Water Temperatures

[Wildswimmer]

Most folk, myself included, would find an indoor pool heated to, say, 21C (70F) distinctly on the chilly side.

Yet to experienced open-water swimmers, 21C is pleasantly warm when in a river or lake. Is this down to the "Lewis Pugh effect"? The prospect of swimming in what we anticipate to be chilly water causing a change in one's metabolic rate and perception of temperature?

During July, I found my local river, the Weaver, far too warm at 26C - that's just 1C below the minimum recommended for public pools. Now that the river has dropped back to a more tolerable 22C I've been able to resume training in it without ending up knackered after 15 minutes. Yet in winter I can swim for hours in an indoor pool at 30C. (I was going to put "happily" but there's the chlorine and getting tangled with other swimmers :( )

Any sports physiologists out there?

Pete

[Immy]

Interesting point, Wildswimmer

last weekend I had a dip in the sea locally, and did the usual wimpy thing of one-toe-at-a-time, putting off the evil moment when the waves crept up towards the sensitive bits and cursing most inappropriately on a family-resort beach :aarrgghh:

but once I got in, it seemed OK :) then when I was heading home, and saw a beach lifeguard, I asked if he knew the temperature.
'21 degrees' he replied.
'I mean the water temperature' I said
'That is the water temperature'

that surprised me - it didn't feel in the 20's!

[Wildswimmer]

Here are my latest temperature readings:

http://hometown.aol.co.uk/wildswimmer007/2006watertemps.htm

New Brighton is on the Mersey estuary, and Thurstaston is on the Dee estuary. Tor Bay and Hoylake are on the Irish Sea coast.

All other locations are inland rivers and lakes. Hatchmere is located in Delamere Forest, Cheshire.

Henleaze and Tor Bay readings provided by other swimmers.

Mine are all surface readings taken using a digital thermometer with a known error of -0.5C. I also take readings both surface and at 1m depth using a slightly less accurate swimming pool thermometer (not just dipped in - I go into the water with it), together with the time and ambient air temperature at the location. These are used for my own purposes, but should anyone want the raw data I'd be happy to supply it (probably in .doc format) at the end of the outdoor swimming seaon. Although in my webspace, the temperature table is intended to be part of the RALSA website, and I update it every week or so. I've got the past fortnight or so's readings to enter this coming weekend.

Wildswimmer Pete

NB My first bare-skin (trunks only) swim of the season was on my birthday: 21/04. Brrrrrrrr!!

[Wildswimmer]

Interesting observation today.

Despite the weather I decided I couldn't face chlorine just yet so went down to my usual swimming spot in the R. Weaver (Frodsham, Cheshire).

Water temperature in mid-stream (17-foot depth) was nearly 20C and felt far warmer than the howling NW gale (I did have to remind myself this was still summer). This is despite the fact that the air temperature was around 16C.

Now we are continually being told that water is twenty-five times more efficient at removing heat from the body than air. I wonder why then, the river water still felt much warmer than the wind did on my DRY body before I went in? And the windchill was quite severe when I climbed out of what still felt like a warm bath even after some 2 hours immersion!

The wind was sufficient to churn the river into quite a frenzy, with 1-foot waves and even flying spray. In fact I did "widths" bank-to-bank (about 100 feet) rather than any distance stuff.

Anyone else had the experience of open water feeling warmer than the air? Or is this something to do with cold-acclimatisation?

