Think about that water temperature!

The risks from cold water are covered in full detail in book two of the SUP SAFETY series, and if you’re likely to be paddleboarding in a cold water environment then we’d strongly urge you to read that chapter because there’s a whole lot more to the subject than just the risks from cold water shock.  However, for this blog we’ll just concentrate on that initial shock phenomenon and its implications for your safety equipment choices. 

Cold water shock (CWS, also known as cold shock response) is an automatic response from your body to immersion in cold water. You gasp, your heart rate suddenly spikes, you can experience hyperventilation, vertigo, rapid blood pressure changes, head pain or pressure and a variety of other extremely compromising physiological effects. And unlike most of your body’s natural survival mechanisms, these automatic responses are really not helpful. The gasp reflex in particular is utterly inappropriate – if you gasp while underwater and fill your lungs with cold water, you’re quite likely to never come up again! At its most extreme, the sudden increase in blood pressure and extra load on your heart can result in cardiac arrest, even for otherwise healthy adults. So let’s be in no doubt about this – CWS is something you need to take seriously. 

Provided you haven’t gasped your lungs full of water or suffered a cardiac arrest, the essential trick to surviving CWS  is simply to wait it out. The symptoms usually last no more than a minute. So if you’ve fallen off your board, if you can’t instantly get out of the water (always the best option), just hold on to your board until you feel normality returning. Don’t panic – you are not dying. The symptoms will pass. This is NOT hypothermia. (That won’t arrive for half an hour or more, even in near-freezing water.)

Everyone reacts differently to CWS. Some people have a worse reaction in 15°C (59°F) than others may do in 5°C (41°F) water.  Indeed, you can train your body to acclimatise to CWS, by swimming regularly in cold water. However, one of the main triggers of CWS is not so much the water temperature itself, but the difference between the water temperature and your skin temperature at the moment of immersion. So if you fall in during a strenuous paddle session, the odds of a significant CWS reaction are definitely increased, and this also raises the water temperature threshold at which CWS is a risk. Remember also that deep water is often a whole lot colder than the water around the edge of the lake or along the shore, particularly if you penetrate below the surface layer. 

Another significant factor is whether or not your head goes underwater. There are lots of cold receptors on your head and face, and subjecting these to cold water can greatly increase the severity of the CWS reaction. 

So how can we combat the risk of CWS while paddleboarding? You’ve essentially got two choices:

Dress for the water temperature, and wear neoprene or a drysuit so that if you fall in, you’re not going to get fully wet. 

Wear a permanent-flotation buoyancy aid, which will make it much less likely that your head goes under water, and will keep you afloat if you are incapacitated by the CWS response.

The majority of paddlers opt for the second option, but this isn’t always the smart choice. This is the ‘ambulance at the bottom of the cliff’ approach, as discussed in book one of the SUP SAFETY book series. You’ve made the decision that you’re going to suffer CWS if you fall in, but your buoyancy aid will help you survive it. That’s putting a whole lot of responsibility onto your buoyancy aid! (And of course, it won’t save you if you did have a seizure or cardiovascular incident, and end up face down in the water). 

Dressing for the water temperature is definitely the smarter plan, but for sure, it’s less comfortable on a hot day, and less ideal for energetic paddling. A relatively thin long john is a good option in these conditions. You don’t actually need a whole lot of thermal protection to take the sting out of CWS. 

For maximum protection, dressing appropriately and wearing a permanent-flotation buoyancy aid will always be the safest option. 

The other factor worth considering, particularly if you think there’s a high likelihood of falling in (maybe you’re going out to practice step-back turns or some other trick), is pre-acclimatising. Get your body and head wet first in shallow water, and get through the initial CWS response,. Enter the water slowly, and splash your face, arms and chest before submerging to trigger those cold receptors. Let your breathing return to normal before you go paddling, which may take a couple of minutes. And then, if you do subsequently fall in, it’ll be a whole lot less harsh second time round (if indeed you get any reaction at all). 

So, the two big takeaways from this are:

Be aware of CWS. Think about the water temperature before you go paddleboarding, and make decisions about what you’re going to wear and what buoyancy aid you’ll be using. 

Don’t just rely on your buoyancy aid to keep you safe. Remember the fourth golden rule of safety equipment; don’t let it lull you into a false sense of security! 

Finally, remember the other really important cold water survival tip. Don’t BE in cold water! CWS is only the first stage of the process whereby cold water messes you up, lurking ready to pounce if you remain the cold water is loss of muscular function and ultimately, hypothermia. So the best policy is always to get out of that cold water as quickly as possible. You really do not want to get separated from your board in a cold water environment.

Much more on all this in book two of the SUP SAFETY series, while book one goes into much more detail on buoyancy aids, leashes, wetsuits and all the other items of safety equipment, along with a full explanation of the four cornerstones of paddleboarding safety, and the four golden rules of safety equipment.