What's That Rash? - Why wear a continuous glucose monitor?

0:00ABC Listen, podcasts, radio, news, music and more. Australia's alliance with the United States has been the lynchpin of our country's foreign policy for decades. We value the unbroken friendship between the Australian and the American peoples. But between the wars and the tariffs and the unpredictability, are we growing apart? You know who else didn't help us? Australia. Join me, Hamish McDonald. And me, Geraldine Dugas, we ask, So Norman, I've been seeing something popping up mostly at the gym the last couple of months and I wondered if you could shed some light on it. I've been noticing people on the back of their tricep, their upper arm with like a little white button and I'm pretty sure I know what it is but why don't you tell me what it's all about.

0:55So what I see as well, it's kind of everywhere. So that's a continuous glucose monitor, which pierces the skin and measures in what's called the interstitial fluid, your sugar levels, your glucose levels. And it's used for both diabetes, but I think the people in the gym are not using it for diabetes. They're using it to watch their metabolism. And the question is, does it do them any good? Well, Continuous glucose monitoring for people who aren't diabetics is the topic today on What's That Rash? The show where we answer the health questions are simply everyone's asking. So today's question comes from Jane. Jane says, I've been hearing a lot about continuous glucose monitors lately, including from people who don't have diabetes. Do we actually know whether wearing one can tell a healthy person anything useful or are we at risk of just becoming obsessed with every little rise and fall in our blood sugar?

1:50Well Norman if I'm not mistaken this is a conundrum you have been weighing yourself. Yes on the desk in my study at home is a box which says urgent medical delivery which was delivered to my home and it's unopened but in that box is a continuous glucose monitor.

2:14So a very quick story. People might notice that I did a full corners in July on the longevity industry. And as part of that, I've got a whole lot of bloods done. And some of my bloods were just on the high end, particularly in terms of blood sugar control. So not diabetes, but just on the high end. And I was speaking to an endocrinologist. Oh, you should get one of these glucose monitors and check your post-prandial blood sugar. In other words, your blood sugar after you've had a meal and try and keep it down below a certain level.

2:44basically healthy. Everything else was okay. Well, that's okay. Anyway, I haven't opened the box yet. So someone who is in the know told you that it could be good, but they weren't your doctor. Like, they weren't your treating doctor. No, it was a little chat. They just weren't your data. Yeah. And the data goes on to an app and you monitor the app. So I thought, well, I'm basically okay. I'm not sure that I need to have another distraction in my life, and having this thing sticking on the back of my arm, and all the people thinking I'm a wanker. Or diabetic. Well, I don't mind people being diabetic, but wanker is probably worse.

3:22Okay, well, I'm interested to get into Jane's question today and maybe also help you work through some of your thoughts and feelings. Well, okay, because I do think there's a couple of different things going in here. I think first up, if you are managing diabetes, having one of these is completely appropriate. You've talked about that with your doctor. That is what it's designed for. The idea that it's being used by people who don't have diabetes to maybe get some more insights into what's happening in their bodies, that's the thing that's a little bit more of a fuzzy line, I suppose. And so some of it's psychological, some of it's maybe

3:56what we can actually interpret from those data, but we're going to unpack it all. So maybe we start a little bit with these devices because they're actually relatively new inventions. They are and they're very sophisticated for a tiny little device. They're a sophisticated device which then transmits to your mobile phone.

4:14your blood sugars. When you've got diabetes, you can give your clinician access to it as well. And when you go and see your doctor, when you've got diabetes, they can just see what your blood sugar is doing, whether it's going too high and so on adjust your diet. And there's a lot of evidence that keeping your blood sugar and this reason I'm saying this is is the question is whether that kind of discipline translates to people who don't have diabetes. So When you've got diabetes, if you're seeing large fluctuations, it's not good. You want to keep your blood sugar in a reasonable range without risking hypoglycemia. And what were you doing on that day? What sort of food were you having? Is there a pattern of how you're eating and changing that as well as adjusting your insulin accordingly? But we're talking about people who don't have diabetes. And the question is, is there any benefit from monitoring your blood glucose? Why do we care about blood sugar?

5:11What's actually underlying this? Well, blood sugar, we're talking about glucose, which is the basic unit of currency of energy in our body. That's why blood glucose is so important. And it's tightly controlled because when it goes too high, it becomes toxic. And there's all sorts of metabolic effects of consistently high blood sugars.