Pete

[RoDeVe]

I take advantage of this really interesting thread to submit you a question: how many OW competitions are there during the season? Do they take place only in lakes or also in the sea? How do you face low water temperature? I'm curious! Here in Italy OW season begins in late may and ends in september, water temperature is never under 20°C... I could not swim in colder water! I'd die frozen! ;)

[GettingFaster]

That silly lot of open water swimmers in the UK don't bother about minimum temps - I think Leppie mentioned a new year's swim he did at Tooting Bec lido where the water temperature was around 6 degrees. Totally barking mad, the lot of them! :joker:

[RoDeVe]

That silly lot of open water swimmers in the UK don't bother about minimum temps - I think Leppie mentioned a new year's swim he did at Tooting Bec lido where the water temperature was around 6 degrees. Totally barking mad, the lot of them! :joker:
Uh don't call them silly, perhaps in a few years I could be one of them!!! :D I really hope that wet suits are admitted, or the braver you are the less you are dressed? :flash:

[NotVeryFast]

I really hope that wet suits are admitted, or the braver you are the less you are dressed? :flash:
You can see a picture of the swimmers getting into the 6C water at Tooting here:
http://www.swimclub.co.uk/forum/showthread.php?t=4627
As you can see, they're not even wearing fastskins!

[RoDeVe]

You can see a picture of the swimmers getting into the 6C water at Tooting here:
http://www.swimclub.co.uk/forum/showthread.php?t=4627
As you can see, they're not even wearing fastskins!

:aarrgghh:

I didn't mean fastskins, but just wet suits used in OW competitions when water is too cold! well I'm really considering the possibility of organizing indoor long-distance competitions! ;)

[OpenNewbie]

Afternoon all :D

6C is cold! really cold! This is my first season open water swimming, doing ok so far. With regards to teperatures tho, is there a rough gide line as to when its really to cold to go in without risking cramp? I take it the colder it gets, it just takes a little longer for you to adjust? I dont realy want to stop for the winter and dont have the spare cash for a wet suit, but dont want to get in trouble at the same time!

Cheers :)

[Wildswimmer]

I take advantage of this really interesting thread to submit you a question: how many OW competitions are there during the season? Do they take place only in lakes or also in the sea?

Sorry - don't know. I don't take part in any form of competition. I just do it for the pleasure of being in the water - alone!

How do you face low water temperature?

By undergoing cold-hardening.

I'm curious! Here in Italy OW season begins in late may and ends in september, water temperature is never under 20°C... I could not swim in colder water! I'd die frozen! ;)

I've just spent a pleasant afternoon in a river at 19C in bare skin. I'm acclimatised down to 10C but want to get that lower this autumn.

Pete

[Wildswimmer]

Afternoon all :D

6C is cold! really cold! This is my first season open water swimming, doing ok so far. With regards to teperatures tho, is there a rough gide line as to when its really to cold to go in without risking cramp? I take it the colder it gets, it just takes a little longer for you to adjust? I dont realy want to stop for the winter and dont have the spare cash for a wet suit, but dont want to get in trouble at the same time!

Cheers :)

It's generally held for swimmers not acclimatised to cold water, that 15C is the lowest recommended temperature for bare-skin. And even when acclimatised it's not advised to dive or jump in below 15C - always wade in. Cold-hardening is done by swimming regularly as the water gradually cools. That way the body has time to grow the open-water swimmer's "insulation": a subcutaneous fat layer, together with other changes to circulation and metabolism.

Cramp - I can't comment. Apparently some people are prone to cramp and others not. I'm not. However I also swim breast-stroke and only use my legs for stabilisation so if they ever did cramp up I'd still be probaly be able to swim. However it's never happened since I learned to swim 42 years ago so it's not something I worry about.

Finally, if you do want to cold-harden, bear in mind that it involves major physiological changes and takes a lot out of your body. As with any rigourous training regime, check with your GP first, and don't force yourself into borderline hypothermia. As soon as you start to feel seriously cold, get out, dry off, get dressed and run around a bit to warm up. And when the water DOES get too cold for you - wear a wetsuit. You can find them very cheaply at the moment as surfers are very fashion-conscious and unload the current season's stuff so they can buy the latest after Xmas. My Bodyglove Apex Pro Titanium wetsuit cost me £25 on Ebay - they are nearly £200 new!

And remember - the trick is to keep swimming regularly outdoors. Don't stop now then try again at the beginning of October! Don't worry if you also swim in a heated pool, it doesn't seem to intefere with the cold-hardening process.

