Live Long and Well with Dr. Bobby
Let's explore how you can Live Long and Well with six evidence based pillars: exercise, good sleep, proper nutrition, mind-body activities, exposure to heat/cold, and social relationships. I am a physician scientist, Ironman Triathlete, and have a passion for helping others achieve their best self.
Live Long and Well with Dr. Bobby
#38 Re-thinking Exercise: New Evidence, Smarter Moves
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In this episode, I revisit the most powerful tool for longevity—exercise—and unpack fresh research that changes how we should think about its timing, type, and impact.
We begin with a quick recap of the foundational elements covered in Episode 2, emphasizing that aerobic activity can lower the risk of mortality, heart attack, stroke, cancer, and dementia by 20–30%, even when started later in life.
Then we explore compelling new studies that show how exercise affects everything from blood pressure to brain volume. A meta-analysis of 14,000 participants shows even 15–20 minutes of moderate exercise daily lowers blood pressure. A review of 19 trials links physical activity to better sleep efficiency and reduced wake time. In terms of weight management, a meta-analysis of 116 randomized trials finds that even 30 minutes of exercise weekly leads to measurable weight loss, with a dose-response up to 300 minutes per week.
Exercise also appears to influence mood. A review of 33 observational studies involving nearly 100,000 adults suggests that 5,000–7,000 steps daily correlate with reduced depressive symptoms. While causality remains uncertain, the association is intriguing. Beyond mental health, strength training may reduce inflammation: 19 trials show CRP levels dropped in adults who engaged in resistance training. Perhaps most excitingly, a smaller study found higher cardiorespiratory fitness linked to greater hippocampal volume and better memory in older adults.
To optimize these benefits, we explore emerging science around exercise timing and routine structure. A large study of 14,000 users wearing devices found that intense workouts within two hours of bedtime delayed sleep onset by 36 minutes. Perhaps finish workouts at least four hours before sleep for better rest. Interestingly, data from over 400,000 adults reveals that women gain more longevity benefit from exercise than men—and with less time invested.
We also cover weekend warriors. A UK Biobank study showed no difference in health outcomes based on when exercise occurred, debunking the belief that daily consistency is essential—what matters is that you do it. If you're sleep-deprived, caffeine might restore performance, as shown in a 10K time trial study. Lastly, a novel study using post-workout cold exposure showed that cold immersion reduced blood flow and amino acid uptake for up to 3 hours.
Exercise is the most powerful lever to live long and well. Recent studies show even more benefits for blood pressure, inflammation, sleep and weight loss. New evidence helps us optimize when and how we exercise. How we exercise. Hi, I'm Dr Bobby Du Bois and welcome. To Live Long and Well a podcast where we will talk about what you can do to live as long as possible and with as much energy and vigor that you wish. Together, we will explore what practical and evidence-supported steps you can take. Come join me on this very important journey and I hope that you feel empowered along the way. I'm a physician, ironman, triathlete and have published several hundred scientific studies. I'm honored to be your guide.
Speaker 1:Welcome, dear listeners, to episode number 38, rethinking Exercise New Evidence and Smarter Moves. Exercise new evidence and smarter moves. Well, this is a new type of episode and, as always, I want your feedback, either through comments or taking my questionnaire about the podcast. I will have the link in the show notes. So this episode will begin with a brief, brief review of what we've talked about before, about exercise, and then we will concentrate on what is new. Well, why now? Well, your questionnaire answers and just feedback from listeners. You've requested more information about each of the six pillars the exercise, the sleep, the nutrition, the mind-body harmony, the exposure to heat and cold and social relationships. Now it turns out just about every day I get studies that come across my desk. I get various newsletters, table of contents of journals, and they're really interesting studies and many of these fall into the six pillars, some fall into other topics and I put them into folders on my computer. And now it's time to start bringing those articles back out and packaging them up and sharing them with you. Articles back out and packaging them up and sharing them with you. Well, we are going to talk about exercise and I've alluded to some aspects of my exercise journey, but I thought I'd take a minute or two and tell you a little bit about it.