5:35And what has changed over the last few years is the notion of which level of blood sugar you start to think, well, that's the high end of where risk might start. And the risk that you're thinking about here is the risk of cardiovascular disease. Atherosclerosis, producing, so in other words, the clogging up of your arteries, producing cardiovascular disease, heart disease, strokes, and so on.

6:03When I was training, the limit was up about 6.5. That was where you thought, well, that's the upper limit of normal. Now people are seeing it's round about 5.6 millimoles per liter. So in other words, the range that's considered a healthy range of blood sugars before you get into 5.6. So it's lower than it used to be. So those numbers you're throwing around there, are they fasting blood sugar?

6:24Well it gets confusing but yes they are fasting blood sugar so you've fasted for a certain number of hours and that's when you do your blood sugar but in fact when people have studied this and will come to one study in particular it's everyday levels as well in a range where you don't go too much higher than 5.6. Now everybody will go higher than 5.6 when they have a meal but you don't want that to go much higher than say 11 and then it comes back down into the range. So what I'm hearing is if you don't have diabetes your body's already actually pretty good.

6:53at keeping that into a safe level. So what am I worried about? Why is there a push for fitness interested people to be monitoring this more closely? Well, a lot of this is social influencers. A lot of this is people... No, but what's the kind of theory behind it? Well, it's a very...

7:11It's a very good question because it really doesn't depend on which social influencer you're following. So you're talking about the people at the gym who are wearing them and why they think they might be wearing them versus medical researchers who are looking into continuous glucose monitoring and healthy people to see whether or not it benefits them over the long term. So we'll come to that later. For people who are at the gym, they're concerned about their diet. Are they eating enough?

7:38protein, are they not controlling their carbs because they believe that if they control their carbs that helps them to lose fat and they look more chiseled. Thank you. You get a bit of feedback on your carbohydrate intake and with your blood sugars spiking and you're eating too much in the way of carbs. So that's I think what they think is going on.

8:02Also maybe to do with like energy levels across the day like you hear i'm just thinking about you know common parlance i don't know if there's much to this or not but the idea of like a sugar high or a slump in a non diabetic person that you sort of know that you feel a bit keyed up or extra energetic if you have low glycemic carbs in a heat you sort of get that nice like energy boost and conversely you know that sometimes mid afternoon if you've had that in the morning you feel.

8:27super to super duper tired, is it maybe giving you hints to that as well? It could. A lot of that is largely myth. People have different levels of energy during the day, and yes, you do have a dip in the afternoon. So if you've had a large lunch, you tend to go into a kind of somnolent mode because your parasympathetic nervous system is active to allow yourself to digest the food.

8:49but some people believe it's the angle of the curve going down that actually changes your perception of fatigue and energy rather than your level of sugar. Are you saying that's not true? I hesitate to... Because I think... The dieticians listening have their fingers poised over their keyboards to write us angry emails. Well, and fair enough, but this is a new era... Well, people have been wearing continuous glucose morons for a long time, but not in the numbers who don't have diabetes.

9:17And it may well be that good studies of people wearing continuous glucose monitors shows truly what the effect of blood sugar is if you monitor it with mood and fatigue and so on. We didn't find many reliable studies in that area when we looked at it for this program. When I say we, I'm talking about Shelby, our producer. So that's why I'm hesitating, because in fact, new evidence may come out with continuous glucose monitoring. But there is one study which has looked at this in depth.

9:45where there were three studies really designed to see the impact of changing diet on people in terms of their health and well-being over an extended period of time. And as part of these studies, they wore continuous glucose monitors. So these were ordinary people without diabetes and following them through. And in summary, there was a relationship between what's called time in range, But essentially, it's the time spent, so they got the continuous glucose monitoring, that accurate idea of their blood sugars through the day. And the more people were in the range of around about 3.9 millimoles per litre to 5.6 millimoles per litre, who were in that range, separate from the spikes that they got when they ate a meal, the more they were in that range, the better their cardiovascular health, and they seemed to do better over time. So in other words,

10:43It wasn't the glucose monitor that was doing that, but what the glucose monitor showed was that if the diet that they were on kept them in range, then their long-term prospects of developing atherosclerotic heart disease were lower. Their risks were lower.

10:57Were they using that monitor as a tool? Were the participants able to see those results? Or is it more that they were just put on diets that happened to put them in that range and the scientists were seeing those results? The participants were blind to the results of the continuous glucose monitoring. So it was only the researchers that saw it. So the glucose monitoring did not change their behaviour.

