Studies point to exercise as possible way to help prevent dementia
Host Amber Smith: Upstate Medical University in Syracuse New York invites you to be "The Informed Patient" with the podcast that features experts from Central New York's only academic medical center. I'm your host, Amber Smith. Several research studies have shown that vigorous exercise, walking, even household chores, can have positive effects on the brain. Can this reduce our risk of developing dementia as we age? I'm talking about this with Upstate exercise physiologist, Carol Sames. Welcome back to The Informed Patient, Dr. Sames.
Carol Sames, PhD: Thank you so much, Amber. Glad to be here.
Host Amber Smith: We've talked before about the benefits of exercise, not only to the whole body, but specifically to the brain. But now I understand there are three major long-term studies involving hundreds of thousands of people over the course of years, that get fairly specific about the types of exercise, the intensity, duration, that provide protection against dementia. Can you tell us about them?
Carol Sames, PhD: Absolutely. So the first study is coming out of the U.K. and they had about 500,000 individuals. And what they did was they recruited them between like 2006, 2010, and they started following them one year after recruitment and then followed them until the end of 2019. So, you're looking at between eight and 12 years. And basically what they did initially is they collected information about their activity. They used questionnaires, what type of activity, what type of more vigorous activities, so more sports type activities - hiking, running, biking, more vigorous types of activities. But they also included household activities, job-related activities, if anybody was using biking or walking to work, or were they doing any type of transportation for others.
They also collected some what we call mental activity, so looking at social contacts, uses of electronic devices. They also wanted to look at educational levels. And what made this study kind of unique is that they had data, blood data, and they were able to look at some genetic markers of dementia. And, they also asked about family history, since we know that there are certain types of dementia that do have a genetic component. And so what they found out was that individuals who had been engaged in the more vigorous type of physical activity reduced their risk of all-cause dementia, Alzheimer's, dementia, and vascular dementia by 35% compared to the lowest level of physical activity. But then they also found that people that were engaged in household activity reduced their risk by 21%. And generally household is more of a moderate level of exercise intensity. So it doesn't have to be things that are highly vigorous.
Host Amber Smith: So vacuuming, dusting, those sorts of just movement?
Carol Sames, PhD: Exactly. Mowing the lawn, probably all the things that we don't necessarily enjoy doing. But the point is, the body is moving. They are physical activity. They don't require us to become out of breath and to be sweating profusely. And so I think that's a big, really important finding in this study because I think many people, when they think of physical activity, they think it has to be something that is arduous. And then, how many people want to do arduous activity?
Host Amber Smith: That was a study out of the United Kingdom, correct?
Carol Sames, PhD: Yes. Mm-hmm.
Host Amber Smith: So what else has been found since then?
Carol Sames, PhD: So another study, also that just got published in August (2022) was what we call a systematic review and a meta-analysis. And so what they did was they took 38 articles, and when you add articles together like that, you really increase your sample size. And, so what they had was 2 million people that were in these 38 studies. They followed them for three years. And these individuals started without dementia, and then they followed them for three years to see, like, a combination of all of these studies. They also looked at leisure activities, things that spanned from what we would call more vigorous to less vigorous activity. They also looked at cognitive outcomes, things like reading books, magazines, newspapers, watching television, writing, playing cards or checkers or board games. And then they also include listening to music or painting. And then they also include what they called social activities. So, you know, being around friends or family or volunteering or being in any type of social club. and so the results were that when you controlled for age, education, and gender, this huge variety of physical activity had a 17% lower risk of developing dementia than those that were inactive. So again, we're getting these results from large sample sizes following people, looking at the individuals who develop dementia and finding out that they tend to have higher physical activity levels. And in the example that I just gave in the meta-analysis, they also had more social activity. But here's the conundrum. People that have more social activity tend to be engaged more in cognitive activities and physical activities. So, you know, that's a little tough to tease out.
Host Amber Smith: Well, when we talk about a risk reduction of 17% or 21%, or even, I think you said 33% on the high end, those sound like small numbers, but the, those are really huge differences, right?
