We know that exercise could lower your dementia risk by up to 90 percent, but could meditation have a similar impact on the brain? Harvard neuroscientist Sara Lazar found that compared to a control group, 50-year-olds who meditated for at least seven to nine years not only had more gray matter in parts of their brain, but the same amount in their frontal cortexes—the part of the brain that’s responsible for memory and decision-making—as adults half their age. Since then, Lazar has continued to focus on how meditation could transform the brain and whether it could even help prevent additional memory loss in adults living with MCI or early-stage Alzheimer’s.
- In another study, Lazar found that participants who had never meditated before and signed up for an eight-week mindfulness course had increased thickness in their hippocampus—responsible for memory—and a section of the brain known as the “pons,” where neurotransmitters are created
- The participants’ amygdalas, responsible for anxiety and aggression, also shrunk
- Currently, Lazar is recruiting participants to study the impact of meditation on dementia-related symptoms in adults with MCI
Being Patient spoke to Lazar about how meditation could improve brain health, reshape our brains or even reverse symptoms of cognitive decline.
Being Patient: Let’s start with one of the first studies you conducted. Tell us a little bit about what you found. What did meditation do to improve our brain health?
Sara Lazar: The very first study we did involved looking at long-term meditators and comparing them to controls. We found that there were several brain regions where there’s more gray matter in the long-term meditators compared to the controls. And that is the first evidence that meditation could actually change your brain, which was pretty novel at the time. We followed up that study by looking at people going through an eight-week meditation-based stress reduction program. What we found is that even after eight weeks, we can start to see changes in brain structure and function. And so that was really novel at the time, demonstrating that even a short period could have real impacts on people.
Being Patient: When you say that meditation actually added gray matter to brain regions, what exactly does that mean—that we’re adding brain cells?
Sara Lazar: We know that only in one part of the brain, called the hippocampus, you can actually get new neurons. Neurons look a little bit like trees, and although we’re born with all the neurons that we’re going to have, we can greatly change the number of branches, and the number of roots, and where those branches and roots are rooted in the brain. So we weren’t able to look at this, but in animal studies, when you get these similar sorts of changes in brain structure, they can go in and chop up the brains of the animals and show that you can get greatly dramatic changes in the number of branches, and number of roots, or the direction they’re going in. We think that’s what’s happening here.
Being Patient: You mentioned the hippocampus, or the area of the brain that’s responsible for memory, and in people with Alzheimer’s, the hippocampus is what usually goes first in terms of brain degeneration. How could meditation impact the hippocampus?
Sara Lazar: The hippocampus was one of the main regions we found in the eight-week study and also the posterior cingulate cortex. Both of those regions are the ones that are most strongly impacted in Alzheimer’s disease. Both of them get smaller with Alzheimer’s and got bigger with meditation.
Being Patient: When we meditate, what is happening inside our brain to make it stronger? We’re told that for optimal brain health, we need to change patterns of thinking and do things that are outside our comfort zone. That’s all related to neuroplasticity, the brain’s ability to rearrange synaptic connections after learning something new, right?
Sara Lazar: Exactly.
Being Patient: What are we doing to our brains when we meditate?
Sara Lazar: We have many of the puzzle pieces and there’s still a few pieces missing, but what it’s looking like is that when we meditate, certain parts of our brain, including the hippocampus and the posterior cingulate cortex, become less active. They become more quiet, and the posterior senior cortex is the main region associated with mind wandering. Again, it’s the area that’s destroyed by Alzheimer’s disease, and as it gets destroyed, we have more mind wandering. And then as it gets thicker, it’s becoming less active. There’s a phrase in neuroscience called “neurons that fire together wire together,” and this is the job of the hippocampus. As you’re meditating, it’s sort of like physical exercise. As you activate a certain region, there’s going to be more branches and roots in that area, so it’s going to attract more branches and roots, and those are going to get strengthened over time. Just like the more you work out your arm muscles, the more you work a brain area, the bigger it’s going to get, the more complex the connections are going to become, and it’s going to get bigger.
Being Patient: When we meditate, are we taking our brain waves on different levels, like alpha, delta, etc.? Is that what’s also strengthening them?
Sara Lazar: Yes, exactly. Again, there’s not a lot known. There’s different types of neurons and different types of neural activity within the brain. Also, the brain is composed of layers. So the different types of activities have to do with the different layers, and the different layers have to do with the information coming in, or coming out, or where in the brain they’re talking to, this sort of thing. So yeah, all of that’s definitely happening, and it’s sort of different pieces of the puzzle. We have a little bit of the alpha, beta, gamma, delta information, we have a little bit of the brain activity, and we have a little bit of brain structure, and they’re all telling us different bits of information.
