- If you either have or know someone who has type 2 diabetes and you're looking for a non-pharmacologic treatment, exercise may be a great option for you. But what exercise should you do and how much of the exercise should you actually be doing? Well, stick around as we discuss all this and more in this week's podcast. Welcome back everybody to the Building Lifelong Outreach Podcast. Thanks so much for stopping by. For those of you who haven't met me yet, my name is Jordan Wrenke and I'm a dual board certified physician in family and sports medicine. And the goal of this podcast is to keep you active and healthy through life, through actionable, and with informed education. So let's get going today. Today, we're talking all about type 2 diabetes and exercise. So essentially we know diabetes is bad for us, right? It's huge. There's a staggering number of adults worldwide have it. Over 537 million people currently. So 537 million across the world. Projections for 2045 is that over one in 10 adults are gonna be dealing with this. So we step back here, over 12% of people in the entire world will have type 2 diabetes. So it's not going away. So we need to figure out ways to treat it. And it is a huge global health challenge, absolutely. And it's very serious. And even beyond the numbers, it leads to lots of issues. We know we care about this so much because people with type 2 diabetes have a much higher risk of developing cardiovascular disease. Honestly, they're about two or four times higher than those without diabetes. And that's just general numbers we think about. That doesn't include all the other stuff that happens in children that turn to kidney problems, eye problems, all those things that's going on. So lots and lots of issues with type 2 diabetes. So this is a high stakes, and it's really, really important that we treat this. And if we do, hopefully prevent it in the first place, but if we do have it, then to treat it as well. And we have to understand where exercise kind of fits into this. So that's kind of the whole idea here, is figuring out where exercise fits in this treatment paradigm. So there was a major study that we looked at here. Today we're unpacking the findings of a systematic review and meta-analysis back in 2024. The study examined the importance of exercise on hemoglobin A1C and blood sugar control in people with type 2 diabetes. The author was Lang et al. in Collies and published in 2024 in the journal Sports Medicine. And this study is pretty comprehensive, analyzing data from over 85 randomized controlled trials. So 85 randomized controlled trials, that's a big thing. And this represents a massive amount of data. And in this data, there's more than 5,500 participants with type 2 diabetes. We're looking at over 5,000 people, and it provides a pretty solid base of evidence to draw from saying, hey, what we're looking at here is a decent amount of people and over a bunch of different studies. So I think this is a really cool article to look at and I want to share with you. So overall, first things first, the main outcome here we're looking at here is A1C or hemoglobin A1C. And I just want to touch base about what that is first before we move on. This stands for glycosylated hemoglobin, fancy word. The way I kind of explain this is when I explain it to patients is, glycosylation is a fancy term for like sugar getting stuck on something. So this is essentially sugar getting stuck on hemoglobin molecules, which hemoglobin kind of carries our, it's on red blood cells, carries oxygen around. So that's what we're looking at here. It's think of it as a measure of how much sugar you've had in your body for the last two to three months. And two to three months, because typically red blood cells last about two to three months. And so that's kind of where this hemoglobin, glycosylated hemoglobin comes from. And for people with diabetes, keeping A1C within a certain range is really critical. And A1C is directly linked to risk of developing additional complications. So we know that generally when we're looking at cutoffs, we think about like pre-diabetes 5.7, diabetes 6.5, and above that is problematic. Most people with diabetes want to get them under seven. That's like the general, like American Diabetes Association guidelines, for you know, depends on your age, there's various ones there, but generally one of them are seven, the lower, the better. Obviously to not where it's causing you problems or anything like that, but it's a whole other discussion. But long story short, this is really important. This is important because we measure this and this is kind of what we guide treatment based off of. And we know that certain complications, things like heart disease, stroke, nerve damage, kidney problems, even vision loss, all happen when we start to have an elevated hemoglobin A1C over time. And so it's really important in protecting the overall health and wellbeing long-term, but even small changes in A1C can have a noticeable impact on those risks. So for example, every 1% increase in hemoglobin A1C, the risk of cardiovascular diseases goes up by about 13% and the risk of stroke was up about 26%, right? So if you're going up there and you go 2% in a two percentage point increase, then you're gonna have almost a 50% increase risk of stroke, that's pretty big deal. And so that's why managing hemoglobin A1C is a big deal and that's why we care about it so much. And so exercise and A1C, you know, what are the general findings? Well, the main takeaway, exercise is good. It has a positive impact on hemoglobin A1C in people with diabetes. That's like a no-brainer, like I'm not spoiling. That's not a spoiler alert 'cause like everyone knows that, but physical activity is known to be good for just overall health. So why wouldn't it