Speaker 1:When I was in my 20s, while I was going to medical school and I can't say this was the right decision, but this is the decision I made I looked around at people who were 40, 50, 60, and I said, well, a bunch of them look old. What is it? I could do as a 20-year-old, 20-something medical student where I didn't have a lot of time that might keep me from looking old. And so I noticed in older men, their biceps didn't look so good, their abdomen didn't look so good. So I thought, okay, what I need to do in my 20s is focus on those two parts of my body and have worked or thought about that ever since.
Speaker 1:Well, in my late 30s I got the marathon running bug. Everybody was doing them at that time and I decided, okay, if I'm ever going to do it, I better get going before I'm 40. Well, I started with shorter races, worked my way up to marathons. Ultimately, I've done about 14 of them. I qualified and ran the Boston Marathon, which was a high point of my marathon career. Then I turned 50.
Speaker 1:And at the time everybody was doing cycling classes. So this was in the gym. This was long, long before Peloton or things you might do at home. And so I had a bunch of buddies in those classes and they said oh, you know, we're going to go biking outdoors. Would you like to come with us? Of course I had just turned 50,. Time for a nice present for myself bought myself a bicycle.
Speaker 1:Well, now that I was doing running and I'm doing biking, I figured well, it's only one more sport, that's swimming. I'll start doing triathlons. And so I started triathlons and I worked my way up to longer and longer distances and ultimately to the full Ironman distance. Now I've done about not about. I've done four full Ironman triathlons and 13 or 14 half Ironmans and that turns out to be about, for swimming, about 2.2 miles. Then you get on the bike for 112 miles and then you run a full marathon 26.2 miles and that's called the full Ironman. Half Ironman obviously is half that distance. In November I am scheduled to do another Half Ironman here in Texas and I'm trying to do one of these a year. So I'm trying to keep at it.
Speaker 1:Many of you have asked what's my exercise regimen and I'll talk you through that at the end. I have an ask for you, my wonderful listeners Can you share this podcast with other people? If each one of you shared it with one, two or three people, or send it out to your distribution list, to friends or colleagues, that would make a huge difference. Now, as you know, there are no advertisers. I get no financial benefit out of doing the podcast or the articles I write in on my website or the newsletter that goes out. If you're on my newsletter and again, if you want to sign up for any of those, just go to my website, drbobbylivelongandwellcom. But the more people who listen, more people can learn and hopefully I can help more people. So please, please, if you're able to, please share the link.
Speaker 1:Okay, well, as I said, these episodes are going to have two parts to them. First, I'm going to review what we talked about before, and exercise was episode number two, so it goes way back to the beginning, which is about a year ago. I've been doing this now for a bit over a year. As we talked about in that episode, and I've mentioned it many times since then, exercise is the single most powerful longevity lever. If you follow the aerobic guidelines I'll get to those in a moment exercise is associated with a 20 to 30% reduction in your risk of overall mortality, heart attack, stroke, cancer and reductions as well in risk of dementia. And it's never too late. As I talked about in that episode, they did studies in 65-year-old to 85-year-olds and they had substantial benefits. So even if you haven't had a life of exercise, please, please, start now.
Speaker 1:We also talked in that episode about a full exercise program has four components. Yes, we talk a lot about the aerobic part 150 to 300 minutes a week in zone two. 150 to 300 minutes a week in zone two, meaning you're exercising hard enough. So it's not that easy to talk. But second element, strength, once or twice a week, is important. Third, balance and flexibility work is important. And lastly, high intensity or anaerobic work. All right, so that's what we talked about before. Please listen to the episode if you wish.
Speaker 1:Now for the new stuff that crosses my desk almost daily and I'd like to divide these into a couple of categories. Some of these are meta-analyses, meaning somebody went to the literature, said there's 10 studies, 20 studies, 50 studies in people, and they summarized it statistically and that's a pretty good sort of state-of-the-art. What's the summary of the evidence? Tell us. So some of what I'll share is of that meta-analysis type. Others are sort of small studies, new studies, but tantalizing findings. So I can't say we have a definitive answer, but they're very fun and interesting and I want to share them with you. Okay, I'll divide these new studies into two categories, just like with my original episode. First, what are the benefits of exercise? And there's new studies showing new benefits. As always, I will put links in the show notes and if you want to read about them and click on links, just subscribe to my newsletter or read my articles. Both of those, again, are available at my website. Okay, what are some benefits that have come across my desk in new studies?