Pete

[Leprechaun]

Afternoon all :D

6C is cold! really cold! This is my first season open water swimming, doing ok so far. With regards to teperatures tho, is there a rough gide line as to when its really to cold to go in without risking cramp? I take it the colder it gets, it just takes a little longer for you to adjust? I dont realy want to stop for the winter and dont have the spare cash for a wet suit, but dont want to get in trouble at the same time!

Cheers :)

6C is a bit on the mad side, and I as said on the original post races were short and safety was taken care of. You might look at the CSA (Channel Swimming Assocn) and CS&PF (Similar but different!) websites for training tips on adapting to cold. But W-S Pete is right, you have to keep going as the temperature drops. I have no idea what this is like but will be trying to get myself to Tooting this winter to see what sustained cold is like and how one builds up resistance.

There is no need for martyrdom, only do what you can safely cope with!

[OpenNewbie]

Thanks for the advice guys :D

I am well chuffed, i swam the forth today as part of the forth race! I was a fair bit slow and swam waaaay in the wrong direction (even swam in to the railway bridge! :eek: ) but i managed it, apparently just under 2.5k!

I did end up borderline hypothermic tho, problem is, is that you dont notice the cold at all until you are out. Perception of time is a little weird, everyone around you seems to move really fast! Regardless i am really pleased i managed it. It was also the longest ive spent in the water so far, so i now have a rough idea of my limits :)

Thanks again for all the help, keeps me on the right side of safety :thumb:


Also if anyone that organised the event reads this - A big thankyou is in order :D

[Wildswimmer]

Thanks for the advice guys :D

I am well chuffed, i swam the forth today as part of the forth race! I was a fair bit slow and swam waaaay in the wrong direction (even swam in to the railway bridge! :eek: ) but i managed it, apparently just under 2.5k!

Fan-bloody-tastic!! That'd be an achievment for a seasoned open-water nutter.


I did end up borderline hypothermic tho, problem is, is that you dont notice the cold at all until you are out. Perception of time is a little weird, everyone around you seems to move really fast! Regardless i am really pleased i managed it. It was also the longest ive spent in the water so far, so i now have a rough idea of my limits :)

It's unlikely you did go hypothermic as if your body core temperature had actually fallen you'd feel absolutely rotten for a couple of days. Bit like a dose of 'flu so I understand.

Your perception of time was probably affected by endorphins - opiate-like chemicals released in the brain when the body is put under stress. These are responsible for the amazing feel-good "buzz" that can become addictive. I suspect the endorphin kick to be one reason we cold-water masochists do what we do, and "they" can't touch you for it!

Last Autumn it got so bad I was craving my bare-skin immersions in a R. Weaver between 10C and 15C. Felt great afterwards though :devil:


Thanks again for all the help, keeps me on the right side of safety :thumb:

A pleasure. The more of us the better. Have you checked out the RALSA site:

http://www.river-swimming.co.uk

One important point - always wear a swim cap outdoors, especially if like me you have a shaved head. I went for a lake swim last night (water temp 18C - I'd measured it earlier in the day) but was too lazy to dig my cap out of my backpack. Certainly noticed it in the chill evening air. Warm body in warm water - cold head. You lose a good proportion of your body heat via your head.

Mine is an Aquasphere Glide - the one that covers your ears.

Wildswimmer Pete

[OpenNewbie]

Thanks :D

I must have just had a good kick of Endorphins cos i dont feel bad at all :) Totaly loved every minute of it and cant wait for next year. There is a 750m open water swim followed by a 5k run in a couple of weeks, hoping to get in to that. Only prob is, they say a wetsuit is manditory! we will see!

