Friday, 20 October 2017

Cold Water Shock- making myself aware of the causes, symptoms and responses.

I've recently decided that I'd like to continue swimming in the open water into the winter (not continually like Forrest Gump, 'cause that would be just too exhausting!), but even before I've even put a toe in the cold water, a good friend, who is always one to put the fear of God into you if she thinks you are being an idiot/stupid/risking life and limb, has already had her two penneth. She appears to be well versed to the dangers of cold water. Impressed, I enquire as to how she had become such an expert in the field. She admitted that she's quoting the RNLI's advice about the dangers of cold water to me having recently been on an educational visit and, well, (her words) "some of it had sunk in. I knew I'd need it one day to lecture my idiot friend who has no sense whatsoever! Why would you want to do it?"

Why indeed? Swimming in cold water is potentially dangerous, and up until now I have spent all the winter months almost surgically attached to my hot water bottle, so I'm really not sure, but I know I am waiting, with almost excitement (could be fear, they are said to be closely intertwined), for the water to cool down, and it seems I'm not alone, cold water swimming is fast becoming more and more popular, with many swimmers not only enjoying the cold water, but also claiming to have felt both physical and mental health benefits from it. There is, as of yet, only a small amount of scientific evidence to back this up, but there is more than plenty when it comes to the risks associated with swimming in cold water. 

One of the risks is hypothermia, which I shared with you in a recent blog, hypothermia-what-i-needed-to-know.html. Another, and one that people are far more likely to die from (sorry to be blunt), is cold water shock, which unlike hypothermia, happens as soon as you get in the water. Mike Tipton Professor of Human and Applied Physiology at the University of Portsmouth and cold water survival expert says:

"If you're lucky enough to survive long enough to die of hypothermia, you've done very well; most die in the first minute of immersion." 
I promised my anxious friend that I would read more about cold water and the risks involved and I thought I'd share the information with you, but before I go on please note I'm not a doctor, specialist, scientist, or indeed Guru (unlike my friend), I'm just a swimmer that wants to understand about the dangers, learn how my body will react so I can be better prepared and be able to respond properly, enabling me to enjoy my winter swimming as safely as I can, or worse case scenario, to increasing my chances of surviving. The information below is me just sharing. It does comes from experts, scientists, medical people, accomplished swimmers and organisations, all of which I'm not! These are their thoughts, opinions, recommendations and suggestions. Once again, I must say that some of it may be conflicting, and parts of it that you may not agree with .... Basically, in a nutshell what I'm trying to say is don't shoot the messenger!

Firstly, what is cold water shock?
"It is the body's short term involuntary response to being suddenly immersed in cold water." RNLI (2017)
Our bodies are designed to function and operate efficiently within a very narrow temperature range which the body needs to maintain. If the body's status in quo is altered even just a little bit, it begins a process to return it back. It does this by sending signals to the hypothalamus in your brain (one of it's jobs is to keep your body in a stable and constant condition), via your nervous system. The hypothalamus then generates instructions to return the body to it's equilibrium state, so in the case of swimming in cold water, when your skin is exposed to the cold water, your body triggers immediate physiological responses (an automatic instinctive reaction to a stimulus). 
These responses are collectively known as the ‘cold shock response.' And as cold water carries heat away from your body about 25 times faster than air at the same temperature, the following effects will happen quickly: 

  • Involuntary gasp- this overrides the ability to hold your breath. If this happens and your head is under the water you may drown immediately. One breath is all it can take.
  • You start hyperventilating - (this can be as much as 4-5 times your breathing at rest). The rapid breathing can lead to hypocapnia (this is a deficiency of carbon dioxide in your blood), which can cause: dizziness, visual disturbances, anxiety, numb hands and feet, pins and needles, cramp, onset of asthma, chest pains and slower reaction times.
  • Your heart rate and blood pressure increases significantly, and your heart rhythm may change as the blood vessels in your skin constrict in response to the cold, by shunting the blood away from your limbs to the core, to protect your vital organs- The increased load on your heart can lead to cardiac arrest or stroke. This is most likely you have an underlying heart condition, however it can happen to even the healthiest of people.
  • Your ability to move decreases as the body cuts off the blood flow the the non essential muscles of your body. 
  • Increased levels of the stress hormone adrenaline in your body -  this also increases your heart rate and your blood pressure.
  • Dry drowning - cold water hitting your throat can cause it to spasm to stop any water getting into your lungs. Unfortunately, it will also stop any air getting in. 
  • Your instinct may be to swim hard, however this can lead to drowning as you'll probably be gasping. 
  • A feeling of panic.