11:17But the implication there was if you could keep within that range on your daily life, then the outcomes were good. So that was the benefit of continuous glucose monitoring is the quality of the data in that study. It's a separate question, which is if you were to wear a continuous glucose monitor and then try to keep within that range, then you would assume that that's a technique for keeping you in a healthy range as you go through life.

11:44But I think what the researchers in this study would suggest is that the diet that they designed for health and blood sugar control would do this without you having to wear a continuous glucose monitor. And it won't surprise you what that diet looked like.

12:00I'm pretty sure I can guess Mediterranean adjacent at least. So what we've got is the idea that keeping within this range is linked to better outcomes. So okay, first tick in that box there. The other question then is about behaviour change and whether it's worth monitoring it. I was thinking about continuous glucose monitors as like a bit of a trend and thinking that maybe it's a bit of an extension to just all of the other health metrics that we're able to access these days thanks to things like smartwatches. Like we're used to being able to know quite granular data about our own bodies in a way that we've never had access to before. You know, your heart rate, but you also know your heart rate variability. You know, how many hours of sleep you got last night? You know, how many hours of REM sleep you got last night? Do you think that this is just something people want because you can measure it so you want to? Well, yes, it's another wearable.

12:55It's just a wearable that pierces your skin. The problem with the behavior that could be induced, and this is what makes people worried about continuous glucose monitors, is that it's another reason to keep on checking your phone and micromanaging the results to probably little benefit. And the real worry is that it changes your eating behavior. So if you are prone to, say, an eating disorder or maybe even compulsive behaviour, and you start to become obsessed with this, it could change the way you eat and your approach to food in an unhealthy way. I know that a couple of the studies that we looked at mentioned psychological distress as a risk and the idea of disordered behaviours as a risk. I do wonder whether when you hear something psychological is a risk.

13:47I know for me, you kind of go, yeah, but like I won't. I'm too smart to get sucked in like that. But maybe everyone thinks that maybe we can't actually deny the fact that when we do start focusing in depth on these sorts of things that we do open ourselves up to those kinds of risks. We do. And you're right to identify a moment ago this notion of the measurable body, the fact that we can measure all sorts of things and that people want to know this about themselves.

14:16and be able to, in a sense, self-help, be able to interrogate their GP about where things are going and adjust their lifestyle and behavior accordingly. And so this is behind the longevity wellness industry, and it's only going to grow. The sort of things that you can measure in the body and collect about yourself beyond the level of knowledge that medical research has been able to deliver. And therefore, it's open to interpretation.

14:43and interpretation that might not lead you in a direction which improves your health and well-being. So this one study from King's College London finds that if you stay within that range, the long-term outcomes are good. Their point would be you just see this diet that we've designed and you're going to stay within that range, you'll be fine. You don't need to have continuous glucose monitor.

15:06Adding a glucose monitor may actually make things worse for you. If you become obsessed, you spend more time on your phone, and you change your diet in an unhealthy way. So kind of just trust that these kinds of diets are, you know, the direction to go in and not kind of sweat it too much. Well, are you... So one of the popular continuous glucose monitors was probably one of the more reliable ones. It's also one of the more expensive ones.

15:32lasts for about 15 days. So maybe if you're on this diet and you're on your exercise program and so on, you wear it for 15 days just to check in. I'm not recommending that, but that might be a sensible way to go that you've got a 15 day period just to check in that it's behaving the way you would expect for the diet that you have been recommended but not wear it every day of the week, every day of the year.

15:56And I mean, it's a medical device. It's not necessarily straightforward to interpret the results either. It probably is quite easy to misinterpret the results. That's true. And there are endocrinologists and other experts who say they know how to look at it if you've got type 1 diabetes. They kind of know how to look at it if you've got type 2 diabetes. The story is a bit more complicated with blood sugar monitoring and type 2 diabetes.

16:21But they've got really no idea how to properly interpret this if people don't have diabetes at all and the chance of over-interpretation and over-reaction will be large and therefore you medicalise somebody or you change things which may not be for the better because you just don't know what to do. So pretty big note of caution coming through.