be good for this? But the study kind of solidifies the evidence specifically for diabetes management and moving your body is pretty much always can be a good starting point. That's gonna be my general recommendation. But moving on to the different types of exercise, the question about whether the researchers compare to different types of exercise to see if some were more effective than others, that's kind of the general question they had. And this is where it usually kind of gets interesting, right? So they used a statistical technique called a network meta-analysis. And now a network meta-analysis, it allows for comparing the effect of multiple treatments. So essentially different exercise types, even when they haven't met directly compared head to head. So that's like the whole idea behind this, a network meta-analysis allows us to kind of, yeah, overall just take a big look at comparators that aren't necessarily head to head, right? So we can look at studies that didn't necessarily look at resistance training versus aerobic, but we can look at other studies that did it by proxy. So an analogy that I think is helpful is in trying to figure out who's the best basketball here, right? So even if they've never played against someone, right? We do this all the time comparing stats and I know it's not a perfect one-to-one, but you can still get a good sense of the relative rankings of someone by analyzing their performance against common opponents, right? So if someone hasn't played someone yet in season, but they've played other people, you can kind of figure out generally what's going on. And this is essentially what a network meta-analysis does, in this specific instance looking at exercise. It's saying, "Hey, we're using my proxy, you know, we're compared, how do they compare?" So it's lots of fancy statistical analyses, but that's what it was and that's why it's kind of cool 'cause it's comparing lots of things. And so that's the big thing that we're looking at there. And moving on here, what exercises came on the top really? So based on the analysis, high intensity interval training emerged as the exercise that was most likely to reduce A1C with the highest probability of 97.5%. So what that mean is they say, "Hey, doing this exercise, there was a 97.5% chance that we lower the A1C." And this is a statistical probability though, and not a guarantee for every individual, but it suggests a pretty strong track record. And this study found an average reduction of A1C of about 0.78% with high intensity interval. So you might say 0.78%, what is that? Well, if you think about it, we talked about that change in, right? So a 1% change in A1C leads to a higher risk of stroke. So if we can get it back down to that level, that's better. So 0.78% going from looking at eight to back down almost seven, that's pretty good. The range was about 0.5 to a little over one, indicating a significant potential impact. In second place, we had combined aerobic and resistance training with a probability of just under 75%, meaning more than 75% likely that it's gonna lower it. And it kind of means that programs incorporating both cardio like brisk walking, running, cycling, and strength training, they had a pretty good chance of lowering it. And on average, the reduction of the A1C was about 0.5%. So significantly lower, but still important. And overall, this is gonna be recommendations that I have all the time, right? I'm never gonna say just do one activity. And spoiler, we'll talk to my recommendations later, but we know that resistance training is good. We know that aerobic training is good. So we're gonna, of course, recommend both of those, but maybe we'll tweak it up with some additional hit as well. But those are the big things. And then for those, you know, the other ones they looked at too, they looked at yoga and had a probability of about 56% chance of lowering and reduction of about 0.45%. And then we had continuous aerobic. So things like jogging, swimming at a steady state. The probability was just over 50% with the A1C reduction of about 40.42%. And it's kind of interesting 'cause most people think like, hey, if you're just doing like running, you're just running, going, going, it would lower it more. And the results didn't necessarily show. And that was probably the most surprising thing I thought of this whole study was that just traditional exercise wasn't as good. And they even had tai chi in there, probability of about 45% with a reduction of about 0.38%. And then way at the bottom, resistance training on its own, lifting weights or using resistance band, had the lowest probability among all the exercises showing a benefit chance of about 25%, whereas the A1C reduction was 0.29%. And so it was very interesting to see all they stacked up. For me, these are awesome. This is a cool guide. This is a cool guide. There's a lot of questions though, right? So when I see resistance training is the lowest on the list, I have to think about, okay, what did we actually do for resistance training? Did we just do some gentle, very easy? Did we do like vigorous? And so we'll talk more about that as well. So I'm suspicious of the results that it's that low if you're doing a adequate program that's actually challenging you. But regardless, it is what it is. Those are the results and I'm not here to fight those. I'm just saying that's typically what they've shown here. And so did any go head to head? Were there any direct comparisons? And so while high intensity interval training did come out topping their rankings, the researchers noted that when they directly compared HIIT to combined exercise or yoga or continuous aerobic exercises, it wasn't that, but it wasn't that strong to say for sure that one was superior to the other in terms of the hemoglobin