I've include here a video link with Ant Middleton, the ex special forces military veteran and ambassador for RNLI, experiencing what cold shock feels like at the University of Portsmouth. It also demonstrated how cold water affects your motor skills, even after only a short period of time. It's an interesting watch. watch

Cold water shock only lasts for a short space of time. For some it will take less time than others - Everyone is different, but it usually passes in under three minutes. The important thing is to try and remain calm, and know that this feeling will pass.

How can you minimise the risk of cold water shock?

  • Don't jump or dive in (that involuntary gasp underwater means you'll inhale water).
  • Try and stay calm and relaxed.
  • Wait for the feeling to pass before you set off swimming  (or if you do, swim with your head out of the water).
  • Float on your back. 
  • Habituate yourself gradually.
  • Keep warm up to the moment you get in- swim coats, hats, gloves, socks, hot drink etc.
  • Do some stretches- it should help you to get into your rhythm quicker.

So, if I am to continue swimming through the winter, what can I do to stop this from happening? The short answer is, nothing. Cold water shock happens whether I fall into cold water, or choose to get in and it will always happen, however there is some evidence to suggest that, if I repeatedly expose myself to the cold water (stimuli) it will result in an increased tolerance to the cold, which hopefully will mean that my response as I become accustomed to it will shorten, and I'll be able to enjoy the water for longer (repeatedly getting used to getting in cold water is known as habituation, whereas acclimatisation is the process of adjusting so you're able to stay in cold water for a longer period of time). I'll write more about these when I've had a bit more experience. In addition to reading about cold water shock and hypothermia (there are also two more stages of cold water immersion) I've joined a winter swim club. I've not swum in water colder than 14oc before now (except once very briefly at 10.1oc but I'm discounting that on the basis that no sooner was I in, than I got out - and not very elegantly I might add. I blame the lack of feeling in my feet and we'll leave it there), The one I joined (Swimyourswim) runs for six weeks and includes training, coaching, safety and advice. It's been great, and really informative. It turns out it's also full of great bakers. It's a lot like GBBO every week so far, and I couldn't be happier about that bit!

With regards to cold water they recommend the following: 

1. Keep warm until you get in the water.
2. Walk in up to your waist keeping your feet on the ground.
3. Hand/wrists in.
4. Splash the back of your neck and face.
5. Dip your shoulders under slowly. 
6.Gradually start swimming once breathing has settled.
7. It can take 200/400 metres to get comfy and swim easily.
8. Never swim alone.

I have to say that as I read back through this blog, it all seems pretty grave, however I really don't see the point in sugar coating it- not if it can save your life, or that of someone you're swimming with. Cold water is potentially dangerous, and as I report back to my friend (who I suspect was trying to put me off by suggesting I read about it), that I've now done the reading, am doing a course and still want to continue. She is not impressed, and now tells me that only a full medical will put her mind at rest (this actually isn't a bad idea. A clean bill of health before I start means that I know that I'm having a normal response to the cold rather than something else. This is also recommended by Leon at SYS and Coach Morg at Blue Lagooners), but I now realise that despite all my promise to be careful, there's actually no pleasing her when she said "This is all well and good but don't come running back to me when you've frost bitten toes!" Er, okay, but should I get frostbite, I'm pretty sure running will be out of the question anyway (I don't say these words, I only think them in my head... Too much like poking the already anxious bear otherwise, and I'm not that much of an idiot)!

Finally, it's a year since I first began writing my little blog, which stared as a way of writing about my recovery, the training and the swim I did last year (Windermere one way). I have been amazed and overwhelmed at the amazing response, and lovely messages of support I have had. After I had completed the swim I was asked if I would consider putting last year’s journey into a book. Going from a blog to an e-book is something quite different, and a lot scarier, however I decided after a lot of consideration to take the plunge (no pun intended) and do it, and finally has now been published this week on Amazon. How amazing (but mostly scary) is that? I hope that for those of you that read it feel inspired to not only take on difficult challenges, but also to never underestimate how far you can push yourself to achieve what you set out to do.

Open Water Woman Swims Windermere is available on Amazon

I also have a "group" on Facebook. Its not really a group, as it's only me, but on it I post more regularly, and I'm also on Twitter and Instagram. You'd be very welcome. Here are the links. 😊

Bibliography and points of reference (in no particular order): (for Coach Morg).

Tipton MJ (1989) The initial responses to cold-water immersion in man. Editorial Review, Clinical Science, 77: 581-588.

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