Being Patient: Is there a simplistic way to explain it, like going from alpha to gamma or to delta?
Sara Lazar: It’s been a bit of a mess. There have been so many studies and they’ve all found different things, because there’s not one unique form of meditation. There’s lot of different ways of meditating, and also it’s really clear to anyone who’s ever practiced that when you first start out, you practice a little bit differently, and then as you get more experience, it shifts a bit, and you practice a little bit differently, and then you practice more, and it shifts a little bit. Each of those adaptations is going to change brain activity in different ways. So it could be that for beginners, it’s about alpha and beta, but then as long-term meditators, it gets more into gamma. It depends on what type of meditation they’re doing. There’s a lot of different factors.
Being Patient: What type of meditation did you study? What was the cohort practicing?
Sara Lazar: For the pre- and post-study, we’re looking at mindfulness-based stress reduction. Mindfulness is derived from Buddhist meditation, but it’s very secular, so there’s no Buddhist philosophy included and it’s pretty much divorced from all the religious connotations. It’s just being aware of breath and body sensations and the present moment in this nonjudgmental way. That’s actually the big question: to what extent does Eastern philosophy influence brain activity? And it could, but we just don’t know. The general idea is that the short clinical ones are a very secular form of meditation.
Being Patient: How often did people have to meditate for you to see an impact on their brains?
Sara Lazar: In our study, people practiced on average for 30 minutes a day, but because we asked people to it write down, we know that some people practice more because they’re told to practice for 40 minutes a day. So we know some people actually practice for 40 minutes a day, every day. Some people practice 40 minutes a day a couple of times a week. Some people practice just five or 10 minutes a day, occasionally. Some people practiced all over the place, and so it was on average, 30 minutes a day. We haven’t done experiments to know exactly how much you need to practice. There have been other people doing studies though showing that even a week or two of practice causes changes in brain structure and function. In certain terms of behavioral metrics, like symptom reduction, we definitely know that even five or 10 minutes a day can be really powerful.
Being Patient: That’s not much. You really have to work up to 40 minutes, but five or 10 minutes a day is pretty doable for most people, right?
Sara Lazar: Yeah, and it’s clear. Again, it’s sort of like physical exercise; the more you practice, the more you’re going to benefit, but even five or 10 minutes a day can really, in terms of just taking the edge off with stress and helping people calm down, it’s really good.
Being Patient: We’ve interviewed neuroscientists studying the role of exercise and it turns out that we probably know the most about aerobic exercise and its impact on the brain. So 20–30 minutes a day of aerobic exercise actually helps your hippocampus. It’s interesting that meditation can do the same thing and it’s not aerobic. What do you think that’s an indication of? If you had to play private investigator in this, what similarities do you think are having this effect?
Sara Lazar: That’s a good question, and they don’t really understand why exercise impacts brain structure. There’s blood flow and something called brain-derived neurotropic growth factor. There is a mental training component to the exercise because you have to practice daily, and there’s a certain amount of willpower, and executive control functions. That’s a little bit true with meditation as well because again, you have to get yourself there, and you have to get yourself to sit every day. Then while you’re sitting and practicing, your mind starts to wander off. It’s called meta-awareness. You have to be monitoring what your mind is doing to make sure you’re staying on track. And then when it does wander off, you have to remember, “Oh yeah, I gotta bring it back.” And there’s a couple of instructions to help keep you focused and with the right mindset. So again, it’s sort of an executive function kind of task. It’s not just passively sitting there doing nothing. There’s also some evidence that similar to exercise, you can get increases in brain-derived neurotropic growth factor.
Being Patient: What does that mean exactly?
Sara Lazar: Oh, so it’s basically a hormone. It’s a growth hormone in the brain, and that seems to help with neuroplasticity.
Being Patient: Did you also study the impact of yoga on the brain?
Sara Lazar: We’ve done a little bit with yoga. We did another study where we looked at long-term meditators and yoga practitioners because that’s always the question I get. People say, “Well, you know, I don’t meditate but I do yoga.” We took long-term yoga practitioners, long-term meditation practitioners, and what we found is that for the most part, they look very similar to each other. There are some subtle differences, but for the most part, they look very similar. We chose a very mindful form of yoga, but again, with the exercise analogy, it’s sort of like swimming versus running versus golf. All of them are going to have general cardiovascular benefits but there are subtle differences between them in terms of exactly which muscles are built up, and strength training versus cardio is a little bit different, these sorts of things. So it does seem like the different types of yoga and meditation will have some unique benefits but also some common benefits.
Being Patient: I always thought that with yoga, if we do inversions, meaning the positions where our head is facing down, that’s supposed to be good as well because it’s sending more blood flow to your brain. Is that too simplistic?