A1C reduction. And so it was kind of almost like a tie at the top, but they did find that HIIT and continuous exercise with combined resistance training were effective at lowering that either way more so than just isolated resistance exercise. But if we step back here, this network of meta-analysis does fancy stuff, right? With the stats and kind of comparing various things here. But when you went head to head, HIIT wasn't like way better than anything there specifically. Once again, looking at combined exercise, yoga, continuous aerobic exercise, like those seem like you can pick one and you're probably good. Whereas it does seem like again, head to head just resistance training wasn't as good as the other ones. And that's another question of why they're doing there. But the overall take was after you pulled out the fancy ones and went head to head, HIIT wasn't like this clear leader necessarily. I thought that was kind of interesting to mention. And let's talk quickly about exercise dosing. The total amount in the dose does seem to matter. And it does mention dose, right? So exercise dose essentially refers to the total amount of exercise you do. And the study found that it's not as simple as, hey, the more you do, the better. There's some more nuance to that. They found a non-linear dose response relationship between the total amount of exercise and the reduction of hemoglobin A1C. And what does that mean? Like that's a lot of words, dose, a nonlinear dose response relationships. So what they mean nonlinear, it's not like straight, right? It's not saying, hey, the more you do, the better you get all the time. They say a nonlinear dose response, meaning the more you do, it probably will get better in terms of lowering A1C, but to a certain extent, it'll kind of teeter off. So if you do go from nothing to doing something, you're gonna have a big improvement. It's gonna be awesome. And eventually when you get to hit a point, it's kind of gonna plateau off, right? Or you might get a little bit improvement, but not nearly as much as it did initially. So that's the big thing. There's kind of a threshold of exercise. So when you're starting to see the most significant benefits, it kind of plateaus off eventually. And once you go beyond that threshold, the additional benefits start to taper off. And it's not that exercise becomes more harmful, but the gains just become less pronounced. And so there's kind of this sweet spot for the biggest bang for your buck. And the researchers estimated that the sweet spot for the kind of essentially the minimum effective dose to get there is around 840 met minutes per week. And you hear met minutes per week, and you're like, what is that? We'll talk more about mets specifically, what that is there in a second. And so what are mets? Here we have a picture of Mr. Met. That is now what we're talking about here, but it's baseball season's just starting right now, and I'm super excited, so I wanna include that, even though I'm a Brewer fan, go Brewer crew forever. But mets, we hear about this all the time in the academic literature. Met, these stand for metabolic equivalent of task. And I honestly, I hate mets. They just don't make sense to anyone 'cause it's just not what anyone uses in real life. But it's a unit that measures the energy expenditure of certain physical activities. So one met is roughly equivalent to just chilling there. You're sitting there at rest, that's what it is. I say existing, so like your existing met is just one. And activities with higher mets, unshockingly, require more energy. And so the higher the met, the more intense exercise is going to be. And here's some examples of different met values. If you're walking at a moderate pace, it's three to four mets. Cycling at a moderate pace, about six to seven mets, running consistently around eight to 10 mets. And to reach that 840 plateau they recommended, you can do various things, right? You can do about four hours of moderate intensity walking, three and a half hours of cycling or yoga, just under three hours of resistance training, or a little over four and a half hours of tai chi. And so lots of different ways to get there. Mets are imperfect, right? 'Cause you're not gonna be running like, I am running at five mets. So we're not gonna know that necessarily. I kind of break it down to that moderate and vigorous exercise based on the physical activity guidelines. But overall, that's what we're talking about for mets. So when you say 840 met minutes, that's what we're talking about there. So that, you know, if you're just doing, walking four hours throughout the week is probably gonna get you there. And that's, I think that's why I wanted to mention that. It's just not very tangible when you hear met minutes. Like, what does that, what does that mean? I just wanted to bring that up. And going beyond that though, as I mentioned before, is more better? The answer is probably yes. The study found that while you might continue to see some additional benefits, they tend to increase very slowly beyond a dose of about 1300 met minutes per week. So as I mentioned before, you're not harming yourself by doing more. And you're just not getting a huge bang for your buck anymore. Once you kind of plateau out at 1300, you say, okay, you're kind of eking out incremental improvements and is your time better used somewhere else? Who knows what. So there's definitely a point it seems of diminishing returns. And yeah, that's kind of overall 1300. So in between the 840 to 1300 is where we probably want to live and kind of want to consider that and look at there. And are there specific optimal doses for specific exercises? Do they find that optimal dose vary depending on the type of exercise? Well, yeah, they did. For resistance training, they kind of