Speaker 1:First, exercise can help our blood pressure. There's a whole series of studies that we're seeing more and more. Now that people have smartwatches and Fitbits and Oura rings, you can do studies in lots of people very, very quickly and easily. Well, in this study, 14,000 people wore a blood pressure monitor. Now, your normal smartwatch is not going to measure your blood pressure. This was something they added and people wore, and what they found excitingly is that more exercise was associated with a lower blood pressure. I do point out in this study it wasn't just fast walking, it was actual exercise, and what they found is, even with 15 or 20 minutes a day, there were significant changes in blood pressure. Now, these were not massive falls in blood pressure. It was a few points On an individual level that might or might not be enough to get your blood pressure under control, but on a population level, dropping your blood pressure two, three points is enough to reduce population level cardiovascular outcomes by 10 or 20%. So it's a big deal. Will it help you? By all means, give it a go. Do it in the N of one style and let me know what you find All right.
Speaker 1:Second benefit exercise can improve our sleep. So five to 10% of us have insomnia. By all means, listen to my sleep episode and the do's and don'ts, the 12 very practical things you can do to make things better. So what came across my desk? Well, it was a meta-analysis of 19 studies, and what they found is that people who exercised had improvements in objective measures of sleep and subjective measures of sleep, so things like people fall asleep and they wake up an hour, two hours later. That seemed to improve the waking up process and sleep efficiency, meaning, how much of the night were you actually in useful sleep? As I've talked about before, we look for a dose response. So these were observational studies and so it's not the perfect evidence, but when you see more is better and even more is even better, better. That is a clue that maybe it's actually accurate. And they did find that more exercise was associated with even better improvement in sleep. So that's important to know, all right.
Speaker 1:Third, exercise can help with weight loss. Look, we eat, and we probably eat faster and more than we can exercise, but that doesn't mean exercise can't help us. Now this is a huge meta-analysis 116 randomized controlled trials with about 7,000 people, and what they found is even people who exercise just 30 minutes a week lost weight, had some additional weight loss beyond whatever they were doing, and once again we found a dose-response relationship 30 minutes, some weight loss. 60 minutes, 120 minutes, so on and so forth, more weight loss up until about 300 minutes a week, which is about five hours, and for each additional 30 minutes of exercise a week was about additional one pound during the duration of the study, not per week or per month, for the full duration of the study.
Speaker 1:Number four exercise appears to be associated with depression or with a lack of exercise. Here was also a meta-analysis, a summary of 33 observational studies Again not a clinical trial, but a lot of people, about 96,000 adults. What they found is that people who had higher step count during the day, that walked more, that was associated with fewer depressive symptoms. Now, for these people it was about 5,000 to 7,000 steps at least for the benefit to be observed. Okay, let's take a step back here. This is always an issue Is it a chicken or is it an egg problem? Just because we observe the relationship, it may not be that walking more reduces depression. It could be the other way around, that as people feel down and sad and depressed, they may not feel like going for a walk as often. So this is one of these findings which you could look at as oh I better get my steps in, it'll help my mood. Or maybe it's the other way around Not that the walking's going to hurt us. Of course, it's wonderful for us, but just take this with a little bit of grain of salt. All of these studies, or many of the studies I've just mentioned, you're going to see more and more of them, because so many people are wearing smartwatches and Fitbits and that data is automatically at times uploaded to the cloud and then researchers might be able to work with the data. So we're likely to see more and more studies like this.
