary safety device on cold water.

The important of stroke and the deficiencies of Total Immersion type swimming in cold water. Following the wrong advice for cold water is dangerous. Stroke rate is very important.

“Is the water too cold to swim”? Another different take on this popular question.

Winter. I like it. I hate it. The dichotomy of a cold water swimmer’s thoughts.

Come with me on this cold water swim. As close as I can take you to my experiences of swimming in cold water during the Irish winter.

Cold water swimming and the Second Law of Thermodynamics. Another experiential post of cold water swimming, with some musing.

Understanding the Claw. What is the Claw and why do cold water swimmers get it?

“Where did my Claw go?”  Further discussion on the Claw amongst experienced swimmers, the Claw being a common occurrence for cold water swimmers.

How To – Understanding Mild Hypothermia in swimmers. To address hypothermia, it is best to understand it. Mild hypothermia is more common than not amongst cold water swimmers.

How To – Understanding Moderate and Severe Hypothermia in swimmers. There’s nothing moderate about Moderate hypothermia.

How To – Diagnosing and addressing Moderate Hypothermia in swimmers. Understanding cold for support crew.

Speaking as a Coldologist… Analysing (and debunking) a claim to cold adaptation through meditation.

Cold water swimming and alcohol. They don’t mix and are a dangerous combination. This is important.

Ice Miles: My First Attempt, Part One (The swim). My First Attempt, Part Two (Post swim and analysis). My Second Attempt. Ciarán Byrne’s report of the successful Lough Iochtar Ice Mile.

What is Cold Water Diuresis in swimmers? Another physiological response to cold explained.

The relevance of shivering in cold water swimming. Yet another important to understand physiological response to cold.

The Magic Number. A consideration of transitional temperatures in cold water swimming.