OK! So youʼre thinking of trying open water swimming in cold water, or perhaps you are looking at entering your first triathlon, what are the dangers?

Cold Water Immersion

One of the main things to consider, beyond ability and fitness, is temperature and the effects of cold water immersion. Most people have experienced the sensation of walking into a cold sea or stepping under a cold shower. This is called cold shock and will make you gasp. This is a reflex action beyond your control and is OK as long as your head is out of the water, because if your head is underwater you could aspirate water and may drown. Other things happen to your body including an increase in heart rate and blood pressure. Your system will begin to stabilise after a few minutes but you may continue to shiver and the water will begin to cool your
body temperature.

If your face gets wet another reflex may come into play and this one wants to slow the heart rate and lower blood pressure, in preparation for diving.

Autonomic Conflict

If the two reflexes occur at the same time you have something called ʻAutonomic Conflictʼ and cardiac arrest is possible, especially if associated with mass start and/or competitive events.

Thatʼs the bad news! So what can we do about it? Firstly, avoid sudden and total immersion like jumping or diving in before a swim, even if you think it is warm enough. Enter the water gradually and keep your face out until the initial effects of the cold have stabilised.
Keep a log of your total swim times, the water and air temperature and how you felt after. Use this log to judge training times to the changing conditions. Swim and train with someone, not alone. Swim somewhere with lifeguards or some form of safety cover. If you
are at a race try and get a warm up swim before the start. If you are beach starting, wade in on your way to your start position, before running in. Unless you are a gold medal favourite consider walking in and taking a few minutes to settle. Once underway at a mass start event, remember to keep calm (anger can exacerbate the problems) and above all take full breaths, if you have to turn onto your back or slow right down this is preferable to getting into trouble. Once the chaos calms down you should be able to get into a rhythm and enjoy your swim.

This may all sound a little too dangerous but we need to keep things into perspective. With some insight and a few simple strategies we can increase the enjoyment and lessen the risk.

Information about other open water swimming hazards, please click here.

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