Speaker 1:Here's an exciting one Strength training. Now, this isn't aerobic training, this is strength training. Lifting weights Seems to reduce markers of inflammation, and I'll do a study in an episode on inflammation. But inflammation's been associated with all sorts of diseases obvious ones like ulcerative colitis and others, but as well with heart attacks and cancer. And what this article was about was 19 clinical trials. So these were actually studies where people either did strength training or didn't. Folks were in their 60s or above and what they found is one of the key markers blood markers of inflammation that's often measured CRP or C-reactive protein, fell when people did resistance training. Now, these studies didn't tell us that the diseases associated with inflammation went away or were reduced in risk, but the measure of inflammation in the blood went down with exercise and maybe that will be associated with less disease or less severe disease. This article wasn't able to tell us that. And the last benefit, one I'm very excited about many of you, as you get older, will as well.
Speaker 1:Exercise may affect brain volume. So the hippocampus is a region of the brain and it's associated with memory and it tends to deteriorate, tends to shrink, as we get older. Now, it shrinks whether we have dementia or we don't have dementia as we get older, so it does seem to be related to aging and maybe to loss of memory. Now, this wasn't a huge study, but it had 165 people and they found that folks that had higher fitness levels, their hippocampus was bigger and if they had higher fitness levels, their memory, their spatial memory, was better. Now, every study has flaws. This one on brain has flaws, and all the other ones I just talked to you about on brain has flaws and all the other ones I just talked to you about. But when you step back and look at all of the articles, all of the studies, like in a court of law, there's what's called the preponderance of evidence, not beyond a reasonable doubt, but the preponderance of evidence. So for me, the preponderance of evidence, even though many studies are flawed, suggest that exercise has lots of benefits.
Speaker 1:Okay, maybe you're convinced Either continue the exercise you're doing or maybe you're going to do even more exercise, and I hope you are convinced. I would love that to be the case because I really really do believe it is our strongest lever to live long, meaning more years, but to live well, good years, preview of coming attractions. I'm going to record my next episode about how many good years do we have left, meaning whatever age we are. Are we going to live a lot longer, just a little bit longer? Are we going to be very functional or are we not? And can we predict that? Because that obviously could affect our life and how we think about our life and how we spend money and save money and everything else. And yeah, no more on that right now. Okay, so if you're convinced exercise is good, then of course you want to maximize the benefit of that actual exercise and make a really good protocol for you. All right, so here's some studies. Again, these are not necessarily the answer, but they're intriguing and you can try many of them out yourself and see if they work for you. Listen to my episode on N of 1 studies if you want to get some more detail on how to do it. Here's one Don't exercise too late in the day.
Speaker 1:That was the finding of a recent study that was published. Now we know, and I've just talked about it, that sleep helps insomnia. I mean, excuse me, exercise helps insomnia. So if we have problems with sleeping, getting exercise is a good thing. But exercise revs our body up, it increases our sympathetic fight or flight activity and it also wakes us up. Now, when it's time to sleep, we kind of want the opposite. We want to calm our mind, we want to calm our body, which is the parasympathetic nervous system part of our body. Okay, so that's the background.
Speaker 1:Here's a study. They asked the question does it matter what type of time of day that we exercise related to our sleep? There were about 14,000 people average age in their late 30s, and they looked at data on folks wearing various devices like the Fitbits and smartwatches and they looked at it for about a year and they looked at when people normally went to bed and went to sleep and how long they typically slept. Then they asked the question, since they know when they exercise because they had on a Fitbit or whatever else, they knew when they exercised and they knew when they went to bed. So they then asked the question did the time of day or night that they exercised affect when they went to bed? On average, these folks exercised about once every three days, so a couple times a week. So you know, not an unreasonable group of folks to look at.
Speaker 1:What they found reassuringly is that if you exercise at least six hours before bed so if you go to bed at 10 pm and you've exercised before four in the afternoon there was no negative impact on sleep. Okay, so that's good. But if you exercise less than two hours before going to sleep the usual sleep time those people went to sleep 36 or fell asleep 36 minutes later and it seemed to affect sleep quality. So that's within two hours. Well, there was also an impact when it was two affect sleep quality. So that's within two hours. Well, there was also an impact when it was two to four hours. Again, if it's 10 o'clock is your bedtime. If you exercise from 6 pm on, it might have some impact. They also found a dose response and you know I love to find dose responses. What does that mean? The closer to bedtime, the more the impact. The more intense the exercise, the more impact on sleep. It didn't seem to happen if you just went for a gentle walk.