Carol Sames, PhD: They really are. Because think about, this is the sample size we're looking at. So we're not talking about looking at 20 people, right? You're talking at looking at 500,000 in the first study, 2 million in the second study. That's an impressive risk reduction, understanding that when we talk about the human body, there's not one factor that impacts an outcome. There's multiple risk factors. So, clearly I think the research is demonstrating that physical activity is a strong risk factor reducer, and there's other, also, components to that beyond physical activity or cognitive activity or social activity.
Host Amber Smith: Now, a third study published in August 2022 in the Journal of Science and Medicine in Sport focused on children. Can you tell us about that?
Carol Sames, PhD: Super unique study. So they had children that were between the ages of seven and 15 years old in 1985. And it just so happens they were participating in a study, and they collected data on their cardiovascular fitness, their muscle strength, their muscle power, and then their waist to hip ratio. And then they followed up from 2017 to 2019 these same children, which were clearly now middle adults, they were now 39 to 50 years old, and they wanted to see, were there any differences?
Not surprising, the adults when they were children, if they had higher levels of fitness strength and lower waist hip ratios, they had a reduced risk of developing dementia than the adults who, when they were children, had poor fitness, poor strength, and greater waist to hip ratios.
Host Amber Smith: So someone who as a child was not very active, or wasn't very active their whole life, is it too late to get benefit from becoming active?
Carol Sames, PhD: No, it's not. A study that came out of the Cooper Institute in 2013 actually looked at midlife, so around the age of 50. They looked at cardiorespiratory fitness. Then they followed people until either they died or they developed dementia. And what they found is that they divided fitness levels into five different levels. The individuals that had the highest level and the second highest level had a significant lower risk for developing all cause dementia. So that's midlife impacting later life. Again, really highlighting the impact we get from being active.
Host Amber Smith: This is Upstate's "The Informed Patient" podcast with your host, Amber Smith. My guest is Dr. Carol Sames. She's an exercise physiologist at Upstate, and we're talking about how physical activity can protect people from the development of dementia.
So let's get a bit more firm definition of what counts as vigorous exercise. Is this another word for aerobic?
Carol Sames, PhD: So when we talk about aerobic or cardiovascular activity, we have a continuum of intensity. So we can have intensity that's moderate. Moderate level intensity is being able to carry on a conversation. So if I go out and walk with my friend, you know at a nice easy pace, doing some household activity, generally that's moderate. Intensity, vigorous intensity is those activities where you notice an increase in your breathing. You're really not carrying on a conversation, maybe saying yes or no. You'll really notice that your heart is elevated. You can tell you're doing something that is definitely more challenging than a moderate type of intensity.
But here's what we know, in terms of the guidelines, the guidelines for aerobic or cardiovascular activity is 150 minutes a week of moderate intensity activity, or 75 minutes a week of what we call more vigorous activity. Or a combination of both. So, if you think about 150 minutes -- and that's the goal; people might not start there. People might start with 10 minutes in a week, and that's fine because the new guidelines are emphasizing the importance of reducing sedentary behavior, so that even if I get my 150 minutes of moderate activity in, in a week, but I sit for long portions of the day, I actually negate some of the benefits that you get from cardiovascular activity. So we want to move more, sit less, and aim for that 150 or 75 minutes a week of either moderate or vigorous activity.
Host Amber Smith: And of course the 150 minutes isn't done in one session. You spread that out, so 10 or 20 or whatever minutes, 30 minutes a day, something, right?
Carol Sames, PhD: Absolutely. And for people that maybe they haven't been very active, right? They maybe have a sedentary job. You're just starting with a few minutes. Maybe what I do is, I walk a few minutes every hour, and those minutes add up. They don't have to be done in a chunk. So again, the research is really suggesting the power of movement. So maybe I walk for five minutes here, five minutes there, and the next thing you know, I've walked for 15 minutes. And I build off of that because that 15 minutes is so much better than no minutes at all.