Sara Lazar: Yeah, a little bit, but that’s not bad. There is definitely evidence that just getting blood into the brain is beneficial, right? It’s going to be beneficial but that’s probably going to be more of a general effect across the whole brain as opposed to specifically for a few regions.
Being Patient: Where is the research on this subject headed? Tell us a little bit about that and what we’re learning about meditation.
Sara Lazar: In our random study, we looked at fear conditioning. When most people think about conditioning, they think about Pavlov’s dogs, right? You know, you hear a bell and get food, and then they start salivating to the bell. We did the same thing but with a painful shock. The participants in this study saw a light and got a painful shock, and they learned that the light represented getting shocked, and then we showed them the light but we didn’t shock them, so they learned that the light was okay. The key thing was then on day two. We brought them back the next day and showed them the light but we didn’t shock them. The question is, how do they respond to that light? What we found is that they were better at remembering that the light meant that they weren’t getting shocked, which is more consistent with a healthy response as opposed to people with anxiety tended to respond like they’re getting shocked again.
Also, it was really cool, what we found was that the hippocampus was more connected to the area of the hand where they were getting the shock, and that this was very strongly related with stress reduction and with anxiety levels. The idea is that if they were remembering that they weren’t being shocked, they were actually being mindful of their hand while they were being shocked, and not being shocked, and remembering that, which is really beautiful and interesting because it shows that yes, they were doing what they were being told to do. But they weren’t actually told to meditate or we didn’t tell them how to do anything. They just went through the shock experience and we didn’t give them any instructions on how to do it. They naturally, spontaneously became more mindful of their hand while they were being shocked and not shocked.
Being Patient: That exhibits that the brain has so much control over the body, what we feel and how we interpret that. Is there any reason to believe that meditation would be good if you’ve already been diagnosed with MCI or Alzheimer’s disease?
Sara Lazar: Yeah, there’s been several studies demonstrating that for early Alzheimer’s, the very mild cognitive impairment stage, there are some changes in brain structure and function, including the hippocampus. There’s also some slight gains in some cognitive tests. There was one study, it was a year and a half, I think there was a two-year study in the Canary Islands. They actually saw a reversal of symptoms. They found people having improvements in their cognitive scores, which was really fantastic. So there was no brain imaging in that study so it really needs to be replicated. Right now, we’re just recruiting people for a study to do a six-month study of mindfulness. We’re recruiting participants who have MCI.
Being Patient: Have there been any studies on the impact of tai chi on the brain?
Sara Lazar: We have one tai chi study with depression showing there’s changes in the insula, or the ability to pay attention inside your body. That makes a lot of sense because tai chi is all about filling your body, but also sending energy, so yeah. Again, sort of like running versus swimming, in that there’s going to be similarities and differences.
Being Patient: Can practicing yoga and meditation impact how much inflammation is in our brain?
Sara Lazar: There’s definitely some indications that yes, yoga and meditation can help with that. Also, you’re less stressed, and we know that stress contributes to inflammation. So even if it’s not actively reducing inflammation, it’s going to help prevent it developing in the future.
Being Patient: How did you compare people who meditated and didn’t meditate in your study?
Sara Lazar: Half the group went through mindfulness training and the other half was on a wait list. Then after eight weeks, they went into the class. And so we have that as a control. It is very important to have controlled conditions in these studies.
Being Patient: Yeah, absolutely. Will you be testing different types of meditation or can we just assume that mindfulness does the trick?
Sara Lazar: Again, sort of like with running versus swimming, they’re all going be good. There’s been a couple of studies with compassion meditation, which has also been shown to have very beneficial effects. There have been a couple studies with transcendental meditation as well. We did one study where we compared a relaxation response to mindfulness to show that there’s some similarities and differences but there’s not been a study comparing mindfulness to mantra meditation, and that would be good to do.
Being Patient: Tell us a little bit about what you looked at in your most recent study.
Sara Lazar: We’re just finishing up, so hopefully, we’ll be publishing it soon. We focused on healthy people between 65 and 80 years old and asked the question, can older people benefit from meditation, similar to how younger people benefit? That will be coming out soon, and like I said, we’re just starting to recruit people with MCI. Hopefully, we’ll see what’s happening there, so stay tuned. Then we’re just really interested in general in cognition, so how meditation influences memory, and attention, and other executive functions. So we’re trying to do some more studies with that.
The Lazar lab is currently recruiting individuals with mild cognitive impairment (MCI) for a study to test the effect of meditation on dementia-related symptoms. For more information, please write BrainTrain@mgh.harvard.edu, or call (617)-643-7271.