Speaker 1:They were looking at folks who actually exercise, who actually exercise. Okay, so let's ask our chicken and egg question Is it that the exercise close to bed woke us up, got our sympathetic system working in overdrive and therefore couldn't fall asleep? Or is it the opposite, just that people got home late, they didn't get around to exercising till late and therefore everything else got backed up and they went to bed later. So it had nothing? One could argue it has nothing to do with the fact that they had a sympathetic thing going on in their nervous system, but it may just have been a simple time thing. I kind of think that it's real. Why? Because that same type of intense sympathetic response happens after cold plunge and wakes people up, myself included, and I can't do a cold plunge before bed because I'll never be able to fall asleep. So I actually think it's real. But for you, do an N of 1 trial. Do your exercise, do your intense exercise, but perhaps finish at least four to six hours before you want to sleep.
Speaker 1:Okay, next article. This was fascinating. It was tantalizing. It was in the press and a fascinating article all around For my women in my life. I'm thrilled by the results of this study. For the men in our lives, me included not as good news for us All. Right, so what did we learn? Well, we know, in general, exercise is good for all of us. It has so many benefits. But in this study they asked the question do women benefit more than men in doing exercise? So we all do exercise. Do women get more benefit than men in doing exercise? So we all do exercise. Do women get more benefit than men?
Speaker 1:This was a study of 400,000 adults across a range of ages 27 to 61. They followed these people for 20 years and what they found again was exercise folks, that exercise that was associated with a lower rate of death, and for women, that was a 24% reduction. That's fantastic. For men there was a reduction, but that was only 15%. So women got almost 50% more benefit in the database. 50% more benefit in the database. Now for everyone. Exercise lowered the risk of heart attack or stroke. But again, women got 36% benefit, men 14%. Now even more tantalizing that women got benefits with less exercise, that those benefits were evident with 57 minutes of exercise per week versus men 100 minutes. So not only did women seem to have more benefit, they seemed to get that benefit with less minutes exercising. Now there's a lot of theories as to why that might be the case. Men have more muscle mass, more mass in general, so maybe it takes more for the male body to get the benefits. Who knows? It's an observational study. It's fascinating, it's tantalizing, and if you're a woman who isn't exercising a lot, now's even more reason to do so. But the study showed that only a third of the people in the study actually met the guidelines for typical exercise, the 150 to 300 minutes. So we can all benefit and perhaps women will benefit more.
Speaker 1:Okay, next fascinating thing about how to exercise. You might have heard about weekend warriors. So weekend warriors are folks that don't exercise during the week, but they get all their exercise on the weekend, they have more time, they have less stress, and Saturdays and Sundays, that's when they play pickleball, that's when they get to the gym, that's when they go for a run, but Monday through Friday not so much. And so this was a study of 89,000 people in the UK biobank. Again, this is an observational study, it isn't a randomized trial, and folks wore an accelerometer like a Fitbit or a smartwatch and they wore it for about a week and they tested things. And this is a study that often I don't like because they measured a zillion things and, as you know, when you measure a zillion things in a database, you're likely to come up with something positive.
Speaker 1:But they did this in an interesting way. They looked at several hundred diseases and they compared people who exercised with people who didn't exercise, and compared the weekend warrior type of exercises versus those that exercise all week long, and they looked at things like hypertension, diabetes, obesity and a bunch of other things. In these several hundred different diseases. There was no difference the exercise was beneficial, whether it was all during the weekend, as a weekend warrior, or whether it was spaced out. So doing the exercise when you can is all that matters. So what's the tip here Get the exercise when you can.