I also have to say that the guidelines for adults and older adults are strength training and we are definitely highlighting the importance of strength training. In fact, for older adults, strength training and what we call power training is even more important. So why is strength important for adults and older adults? Well, simply put, you need muscle to move. And if you don't have muscle, you're not moving, you're not going to complete that cardiovascular activity. We need muscle functionally, just to do all the functional things that we need to exist in our world, whether it be going up and down stairs, whether it be making a bed, doing a wash, just all of those activities. We need strength.
As we get older, what happens is that we start to lose what we call our fast twitch muscle fibers. They're our power fibers. And a lot of times people say, "well, who cares? Older adults don't need power. That's more of a younger adult or athletic population," to which we say, "absolutely not. You need power to get outta your chair. You need power to take the first step. If you have stairs, that's all about power." We need power as we get older. And so power training with older adults, sometimes that's our first line. We won't even start cardiovascular activity if people are really weak. We'll start with strength training and power training first.
Host Amber Smith: So these recommendations for physical activity, if we also want to keep our brains healthy, are the exercises for our brain health on top of the physical recommendations, or do we get the benefit of the brain health while we're working out to keep our bodies healthy?
Carol Sames, PhD: Well, certainly there probably is some carryover there, right? That it's difficult to tease those out. But the research is still suggesting that we need to be engaged cognitively. And that is just such a wide spectrum of activities. You know how people say I don't really like to read? And it's like, fine, you don't need to read to be engaged. Do you enjoy listening to music? Do you enjoy looking at art? I don't do crossword puzzles because I'm terrible at them, but do you enjoy something along the lines of that? There's some question about television. So the research is suggesting it's not just like television to be on in the background, but that I am engaged with whatever is on the TV, so that there's an actual engagement. Carrying on a conversation, that is cognitive. There's all different levels of cognition that you choose from, just like with activity. There's not one best physical activity, and there's not one best cognitive activity.
Host Amber Smith: Can physical activity be cognitively protective for people with a family history of dementia who may be at high risk themselves? Or the studies that we just spoke about, were they more meant to apply to people of average risk?
Carol Sames, PhD: No. So here's what's impressive is that even in individuals that have a family history, being active is reducing the risk. So I mean, again, that is really powerful, when we talk about the impact of being active. Certainly, as I usually tell my students, you can't choose your parents, right? We don't know how to do that yet. So, I'm born with these genetics, and so what can I do? So I have a mother who has very severe dementia, and hopefully my lifetime of activity, and my lifetime of enjoyment of reading can help to reduce my risk. It doesn't mean it's going to be eliminated. Genetics is genetics, but we know study after study when you control for family history, or in the example of that U.K. article, they actually controlled for the biomarkers and the family history. There still was protection with physical activity.
Host Amber Smith: Gosh, it sounds like if you are at higher risk, maybe that's all the more reason to make sure that you get the activity.
Carol Sames, PhD: And also, it's like when people say I want to lose weight; that's why I want to be active. Remember, you're getting a plethora of other benefits of being active. So we're just talking about dementia here. There are all the other benefits that come with being active, you know, just reduction in cardiovascular disease risk, being able to maintain appropriate weight, reduce weight gain, having better muscle quality. So what happens as we get older, we start to see more fat infiltrate muscle, and so our muscle quality goes down. So the whole reduce the risk of depression and anxiety, bone health, I mean the list goes on, and on, and on, seven different types of cancers. So you're getting all of those benefits whether you want them or not. You're active, you get all the benefits.
Host Amber Smith: Well, Dr. Sames, I appreciate you making time for this interview.
My guest has been Dr. Carol Sames. She's an exercise physiologist at Upstate. "The Informed Patient" is a podcast covering health, science, and medicine, brought to you by Upstate Medical University in Syracuse, New York, and produced by Jim Howe. Find our archive of previous episodes at Upstate.edu/Informed. This is your host, Amber Smith, thanking you for listening.