A timely reminder to be careful swimming through the Winter.

From: Editor’s Blog | Simon Griffiths | H2Open Editor |

“If you have spent any time hanging around open water swimmers you may have heard the term “after-drop”. If you’ve done any swimming in cool water, you may have experienced it. For the uninitiated, after-drop refers to the decline in your core body temperature after you have got out of the water.

When you swim in cool water the body cleverly tries to protect vital organs by reducing blood flow to the skin and limbs. Thus the core stays warm while the skin, arms and legs cool down. The process is known as peripheral vasoconstriction. Shortly after you exit the water, peripheral vasoconstriction ends. Cold blood from your limbs and skin returns to your core where it mixes with warmer blood thereby causing your deep body temperature to drop, even if you’re warmly dressed and move into a warm environment. This is why you often only start shivering 10 to 15 minutes after leaving the water.

It’s a good theory, but can it really be true that your core temperature keeps falling for quite some time after finishing swimming? Last week I had the chance to find out when I took part in a study at the Extreme Environments Laboratory at Portsmouth University. For the experiment I had to swim in cool water (16 degrees and 18 degrees) for two hours while the researchers monitored (among other things) my deep body temperature. After two hours at 18 degrees my body temperature had dropped by about half a degree. I towelled off, dressed, put on a coat and hat and drank a hot tea. I was then able to watch my temperature fall to just over 36 degrees before it stabilised and then started climbing back up. The same thing happened at 16 degrees but the effect was greater, the minimum temperature lower and the time taken to stabilise longer. After-drop is real. While your average body temperature may be increasing, your core will be cooling.

What to do about it

• 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.”

If you want to learn more – and if you’re swimming in the Winter, you should learn more – get a coffee and spend some time on Donal Buckley’s blog www.loneswimmer.com – the bible of cold water swimming.

A few cold people have been asking those of us stylishly attired in our Surf-fur parkas where to get them.  Since there isn’t a local stockist, they have to be ordered online (note: business opportunity for Jellyfish or The Edge!) .

The owner of Surf-Fur, Zenon Issel, was in touch via LoneSwimmer.  They have discounted pricing for orders of five or more.  I’ve already got mine, but I’ll be happy to co-ordinate an order if people want to contact me.

XXL and XXXL Waterparkas are an additional $20 each.  

Shipping cost is $25 per item.

Details on all the products are online here.

I love mine, both the parka and the hoodie – my best buy in a long time!

Interesting comments around at the moment about the fact that the sea temperature has actually been warmer than it was at the start of July this year (12.1c said the Ballycotton gauge…hmmmm: working?).  Even if it’s right, people are saying they feel  very cold in and out of the water.  It’s the air temp combined with the sea that’s the difference, of course.  Spending an hour in the sea (or even 30 minutes) in July is very different to doing it in December, January etc.

Cork Harbour Weather – @CorkHarbourWX – had this on a tweet spotted by Bernard Lynch last week “The still air temp is +6C but the THSW temp (how it actually feels outside) is only +2-3C. Wrap up!”.  Extensive research was then conducted (he Googled THSW) to find what it was:

THSW Index uses humidity and temperature to calculate an apparent temperature. In addition, THSW incorporates the heating effects of solar radiation and the cooling effects of wind (like wind chill) on our perception of temperature.

Why bother posting this?  Just another reminder / warning to us all to think of all the factors when swimming in Winter.  Tides, sea temperature, wind temperature etc.  Cold always wins.  We can go into the sea on a beautiful flat calm day in December and be tempted to go a bit further than we should.

One thing you’ll notice is that a Northerly wind makes Myrtleville nice and calm.  Even quite strong Northerlies can still leave our favourite beach very swimmable.  It’s also a very cold wind!  It’s safer to be five or ten minutes from the beach when you feel cold, than to have gone over past the Dutchman when you realise that wind is freezing your elbows, your hands have clawed and it looks like a long way back.  No rule says you have to go to the Dutchman.  Fennell’s Bay is lovely this time of year!

So, look at the sea, check the tides, agree with a swim partner what you’re doing, cut it short if you feel cold – or before you feel cold – and always have your gear ready for a quick dry and change afterwards.  Afterdrop can be painful and it’s worse if you dawdle getting dressed.  Winter swimming is fantastic – a real buzz.  Just be careful.  Swim Safe.

Siobhan Russell got this beautiful picture yesterday morning.  The sea is under 10c and closer to 9c at times, but the calm conditions have been a bonus.

Heading for the Dutchman – Myrtleville, December 4, 2014.

Not looking as good for next week, but we’ve got 08.15 tomorrow and the Turkey Swim on Sunday at 11.00 to look forward to before then.

As an add-on to the post on swimming in cold water, Donal Buckley has done a great post this week on what to expect as you swim in the colder sea for the coming months and how the blood flow to the limbs and skin is restricted.  Peripheral vasoconstriction it’s called, but he makes it easy to understand!

Swim Safe.

This is even better than the Ballycotton one and – once again – was found by Ian Venner.  Good man, Ian!

Sea temperatures and a lot more from NMCI, Ringaskiddy.

Hours of endless data and fun.  Denis Condon said there was ten swimmers this morning and it felt very cold.  But what does the data from the NMCI say?……It says about 7.8c.  Denis was right, that’s getting lower.   A great service from the OPW.