Speaker 1:We've talked before about should I skip sleep to get to the gym. No, you can't make up your sleep, but you certainly can make up your exercise, and you could do it on the weekend. So that's wonderful, okay, but what if you don't sleep? Well, there was an interesting study that compared folks. These were healthy runners, and they made them do a 10 kilometer time trial, meaning they put them on a treadmill and had them go as fast as possible or maybe it was an outdoor time trial, I'm not exactly sure 6.2 miles, and they measured how long did it take to complete that distance? And then they compared them when they had a normal amount of sleep, like eight hours, versus a restricted sleep where they only gave them three hours. Not surprisingly, when they only had three hours to run, that distance took longer. Instead of 49 minutes to do it, on average, it was 52 minutes, so about 5% longer. What they then examined is well, what if we gave them caffeine? Well, it reversed the effect of less sleep. Now, I'm not suggesting that you don't sleep and then you take caffeine for it, but what they found is that, even if lack of sleep hurts you the next day. In terms of exercise performance, caffeine appeared to reduce it in this small but again tantalizing study.
Speaker 1:Well, I want to finish off with one last study, and this is interesting. There's been a lot written about cold plunges and strength exercise. You know, should you do a cold plunge after you do a strength workout, will it affect how your muscles repair and get bigger and stronger? Well, I don't know that. I want to definitively answer the question with that, but they really did an interesting study. They took 12 men and they had them do a resistance strength exercise workout. Then they put one leg in cold water and one leg in normal water and what did they find? They looked at their blood flow in the two legs. Not surprisingly, the blood flow was reduced in the cold leg. You know cold leg. There's contraction, vasoconstriction, the blood vessels get smaller and the blood flow microvascular blood flow is lower. That's not a surprise to me. Flow was lower. That's not a surprise to me. What was a surprise is that lowered vascular change, lower blood flow was reduced for up to three hours. And they also found that amino acids, which build protein, there was less uptake in the muscles.
Speaker 1:I've talked in my prior episode about exposure to heat and cold, and I mentioned how the cold plunge, which might only be three minutes, the impact goes on for hours and hours in terms of how you feel. Here's another study that suggests that the benefits or the changes or whatever, goes on for hours. So I found that very interesting. As I mentioned at the outset, I wanted to share with you what my regimen is for exercise. Might be interesting for you.
Speaker 1:I do about three races a year. I do a shorter distance, triathlon, called an Olympic distance. I do a swim run raceathlon called an Olympic distance. I do a swim run race every year with my brother. It's a fun thing where you do a series of run, then swim, then run, then swim, and you're generally going from island to island. So you run across an island, jump in the water, swim to the next island, get out, run across that island, jump in the water and do that again. So that's something I train for once a year. And then I do an Ironman distance or this year it'll be a half Ironman distance once a year.
Speaker 1:So how do I get ready? And it varies during the time of year and whether it's a shorter race I'm getting ready for or not, but in general, I try to swim one day a week. I do a long bike and followed by a run, so you get off the bike immediately run. Sometimes the year that's about a two and a half hour session, sometimes it's more like three or four hours. Again, it depends upon what I'm doing that time of year. I try to do an indoor bike once a week. I do a strength session, as I've talked about. I have a trainer that comes once a week because I won't do it by myself, and then I try to do a speed run on the treadmill, short intervals, once a week. So that's about typically five or six hours of exercise a week. It can be more, it can be less. All right, let's wrap up.
Speaker 1:Exercise has so many benefits. Please do it. Do it when you can during the week. As we learned, the weekend warrior does fine. You can do it in short bursts. It doesn't have to be an hour at a time. You can do five or ten minutes if that's all you have at that moment. It is the single best way to live long and to live well, and I want both of those characteristics for you. And if you have a chance, please share the podcast with others. Until next time, take care, have some fun exercising and then, of course, live long and well. Thanks so much for listening to Live Long and Well with Dr Bobby. If you liked this episode, please provide a review on Apple or Spotify or wherever you listen. If you want to continue this journey or want to receive my newsletter on practical and scientific ways to improve your health and longevity, please visit me at drbobblivelongandwellcom. That's doctor, as in D-R Bobby. Live long and wellcom. That's Dr, as in D-R Bobby. Live long and wellcom.