found a U-shaped relationship, meaning although it wasn't statistically significant, saying that both very low and very high doses of resistance training might not be as effective as moderate dose for lowering A1C, but they said more researchers needed it. And for me, I read that and I thought, well, what does that mean? Well, low means like you're getting nothing out of it, right? And you're not really doing much of anything. And so no real health benefit. Then you start doing something and you get a big benefit. And then eventually U means like you do a ton and you don't get much benefit out of it. And so I don't quite understand what that means as to like why you do more. The way I kind of read that and interpret this, and this is kind of my general philosophy, is like you just gotta be strong enough. You've gotta do stuff that challenges the main muscle groups of your body, and you're probably gonna get the most bang for your buck. Like will you get a huge benefit from being able to deadlift 600 versus deadlifting 200 or 300? I don't know. I don't know that. I'm not sure. I don't think it's any worse to do that. That's the one thing that this U-shaped relationship was interesting where they're saying very low and high doses may not be as effective. I think the more you do, the probably the better. But the question is if you're doing enormous amounts of resistance training and not doing other things, is it because you're doing so much resistance training in and of itself that you're not doing aerobic activity? That's kind of another thing I thought about is, okay, if you're really high levels of resistance training, you're a power lifter, and you lifted a really heavy load, but then you wait for five minutes before your next rep, maybe you're getting lots of strength, but nothing cardiovascular. And that could also be a reason why we're not having much improvement from that. Just something to think about there. But once again, there's probably a sweet spot where you just do a little bit, and you're probably gonna be fine. But yeah. Otherwise though, for combined exercise, high intensity inner training, continuous aerobic exercise, yoga, tai chi, all that, they generally found a negative nonlinear dose response relationship, which once again means as you increase the dose of the exercise, the reduction A1C tends to decrease to a certain degree, and then it kind of increases at a decreasing rate. So it's that, once again, that idea of diminishing kind of returns. And they provided some estimates based on their analysis for continuous aerobic exercise, around 600 mets per week for significant reduction. Yoga was like 920, so you see up to a lot more. And then combined exercise seemed to require about 950 mets per week. 'Cause continuous aerobic, I've been looking at there, that is gonna be pretty hard, right? Pretty intense going on there. Whereas combined, you might have the resistance, which I'm guessing in these studies, the resistance is just not a whole lot. It's kind of the general theme from here, but that's neither here nor there. But that's generally what we're looking at there. So yeah, there is a dose response relation like we talked about, and kind of have to figure out what's the most important thing for you and how much, how valuable is your time. And so we talked about HIIT before. Is HIIT really like the king? And we talked that it has the highest probability of lowering your A1C, it seems to be most effective in terms of time stuff. And it's good when it works and if you wanna do it. So research estimated that HIIT could achieve significant effects with a much lower dose, right? Of only 320 mets per week. That's why everyone talks about HIIT being so awesome, 'cause you have to do less of it. And that's less than half of what you'd have to do for other types, which is really awesome. And it does seem to pack a punch in a shorter amount of time. And when we talk about HIIT, we talk about high intense activities like sprinting, bigger cycling, that can be up eight mets or even higher. And so to reach, yeah, the 320 mets, it would be potentially even just two sessions of 20 to 15 minutes or three shorter sessions of 15 minutes if you're going really, really hard. But at the end of the day, we say HIIT's king, do HIIT, well, if you have no interest in working that hard, then it doesn't matter if that's what the data says. We can probably get the improvements that we would normally get from HIIT doing other things at more volume and a higher, longer length there. But that's why I don't wanna say HIIT is the exercise you need to do for type 2 diabetes because there's lots of things. Also, we need to figure out, are you healthy enough to do this? If you have type 2 diabetes, you may have other cardiometabolic disease, you may have heart disease, you may have kidney disease, all these things. The question is, are you healthy enough for exercise? I have previous podcasts all about understanding risks for exercise. And you can look at the ePARMedX and kind of ways to evaluate. There's different podcasts all about readiness for exercise. But we have to ask ourselves, are these people who've never done anything, right? Maybe they're very metabolic and healthy, sedentary, don't do anything. Do we just run them right into high intensity training because that's what the quote unquote best thing is based on data? I wouldn't do that. I certainly wouldn't recommend that. Starting exercise, we'd gradually go up and kind of assess risk and see how you're targeting lower exercise and go up there. So that's just one thing we have to think about. Don't automatically be like, "Oh, I heard HIIT, let's go, I'm gonna start sprinting." First of all, hopefully your heart's okay for that. And second of all, your hammy is probably not gonna be here