I have a couple of swimming caps as you suggested. Nice bright ones as well so you can see me drown :p

If i get home from work in time, a swim and run tonight may well be in order :)

Cheers for the support

Martin

[Wildswimmer]

I've just updated my 2006 water temperature page:

http://hometown.aol.co.uk/wildswimmer007/2006watertemps.htm

Interesting to note that at the end of September water temps in NW England are still just in the 60s F

Rather shows up RoSPA's claim that "open water in the UK never warms up" for the tripe that it is. I wonder do their water safety "experts" know what a thermometer is, and which end you actually stick in the water!?

Wildswimmer Pete

[Leprechaun]

Interesting to note that at the end of September water temps in NW England are still just in the 60s F
you actually stick in the water!?

Wildswimmer Pete

Apparently we had about 14-15 degrees in the Tooting Bec Lido on Saturday. A 100 x 100 length swimfest- some 2 and 5 person relays, some individuals plus a 100-person relay in parallel. So warm that one lady member didnt even need her cossie....Champagne and birthday (Happy 100th to the Lido) cake afterwards made it all very civilised.

For those who get a real kick out of low temperatures, they (SLSC) have reissued the temperature details from the cold water meet in January. Apparently it was 3 degrees (not the group) not six as we were told on the day...

Tooting now closed ( I think) till Christmas day for some refurbishment

[ruthcp]

I've just updated my 2006 water temperature page:

http://hometown.aol.co.uk/wildswimmer007/2006watertemps.htm

Interesting to note that at the end of September water temps in NW England are still just in the 60s F

Rather shows up RoSPA's claim that "open water in the UK never warms up" for the tripe that it is. I wonder do their water safety "experts" know what a thermometer is, and which end you actually stick in the water!?

Wildswimmer Pete

Perhaps they haven't been sticking in the water.....? :eek: :devil:

[whiteminiman]

It's unlikely you did go hypothermic as if your body core temperature had actually fallen you'd feel absolutely rotten for a couple of days. Bit like a dose of 'flu so I understand.

Never had the flu. But I've suffered from hypothermia three times. Twice very mild. Once moderate. I contracted it the Saturday afternoon, had to work Sunday (but stayed dry and wore every item of clothing I had with me and still felt terribly cold). I went to bed on Sunday night in a sleeping bag, under a duvet, under a hypothermic reflective blanket, in a warm room at about 8pm. I didn't wake up until Wedneday 11am. I then had a MASSIVE wee!

Trust me. There's nothing like hypothermia! It's not just shivering for an hour or two after you get out of the water.

Regards, WMM

[Wildswimmer]

Went swimming in Hatchmere yesterday, and despite it being early October, the water temp out in the lake was 15C (59F) - 13.9C in the shallow bay.

Until I started recording water temperatures I'd always assumed that once October arrived it'd be too cold to swim outdors. All those Autumn swims I've missed because I took notice of the calendar rather than use a thermometer.

Wildswimmer Pete

[Speedy Gonzalez]

[QUOTE=whiteminiman;69326] I contracted it the Saturday afternoon, had to work Sunday (but stayed dry and wore every item of clothing I had with me and still felt terribly cold). I went to bed on Sunday night in a sleeping bag, under a duvet, under a hypothermic reflective blanket, in a warm room at about 8pm. I didn't wake up until Wedneday 11am. I then had a MASSIVE wee!


This sounds like you were in a coma!! Wasn't anyone worried about you? Where/how long/what temperature were you swimming in?

Touch wood I've never had hypothermia - teeth chattering and shivering for a hour after coming out, yes, but I think what you describe is quite frightening. :doctor:

[Wildswimmer]

Just done about 1/2 mile in the R. Weaver (Frodsham) this afternoon - in water at around 15C. Not bad for nearly mid-October, and I got about half an hour's sunbathing on the jetty afterwards.

Needless to say I was just in Speedos - no wetsuit! If only the rest of the winter could be like this.............!

Wildswimmer Pete

[Wildswimmer]

Water temp in the Dee estuary off the Wirral yesterday: 15.9C (nealy 61F). However current weather models are all pointing to the first cold snap of the winter late next week.

