If we were bolder, we’d be colder - ice bath, anyone?

Cold water swimming is good for body and mind - but it's hard to do.

The perils of thermal monotony.

It’s known as the ice-cream headache. The water is freezing but you have to put your head under. Then the whole body goes in and, even if you are wearing a wet suit, it feels like ice is running down your back.

And if it’s really cold, like 12 Celsius or lower, you worry that your teeth will fall out.

Welcome to cold water swimming, also known as wild swimming. I’m too cowardly to do any more of it than I have to, but I’ve swum in Scottish lochs (reluctantly), English rivers and, in this case for a triathlon, the Olympic rowing course at Eton, near London, in early spring when the water temperature really was 12 Celsius. Officials were relentless – they made us dive straight in.

The issue is whether swimming in cold water is good for you. I’m not sure but I do know that it is mentally and physically rejuvenating. When you get out, that is. However the evidence is mounting that a cold dunk is highly beneficial to your health. Professional athletes hop into ice baths to accelerate the healing of hard-worked muscles. I know people who swim year-round and, although you can hardly call it evidence, they look remarkably healthy to me. One thing you do notice is that wild swimmers tend to have glowing skins.

My hardy late father liked a cold bath most mornings and he lived to 95. However my mother used to soak in hot baths and also lived to 95, so the jury is out.

You’ve probably heard of Wim Hof but, if you haven’t he’s the extremely hardy Dutchman dubbed The Iceman who takes dips in pools full of chunks of ice and climbs mountains wearing just shorts. I’ve watched his videos and he’s adamant that it’s therapeutic in mind and body to get cold. Hof combines this with breathing techniques – “delve into yourself”, he says.

He makes the ice bath at your local spa look like a walk in the park.

A whole science is developing around the benefits of being cold. British health guru Dr Michael Mosley says: “The cold isn’t always the enemy. It is something we can at times work with and harness in ways that can help our health and wellbeing.” British newspaper The Times pointed out recently, our modern centrally heated world may be working against us. Scientists have a brilliant term for it -- “thermal monotony”.

As The Times argues, our bodies are designed not just to acclimatise to cooler conditions but to thrive in them. “When we start to cool, the body prepares to maintain a constant temperature of about 37C through different mechanisms. Initially, blood flow is redirected from extremities — the fingers and toes — to the core and, before the point of shivering, heat is produced internally as muscles contract.”

I’m training up for a half-Ironman – technically known as a 70.3 –and the sea is definitely cooler. I haven’t resorted to a wet suit so far, but I want to keep swimming in the sea for as long as I can because it’s important to get used to the currents, tides and waves. If it gets rough, you need a different swimming technique than in the pool.

A dip is however different from a swim. It’s one thing to wade in up to your neck, another to plough away for an hour or so. I will finish training at Te Anau at the bottom of New Zealand where the water temperature in the local lake is heading towards single figures.

So I’m about to find out if I’ve got the required willpower.

Do you?

[Read what the Mayo Clinic have to say on the matter - maybe you'll be persuaded.]