and probably pull a hammy. So as a sports doc, I also care about your orthopedic injuries as well. So not a good idea to go from zero to 100, gradually build it up. And so that's why it's not necessarily the king, but it can be helpful. And were there other factors? They looked at this as well. They looked at in the study, were there any other factors that may influence how well exercise worked? They looked at lots of factors. So they looked at the duration exercise interventions, the proportion of men in the studies, the participants BMI, their age, and even the year of the studies were published and it was quite comprehensive. And interestingly, they found that those factors didn't significantly change the relative effect of exercise on hemoglobin A1c. So pretty much the benefits of exercise seemed pretty consistent across a bunch of different groups, people, time, whatever it is. And yeah, this is hard to generalize this. This wasn't the point of the whole study, but once again, exercise is probably gonna be good for you no matter your age, no matter your body type, no matter what year it is, exercise is gonna be good. And yeah, I'm a shield for exercise. What can I say? And I was like talking about limitations. There's always limitations. Obviously there's always gonna be some and the researchers acknowledged that as well. They rated that their certainty of evidence was very low to moderate, meaning depending on the study, how confident they were in it, they weren't phenomenal. And so there's definitely some room for uncertainty there. And the main reasons for this is that there's definitely some variation in results across different studies analyzed, right? And some of the studies had different methodological limitations. So meaning that they did things differently, so there's limitations there. Now, does it mean we should just like take this as a grain of salt, shouldn't care about it? No, we just have to consider it, right? Every study is gonna have its limitations and that's kind of what we think about. We're putting a lot of studies trying to put it together. Anytime we do that, there's always some limitations. Also stats, right? We do stats that say, hey, we use this fancy statistical analysis to compare this to this, but they've never faced heads off. So that's one thing just inherent to the meta-analysis that we're doing, we're always gonna kind of see and it's never gonna be perfect. So just something that I wanted to mention at least and worth considering. And so final takeaways here, I just wanna talk about my final thoughts. The main exercise, the main point here I'm trying to make is that exercise is good. Not shocking there, right? Exercise is valuable tool for managing type 2 diabetes and improving blood sugar control. Like that is probably the least shocking news you heard today. And the evidence does suggest that high intensity interval training is maybe the quote unquote, most optimal. If you're like, I need to get the most fastest reduction in my A1C, that might be the best. But high intensity interval exercise, combined aerobic and resistance training, yoga and continuous aerobic all have the potential to lower A1C at very similar times. And then just resistance training on its own is probably the lowest down. But the big thing here is really finding what works for you. The optimal type of program, the amount of exercise is gonna vary depending on individual factors. That's the whole point is individualization is so key here. What works best for you might not work for someone else. And overall, yeah, we have to consider a personalized approach for prescription and it might even be worth thinking that, hey, we might have a personalized prescription with the same level that we would for doses of medication, tailoring to the amount and type of the individual needs and their goals. So let's say someone comes in and is like, hey, I've done nothing. And then you start doing 10 minutes a week of something and hey, their A1C went down just a little bit. And then you start titrating up their exercise to improve their A1C, kind of like you would a medication. That's something that's pretty cool and an interesting thing to think about. But yeah, when I see this, I know that there's different responses for different people and I totally expect that. And just like everything, people are gonna respond, some are gonna be great, some are gonna be not great. So we have to just really think about that. And yeah, I thought it was really kind of cool and a cool article to think about how can we lower it? My takeaway is exercise, however it's important to you. And we just titrate as needed and do what we need to do to help you lower your A1C. But yeah, I thought it was a cool study. Hope you enjoyed that, but thank you so much for stopping by. I really appreciate it. If you did like this, it would mean the world to me. If you liked the video on YouTube, subscribe to the podcast on your favorite podcast platform of choice or subscribe to the YouTube channel. Or if you really enjoyed it, sharing with a friend is like the highest compliment you can give. Now, thanks so much for stopping by. Get off your phone and get outside. Have a great rest of your day. We'll see you next time. - Disclaimer, this podcast is for entertainment, education and informational purposes only. The topics discussed should not solely be used to diagnose, treat or prevent any condition. The information presented here was created with an evidence-based approach, but please keep in mind that science is always changing. And at the time of listening to this, there may be some new data that makes this information incomplete or inaccurate. Always seek the advice of your personal physician or qualified healthcare provider for questions regarding any medical condition.