So make the most of our extended summer, lads - looks as though we may shortly be in for a bit of a shock, particularly in Scotland. A pity, because I prefer the chlorine in my swimming water to be combined with sodium.

Wildswimmer Pete

[e-fitz]

Needless to say I was just in Speedos - no wetsuit! If only the rest of the winter could be like this.............!

Wildswimmer Pete

Speedos? - Pah! - at the Tooting Bec 10,000 yard relay recently one swimmer took her turn wearing just the obligatory hat and goggles. Despite water of 16 degrees, she wore no wetsuit or swimsuit, just her birthday suit - much to the delight of around half of the spectators.

Unfortunately most of the Lidos and open water venues are now closed for the winter, even though it still feels very warm, and so I am obliged to count laps in a pool until the spring... but shall do the Solent New Years Day dip without a wetsuit in preparation for the Cold Water champs in January.

[Wildswimmer]

Hatchmere Lake today, 14C. And I had several bare-skin swims, much to the astonishment of anglers and bystanders.

Well, I take note of the thermometer, not the calendar. :)

Wildswimmer Pete

[Wildswimmer]

Well, it's now approaching late October, and you'd think open water would be on the chilly side. I went for a swim in the R. Weaver today and was somewhat surprised to find the water temp in mid-stream to be 16.5C at the surface. Temp at 1m depth was the same, but you often don't find a well defined thermocline (the sharp transition between water layers of differing temperature) in rivers due to the mixing action of turbulant flow.

This beats last year's record Autumn water temperature by more than 1C. Yet more proof that global warming is here?

Definitely makes a mockery of RoSPA's claims that "open water in the UK never warms up". Rather the opposite: it's showing a reluctance to cool off.

Oh, regarding the much heralded "cold snap". Well the GFS weather model had got its knickers in a twist over the positioning of that large complex low sitting to WSW of the UK. The unsettled but warm weather now looks set to continue at least to the end of the month. This October is heading for the record books with a CET (Central England Temperature) anomaly of +2.2C so far.

Wildswimmer Pete

[Wildswimmer]

And the swimming goes on: today bare-skin for 20-30 mins in the Dee estuary on Wirral. Water temp at high spring tide, 12.6C (54.7F)

The way things are going I'm looking to beat last year's pb which was bare-skin in the first week of November.

Wildswimmer Pete

[Wildswimmer]

......and again despite the clocks going back last night! Two 30 min sessions in the Irish Sea at Llandudno and Rhyl (N. Wales), water temp around 13.5C (56F).

I hope to post some pics taken on my waterproof camera in the "Places You have Swum" thread later on.

Wildswimmer Pete

[OpenNewbie]

After seeing the lastest pics in the Pics of Places you have swam thread, i am a little jelous! It was in the minuses here last night and forecast for -4 tonight, not up for getting in the outdoors water now!

[Wildswimmer]

After seeing the lastest pics in the Pics of Places you have swam thread, i am a little jelous! It was in the minuses here last night and forecast for -4 tonight, not up for getting in the outdoors water now!

The current cold snap might chill inland waters but it's unlikely to affect deep sea temperatures all that much. So if you try a swim in seawater that's just come from deep water (as I was at Crosby) you could well be surprised.

Current indications are that the cold snap will finish over the weekend with a return to mild conditions. Put it this way - I haven't given up the prospect of more bare-skin sea bathing this year, although I'd think twice before going in inland water without my wetsuit.

Wildswimmer Pete

[Wildswimmer]

Managed to beat my personal best from last year (Bare-skin on 2nd Nov in water at 13.5C).

Did about twenty minutes today in the Dee estuary off the Wirral. Water temp 10.3C. I could have stayed in longer but the tide was ebbing rapidly and I ran out of sufficient depth to swim. Taking into account last week's cold weather, and the chilly night last night I was not expecting to swim tday. But a mild, sunny day was sufficient temptation and I'm glad I did.

Wildswimmer Pete