HUNDREDS OF EVENTS will take place all over Ireland today, as people take part in the traditional Christmas Day swim.

There’s been a surge in popularity in festive swimming events in the last few years – with queues of hardy souls forming at locations like the Forty Foot in Dun Laoghaire.

The North and South Bull Walls in Dublin are also expected to be busy today, as people opt to take a plunge after unwrapping their presents.

So why do they do it?

Frank and Clare Hallinan Flood take part in a Christmas Day swim on Low Rock beach in Portmarnock in December 2014. PA WIRE PA WIRE

Obviously, there’s plenty of community spirit on show as people catch up with old friends and neighbours at the events.

As aficionados will attest, winter swimmers often experience something of a ‘natural high’.

Here’s how Tim Moss of the UK-based Outdoor Swimming Society describes it:

“Winter swimmers talk a lot about the ‘high’ they get from cold water – a feeling of wellbeing that’s so encompassing that it becomes quite addictive (who doesn’t want to feel truly good, at least once a day?) The cause? Endorphins.

“Endorphins are the body’s natural pain killers and, in the case of a cold dip, it uses them to take the sting away from your skin. So, to get high on your own supply, all you need to do is jump in a river.

And if you think that sounds dangerously close to the pleasure/pain barrier then you’re probably right. The two other primary causes for endorphin release are pain and orgasm.

Pat Cremin from Wicklow at the Forty Foot in Dublin last year. RollingNews.ie RollingNews.ie

Moss adds:

The cold will also stimulate your parasympathetic system, which is responsible for rest and repair, and this can trigger the release of dopamine and serotonin. These neurotransmitters are a vital part of keeping us happy and low levels of them are linked with depression. Couple this effect with the endorphin rush as you take the plunge and it should make for a warm glow and a wide smile when you re-emerge.

Fans of winter swimming often talk-up other health benefits too: it’s said to boost your immune system, and obviously you’re bound to burn up more than a few calories as you thrash around in the cold water.

Of course, there are also some inherent dangers to take note of… But bear these points of advice from Irish Water Safety in mind and your own experience should pass off (for want of a better word) swimmingly.