I stood on the side of the lake as Shark vocalised many excuses and reasons why she should swim in her wetsuit instead. I reaslised she wasn't being serious when they ranged from tooth damage from shivering to the possibility of it giving her trench foot. I diagnosed a case of acute hypochondria and told her to get on with it.
In our inexperience we entered the water with extreme caution, and closely followed all the instructions from Leon, who was standing on the side. He told us we would be fine by the time we got to the first orange buoy, and he was right. I was expecting at best to have ice cream head, and at worst I'd have the shortest swim in history, however was delighted when neither happened.
We swam for 800 metres before Shark began to feel the cold and wisely decided to call it a day. I wanted to complete a mile if possible and after a quick recce (can still I feel my toes? Yes. Are my hands clawing? No.), I decided I'd be okay to carry on. I'd really enjoyed it, and wasn't feeling the cold, so I carried on. I felt great, and when I got out Shark was waiting, holding my towel and Swimzi ready to put straight on (she's a great swim bud), so I could get dried and warm quickly. I dressed, but as I said before I wasn't feeling cold. This is most likely because I had actually spent the second lap trying desperately hard to keep up with another swimmer (in a wetsuit) who at first sight appeared to be going relatively slowly, but in reality he was actually very, very fast, making keeping up impossible, however all the extra effort meant that I concentrated less on feeling the cold and more on the (fruitless) chase, and so by the time I got out I was exhausted and practically hyperventilating, but not cold.
Shark and I had decided to try and swim once a week without wetsuits for as long as we could tolerate the cold. Swimming in cold water is very much unchartered territory. I realised after our swim that I had not really much idea of how my body would respond to the cold, and actually when I should get out. Just checking if my feet and hands were cold or not wasn't at all thorough enough and so I was wanted to find out more about how it will affect me, and Shark, in particular with regards to hypothermia. Shark is the nurse, not me and if I presented the symptoms of hypothermia I'm confident I'd be well looked after, whereas Shark wouldn't be. I think it would bad form to have replace my swim buddy due to neglect, and I'm not entirely sure I'd have many takers if I'm belong honest!
I read loads, and want to share with you what I've found/discovered/learnt. Whilst I usually attempt to make anything I write a bit light hearted, and can pretty much find something (usually me) to poke fun at, when I began looking in more detail about hypothermia it's just too serious, dangerous and important topic to be jovial about. And so...
The next part in this blog has been taken from various websites and people I know. I'm aware that there are various differences of opinion, and some of which some of you will agree and disagree (as some of the websites did) in parts. I'm not an expert, but would like to share what I've found in the hopes that at least one person, other than myself, is better informed, can recognise the symptoms and get medical help and treatment as quickly as possible if necessary. The information I've included is found in the websites, and folks that I know that know far more about it than I do. I've added at the bottom (and not in any particular order - my university professors would not be happy) if anyone wants to read more broadly.
"Hypothermia is a dangerous drop in body temperature below 35C (95F)." www.nhs.uk
"Hypothermia is a medical emergency that occurs when your body loses heat faster than it can produce heat, causing a dangerously low body temperature... When your body temperature drops, your heart, nervous system and other organs can't work normally." www.mayoclinic.org
Although most hypothermia happens in low temperatures I have read that even temperatures as mild as 26oc can still be dangerous, and hypothermia is still a possibility, and whilst the colder the water, the quicker and the more likely you are to suffer (there can be other factors involved), there is no time frame for when hypothermia will set in. None of us are immune, and that includes the most seasoned and adapted of swimmers.
Our bodies work best within a certain temperature range, and it's important to maintain this in order to function properly. Many essential chemical reactions that happen in our body can only happen in this range, so when it alters, our body immediately triggers changes to return it back. This is the function of the hypothalamus, which is found in the brain. It collects all the internal and external information (in this instance temperature) and puts changes in place to right the imbalances, to return the body to its status in quo.
When you are swimming in water colder than you, in order to protect your vital organs, your body begins a process. Blood vessels shunt (moving blood to where it's needed) the warm blood away from your skin and limbs towards your vital organs by reducing the blood flow to your extremities. This allows more oxygen to be delivered where it's needed the most. This is to preserve heat in the important bits. Your body is working hard to try and keep your core at its normal temperature. This process is called peripheral vasoconstriction. It's the body's way of protecting against hypothermia.
"Peripheral vasoconstriction basically means the narrowing of your blood vessels that supply your extremities. This means that your blood vessels in the periphery have constricted and hence bring in less blood so that whatever blood is there in the body is diverted to your vital organs"
(studies at Mysore medical College and Research Institute (2020))
This process stops when you get out of the cold water and your body then sends the warm blood from the core back to the skin to warm up again. The problem though is that it also cools the blood as it does so, as it's now mixing the warm blood with the cooler blood, and then recirculates the cool blood back to the core, meaning that your temperature will drop further. This is known as the "after-drop." This doesn't happen immediately, and when you exit the water you'll probably feel great for a short time. This is because your cooler blood hasn't reached your core straight away, however within a short space of time, you will begin shivering (great piece of advice was to get dressed quickly after getting out, as it's really difficult when you're shivering).
Shivering is one of our body's immediate reactions to generate heat. Our skin sends messages to the brain, which then sets off a series of warming tricks. Shivering is one of them. It's your muscles contracting and expanding quickly to produce heat to raise your body temperature.
As symptoms of hypothermia can happen slowly, you would think that would give you time to get out in good time, however you may not be aware of them as hypothermia can affect, amongst other things, your cognitive ability; your ability to think clearly, and make intelligent choices, which means you may not even recognise the symptoms. Your brain is so sensitive to cold, and electrical activity slows down in response to it, so your ability to do things and move lessens, making it more difficult to take action. I've included a list of the symptoms of hypothermia, that are listed on several websites below, for your reference:
Symptoms of mild hypothermia include:
Symptoms of moderate to severe hypothermia include:
- Get dressed quickly and warmly. Immediately after swimming you may feel great as the cooled blood has not yet returned to your core. Best to wrap up warmly before it does. It’s much harder to dress when you’re shivering.
- Don’t take a hot shower as this will increase the rate at which cooled blood returns to the core and makes the drop faster and deeper. Cold water swimmers have been known to faint in hot showers. Wait until you’ve warmed up again before showering.
- Don’t attempt to drive or ride a bike until your core temperature has recovered. Driving and shivering is not a good combination. If your core temperature drops too much and you become hypothermic it can also affect your cognitive abilities. Again, not good for driving.
- Drink something hot and eat something. Shivering is a highly energy consumptive bodily function. You need to fuel it.
- Keep an eye on your fellow swimmers. Someone who appears completely fine getting out of the water may be in trouble 10 minutes later and may need your help.
- Get out of the water before you get too cold as you will continue to get colder after swimming – give your body a margin of safety.
|Swim bud left, me to the right after our swim|
|Open Water Woman Swims Windermere is available on Amazon|
Bibliography and special thanks to:
Jonathan Cowie @outdoorswimmer for your guidance and help.