**EP262: What About Cold Exposure?**
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Welcome. My name is Dr. Warwick Bishop, and I'm a cardiologist, an author, a keynote speaker, and CEO of the Healthy Heart Network. I'm all about trying to help people live as well as possible for as long as possible, and that includes heart attacks, which impact Australia enormously. We're talking about a heart attack almost every 10 minutes and over 20 people per day dying from a heart attack in Australia. That's on a backdrop of over 9 million people globally being impacted. The sad truth is many of these could have been averted if only we knew what to do. Well, this podcast is all about that: weight, blood pressure, cholesterol, general health, and driving health literacy. I'm on a mission to help not just prevent heart attacks but improve general health on a global scale. If you enjoy this podcast, I would be honoured if you could give it a five-star review and share it with your family and friends. It may even lead to saving someone you love.
Hi, my name is Dr. Warwick Bishop, and welcome to my podcast and videocast station. Thanks so much for tuning in. Today, I'd like to talk a little bit about cold exposure. Many of us may well know of people who regularly practice cold water exposure, like ocean swimmers, for example, or people who report using ice baths. The practice of cold exposure has been around for centuries, and in certain places, it has included chipping a hole in the ice of the local lake and people immersing themselves.
Well, what's it all about? Why do people do it? And is there any benefit? I came across an article just the other day which looked at a systematic review of over 100 studies in regard to cold exposure. There is no question from this review that there appears to be a scientific basis for consideration of that particular strategy.
What happens? Being exposed to cold alters the way the body responds metabolically. And metabolically, I mean the way the body's processes work in particular. You may not have known this, but the body carries two different types of fat. We have standard white or yellow fat, which is the stuff that accumulates around our tummy if we eat a bit too much and don't exercise enough. But we also have this fat called brown fat, and that brown fat is more metabolically active. Interestingly, we are gifted with much more brown fat when we're younger, and in fact, infants have a lot of it. Why? Well, that brown fat can be so metabolically active that it generates heat.
It makes sense then that cold exposure may turn on the brown fat, the so-called good fat, which will then burn calories and use up energy. It does more than that because it seems to also improve insulin resistance, which is pretty important. Possibly, it shifts a balance within the non-brown fat. Nonetheless, there are people who have been ice swimmers, polar swimmers, plunge pool enthusiasts, and cold shower enthusiasts, and they've done that for years. Often, the people who do this will offer that the reason they do it is because they just feel better. They get fewer colds, they feel mentally clearer, and they even report some weight loss and better metabolic outcomes.
The findings support that there is an improvement in overall cardiovascular health: blood pressure coming down, sugar coming under better control, and some weight loss. The cold water seems to trigger a shock response that stresses the cardiovascular system and, if you like, elevates heart rate. It almost adds a component of exercise just through the shock of the cold stress. It's, if you like, a little bit of a hack to add on to any exercise regime.
It seems from measurements that ice baths can reduce cholesterol and actually improve the immune system. They've even been shown to potentially reduce auto-inflammation, ease pain, and as many of our sportsmen know, speed recovery. We know that many of our top sportsmen will use ice baths after games, particularly if they have specific injuries. As I mentioned, cold water immersion seems to improve insulin sensitivity and reduce insulin levels, which is pretty good. This is irrespective of whether someone is a regular cold water immersion participant or a relatively new one. So, experienced and inexperienced swimmers, for example, would both get that benefit.
There is a sense of positivity, joyfulness, if you like, for individuals who undertake winter swimming or cold water swimming. This certainly seems to suggest that there may be a response of chemical release within the brain to counter that cold response. The body must do that to help deal with it. So, there are feel-good chemicals released through the process.
Should we all be jumping into cold water? Well, probably not straight away. I think if you were thinking about cold exposure, you'd probably want to just check with your doctor and make sure you didn't have any contraindications. Would you find a frozen-over lake, cut out a hole, and jump straight in? Well, I don't think so. You'd probably want to gradually ease into it. One way you could do that is when you jump in the shower, at the beginning or the end of your shower, you could gradually turn the hot water off and expose yourself to 30 to 60 seconds of cold water. If you did that on your back, per se, that is in fact where your brown fat reserve is located, and that's probably the best place for you to be stimulating that brown fat if you wanted to give that a go.
It's a nice way to ease into it. You could skip a warm-up for regular exercise and jump straight into a cold shower. Interestingly, I saw that wearing cold wet socks can help improve blood and nutrient circulation within the legs, so that's an interesting one. Once you've worked up to it a bit, you could try an ice bath. Athletes certainly do it. It strikes me as a pretty cold thing to do, and the bits that I read would suggest that you don't do it for more than 10 minutes, but honestly, it's hard to imagine how you could keep in there for that long anyway.
Once you feel more competent with that cold exposure, of course, you could then stretch to cold water swimming, but I'll leave that for you to consider. Nonetheless, it's really interesting physiology. It's fascinating to observe that cold exposure can trigger some of these really positive responses, activating the old brown fat, which is metabolically active, improving insulin sensitivity, and improving cardiovascular health.
That cold exposure, by the way, doesn't have to be for that long, and it doesn't have to be water. It may be that cold air exposure, just by being outside on a cold winter's day, could contribute to some of the benefits that we'd see physiologically from this sort of intervention.
Anyway, I'm going to wrap it up there. I think it's a really interesting space. For my own part, I'm going to try finishing my shower today with a bit of cold on my back and go from there. I wish you the very best until next time. I hope you live as well as possible for as long as possible. Take care, and bye for now.
And help people understand their present state of heart health, what their current level of risk is, and the positive steps they can take to improve their risk of heart attack in the future. Go to www.healthyheartnetwork.com.au and click the "Join the Family" button.
