Cold water swimming has soared in popularity over the past few years, with many people discovering its joys and benefits during lockdown, when indoor swimming pools were closed. It’s more than a way to exercise, although swimming is hugely beneficial for cardio fitness, strength, suppleness, and stamina. 

The activity of plunging into cold water and swimming for a distance can certainly test the body to its physical limits, but it can also bring other benefits. The icy shock to the system can swiftly be followed by a sense of euphoria, as the endorphins kick in and send those feel-good hormones surging around the body. It may also boost the immune system.

Open water swimming can be practised in dedicated swimming lakes, or at wild beauty spots, in rivers, or in the sea.  Some people wear specialist clothing such as wetsuits and thermal gloves and boots, which can provide some insulation from the cold and extra buoyancy in the water. 

Is there a link between cold water exposure and a stronger immune system?

There is a theory that cold water immersion boosts the body’s immune system by provoking a stress response. Some studies have shown that it can increase the number of white blood cells in the body, which are essential for fighting off pathogens. The raised white blood cell count may be because cold water stimulates the immune system.

Cold water can also stimulate the circulation and boost the blood flow to the vital organs, and regular exposure may lead to long-term improvements.

Repeated exposure to cold water can also help the body to become more acclimatised to dealing with stress, and thus reduce overall stress levels. This in turn may strengthen the immune system, because chronic stress can suppress the immune response. 

It may also be the case that repeated cold water exposure can activate antioxidant defences in the body, which play a key role in immune defence mechanisms.  

Personal testimonials

These scientific theories are backed up by anecdotal evidence of cold water swimmers, which of course cannot be taken as proof, but it does open up intriguing possibilities for future research.

One such swimmer is Amr Madbouly, 34, an engineer living in south Wales who is originally from the rather hotter climes of Egypt. He spoke to the BBC about how cold water swimming is helping to manage an autoimmune condition that has caused him to develop arthritis. It is also improving his mental health.

Amr explains that he has been interested in the Welsh landscape from a young age, which he finds to be a refreshing contrast to the stifling heat of Egypt. He first came to live near the Brecon Beacons in south Wales six years ago, when he got a job at the Tata Steelworks. 

Amr told the BBC: "Somebody who's coming from a very dry and rough desert environment, when you see green it's amazing. It looks like heaven. When you have so much heat and sun in your life you long for cold and you're like, finally, it's colder now. I love it."

He added: "One of my dreams has always been to live near the Brecon Beacons and the Welsh countryside because I always found it very special and so spectacular with all the hills and the mountains and lakes.”

"I found a job in the steelworks and was like 'whoa, that's the one'. I applied for it, got it and we moved to Wales. It's been about six years ago now and I'm absolutely loving it. This place is marvellous. It's an absolute heaven. This is an amazing place to walk, to enjoy the atmosphere. It's fantastic."

He first started cold water swimming during lockdown, and his favourite place is a mountain lake. He said: "You've got to be very mindful and respectful of the cold water because it can be an absolute grace, a healer and be really good for you, but at the same time if you don't know what you're doing it drains your energy really, really fast and that's the risk."

Amr developed a reaction to the Covid vaccine, which triggered an autoimmune response, leading to a diagnosis of arthritis. Instead of accepting the doctors’ recommended treatment of immunosuppressant medication, he decided to embark on a routine of rising at 4.30 or 5am every day to go cold water swimming before work.

His doctors have noted a noticeable improvement in his physical condition without resorting to medication, and Amr is also in much better mental health. 

He said: "I was absolutely devastated because my fingers are swollen, I can't close my fist, I can't walk, my vision is full of black dots. I was struggling with everything, getting dizzy, fainting, the whole system gone upside down." 

"I kept searching and found a crazy guy called Wim Hof [the Iceman cold water advocate], and I started learning all the breathing techniques and the cold water. I was already in cold water before but this is really cold [in an ice barrel].

"I started doing that every single day and I started seeing the change happening every single day. I start going for blood tests and the doctors are seeing change and things are improving."

"I had severe depression and I became so much better in mood. I can't imagine myself not doing this now because every time I'm not feeling well, or frustrated or down, maybe about the job situation, once I get in I'm just somebody else. I come out so happy, smiling, excited about things and that's why I do it.”

This may be anecdotal evidence, but it’s certainly an inspiring testimony to the benefits of cold water swimming. However, anyone trying it for the first time should be wary of hyperthermia, and they should take precautions such as wearing a wetsuit, entering the water gradually, and not staying in the water for too long. 

Sarah A