4 hours agoJames GallagherEmma Lynch/BBCIt is a cold morning in the depths of winter.And I feel like I’ve left my sanity as well as my warm clothes in the changing room as I stride out to the edge of a reservoir in my swim shorts.A brightly-coloured chalk sign informs me that the water temperature today is a chilly 3.9C, as one of the regulars tells me this is not cold water swimming, it’s “ice” water swimming.How did I end up here?Well, I’ve become enthralled by the idea of enhancing or boosting the immune system. My body has been the living embodiment of the “quademic” that the NHS spent all winter warning us about. It’s been a relentless stream of colds and coughs and one explosive tummy.Our immune systems already do a fantastic job fighting viruses and other nasties. If I collected all the air I breathed out over the course of a minute it would contain 100 to 10,000 bacteria, 25,000 viruses and a single fungi, according to Prof John Tregoning, immunologist at Imperial College London.”You’re breathing these things in all the time, there’s just a swirling mass of pathogens [organisms that cause disease] in the air,” he says.But there’s plenty of foods, supplements and activities that are touted for their “immune-boosting” properties. Can we dial up our protection?Can a cold water swim stop you getting ill?Emma Lynch/BBCAnd that’s why I find myself wading out and pushing off for a chilling blast of breaststroke.The icy water is like fire on my skin and all my brain can think of is making it to the pontoon without needing help from the lifeguards.But studies have shown the adrenaline hit of the cold water does flood the blood stream with infection-fighting cells.White blood cells – which could produce antibodies or attack infected tissue – move out of their normal homes and head out on patrol thinking there could be an infection. So does this mean I’m more protected?”Within a few hours that all goes back to normal,” says Prof Eleanor Riley, an immunologist at the University of Edinburgh.”There is no evidence that people who go cold water swimming have fewer colds or fewer infections.”Regular exercise may give you a younger immune systemThere might not be the evidence for cold water, but regular exercise may well do the trick.On average adults get two to three colds per year and children between five and eight, says Dr Margaret McCartney, a GP and expert in evidence-based medicine, at the University of St Andrews.”[But] people who do moderate amounts of exercise tend to report fewer viral infections,” she says.There is a lack of conclusive clinical trials, but the data we have is “all pointing in the direction of it being good for you… but …