16:43then Norman here's a little bit of a spoiler for Jane who asked the question. I do want to ask about another group that don't have diabetes that there does seem to be a fair bit of research looking into the usefulness of these monitoring in this group. People with pre-diabetes or people with what used to be called polycystic ovarian syndrome, now it's called polyendocrine metabolic ovarian syndrome, PMOS. Where's the research heading? I think the research is heading that if you take PMOS, There's little question that behaviour change, lifestyle change, can make a big difference to people with PMOS. And therefore, CGMs could be a useful help along the way. And not necessarily, again, wearing it 365 days a year, but from time to time, according to the advice you're getting from your doctor. So there's more and more evidence that there is benefit there. In prediabetes, again, and it's research in Melbourne and elsewhere has shown that you can

17:40Draw yourself back from the brink with pre-diabetes with intense lifestyle interventions. I think the research I think was at the Baker Institute showed that muscle strengthening training can bring you back from pre-diabetes to a much more normal blood sugar level, particularly associated with diet. Now, if you're looking for behavior change, then continuous glucose monitoring can actually add to that and help you along. It's another biofeedback mechanism.

18:09But what you're saying is when it might be appropriate in those smaller groups of people, it's probably still just a short-term tool and that you then kind of move on to just a steady state lifestyle where you're not monitoring this around the clock. Yes, but the evidence is still not in. It may well be you need to wear it all the time so you've got that continuous feedback. It may be that wearing it all the time, you get numb to it and you stop responding to it and therefore intermittent use of this to fix up your behaviour after a few months.

18:38is the right way to go. All these questions need to be answered before you say to people you've got to wear it all the time or it's okay to wear it for 15 days and we'll come back in six months time. We don't know the answers to those questions but we come back to the original question here. It's Jane's question which is should you be wearing them all the time? Why would you do it when you're otherwise healthy? If you know you're eating a healthy diet that's going to be fairly consistent and if your exercise is fairly consistent You're not going to get many surprises in 15 days of use. Well, Jane, I hope that's been helpful to you. Norman, I have to know if it's been helpful to you, what are you going to do with your urgent medical delivery box that's sitting on your table? It's staying in the box for the time being. Oh, really? Yeah, no, it's going to stay in the box. I just I'm looking at my phone too much anyway. I don't need to look at it for my Google's. Fair enough. Well, Jane, thank you so much for the question. We love getting your questions. You can send them to that rash at abc.net.au.

19:35What's in the mailbag? So much in the mailbag, Norman. Lots of people emailing us still about the episode we did a few weeks ago about sleep and your nose and whether different smells can help you have a better night's sleep or not. We talked about the fact that smells aren't great at waking.

19:55us up, as evidenced by the fact that people often don't wake up if there's a fire in their house. Well, Tanya says, listening to your recent podcast on sense and sleep, I was wondering if you'd heard of the wasabi alarm. Well, it's putting your tears in my eyes, just thinking about it. It's designed to wake up people who maybe wouldn't otherwise hear a smoke alarm, such as those who are deaf or hard of hearing. So how does it work?

20:16This one actually experimented with different types of smells, including the smell of rotten eggs to basically figure out what irritates. It irritates the nose. I think that's part of the reason why Wasabi was the one that was the winner was because it actually physically irritates the nose and wakes people up. So puffs out a Wasabi cloud. A Wasabi cloud. If there's a fire. Exactly. Right.

20:39So that one was from Tanya. Laura says, thank you for the episode on smell and sleep. Have you ever heard of onions to help sleep? A friend of mine uses a cut onion to help her preschoolers sleep. She does qualify as child abuse, I mean, really. I'm like, well, you're going to make him cry even more. She says it stops his chronic cough that keeps him awake for hours. If he's had a sleepover at his grandparents and no onion, the cough comes back. What is in the onion that might be soothing his respiratory system? I think this is a topic for another ignoble price here. I think it might be too. I've never heard of this. I thought onions made you cry, not go to sleep.

21:16Alex says, it reminded me of a girl from high school who was committed to using scents as a learning aid. She picked a unique perfume for each of her subjects at the start of the year. Each subject had a matching smell. She sprayed that perfume on herself and the subject.

21:34textbook before each class. And at the end of the year, she wore the matching perfume for each subject exam convinced it would help her recollect the specific knowledge. No idea how much it helped her, but I found it fascinating. Sounds like she was ahead of her years. Yes. We all know that smell can induce memories. You smell stew cooking and it reminds you of your grandma and so on. So there is a relationship between smell and memory already. So this person might have something.

22:03Going fine. Incredible. Well, that is the mail bag. If you want to send us your emails, you can. Our email address is that rash at abc.net.au. See you next week. See you then.