What is lymphatic drainage, anyway?

A new wellness trend focuses on stimulating the lymphatic system. What does this system do, and is there science to back these claims?

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  WNYC is supported by Bayer. Science is about asking questions, testing, trying again. It's not easy, but it's relentless. It evolves, and that's why science delivers. Learn more at sciencedelivers.com.

• 0:17Flora Lichtman?

  Hey, it's Flora, and you're listening to Science Friday. A new wellness trend focused on an obscure capillary system that moves fluid around the body has been bubbling up, and you all wanted to know more.

• 0:33Speaker 02

  I am calling with questions about lymphatic drainage.

• 0:36Speaker 03

  In regards to lymphatic drainage, I'm not even quite sure what that means.

• 0:42Speaker 02

  I heard that jumping on a rebounder helps your lymphatic system work better and you feel more healthy.

• 0:50Speaker 03

  I've gotten a lymphatic drainage massage before, and I didn't really feel any different.

• 0:56Flora Lichtman?

  Lymphatic walking, vibration plates, compression boots, all have been touted as ways to stimulate the lymphatic system to combat bloating, flush away toxins, and generally promote health. So let's dive in. What is the lymphatic system? What does it do in the body? And is there anything to these claims? Here with answers are two experts. We have Dr. Timothy Padera, researcher at Mass General Research Institute, who's dedicated his career to better understanding how the lymphatic system works, and physical therapist Dr. Mark Miller, who treats cancer patients with manual lymphatic drainage at UTMD Anderson Cancer Center.

• 1:40Flora Lichtman?

  Tim, Mark, welcome to Science Friday.

• 1:42Speaker 04

  Yeah, thank you for having me.

• 1:44Speaker 05

  Yeah, ditto, thanks.

• 1:45Flora Lichtman?

  Thank you for being here. Tim, let's start with some 101. What is the lymphatic system, and what does it do?

• 1:53Speaker 04

  So the lymphatic system really is comprised of many different types of vessels that are all throughout our body. They cover the surface of our brain, they're in the tips of our toes, they're sort of pretty much in every tissue in between. And they also contain critical organs for generating our immune responses called lymph nodes. And there's really three main functions for the lymphatic system. The first is, it really does help maintain our fluid levels in our tissues. And so some of the smaller lymphatic vessels will sit in the tissues, absorb fluid, and that gets collected by larger vessels that end up returning that fluid, called lymph, back to the blood.

• 2:38Speaker 04

  A second main function is that the lymphatic system kind of forms communication between our tissue and our immune system. And so as those small vessels are taking up the fluid from the tissue, they can also pick up bits of bacteria, or virus, or any other infection in immune cells. And they bring that information to the lymph nodes, so lymph nodes can then determine whether they need to mount an immune response to anything, any sort of infection that might be happening. And then the third main function is the lymphatics in our gut are really important for absorbing our dietary lipids.

• 3:18Flora Lichtman?

  That's interesting. It seems to have varied roles. And so these vessels, they're not blood vessels, they're a different kind of vessel?

• 3:26Speaker 04

  They are a different type of vessel. So the blood circulation is sort of referred to as closed, like we want to keep the blood in the blood vessels. And so the blood circulation also has this nice central pump on it, we call it the heart, where the lymphatics really are just going one direction. They're going from the tissue to the blood, but it's not the blood coming really back in a closed system, back to the lymphatics, right? So it's more like the roots from a tree absorbing fluid and bringing up to the trunk of the tree. And because there's no central pump to actually move the fluid, the larger vessels have their

• 4:09Speaker 04

  own muscle and can contract and actually drive the lymph flow back toward the blood circulation.

• 4:15Flora Lichtman?

  Tim, what is lymph? What's the definition?

• 4:18Speaker 04

  So I always say all lymph is local. Lymph is just the stuff in your lymphatic vessels, and it's comprised of whatever's in the tissue. So if you have inflammation in the tissue, it's going to be picking up all those inflammatory signals, bringing it to the lymph node. If you've been fasting for a long time, the lymph in your gut is going to look very different from if you've just eaten, you know, a cheeseburger, right? Because then you're going to get a lot more lipids into that lymph. And so it's a very dynamic fluid, and it's all sort of depends on the tissue it's draining. You know, at any moment, lymph in different parts of your body is comprised of different things.

• 4:59Flora Lichtman?

  Mark, you're a physical therapist, and you focus on this. You know, I think of the physical therapy as sort of rehabilitation for my back injury or my knee problem. What does it mean to be a physical therapist for lymphatic drainage?

• 5:15Speaker 05

  It can mean a variety of things, depending on your setting. For myself, I work in an oncology setting. 98% of my patients are cancer patients, primarily breast is what I specialize in, but I do a lot of lower extremity as well. So my job is to help educate patients on the lymphatic system, to help bolster the lymphatic system through massage and compression, teach patients safe exercise to not increase swelling, and not strain the lymphatic system, and just to try to restore as much quality of life as possible after treatment for cancer, especially when that cancer affects the lymphatics.

• 5:58Flora Lichtman?

  Mark, why do cancer patients need manual lymphatic drainage?

• 6:02Speaker 05

  Yeah, so the number one cause of lymphedema, or a collection of lymphatic fluid into the tissues in the world, is a parasite called phleuriasis. Very common in Southeast Asia and some other locations. But the number one cause in America of lymphedema is treatment for breast cancer. So when lymph nodes are removed as a result of surgery, when they are damaged as a result of radiation that might be received, or even some types of chemos can start to flatten out the walls of the lymphatic vessels and decrease the contractility of those vessels, and not allow them to send the fluid back to the circulatory system like they should.

• 6:44Speaker 05

  Manual lymph drainage can help redirect that fluid in a positive manner and decongest some of those tissues and stimulate the lymphatics that are still functioning.

• 6:52Flora Lichtman?

  What does lymphatic drainage mean?

• 6:55Speaker 05

  Manual lymphatic drainage is a very, very light massage used to stimulate the lymphatic vessels that were just being discussed, to help direct the lymphatic fluid back to the circulatory system in the most expedient manner. You know, it was kind of really kind of put out there by influencers and celebrities. I think Jennifer Lopez was one of the first ones to kind of say, like, I'm going to get a manual lymphatic drainage massage. It's great for my skin, and it's great for a variety of other things.

• 7:24Flora Lichtman?

  You said light massage. What does it feel like?

• 7:27Speaker 05

  It feels like a skin stretch. So if you were to just move the skin enough to stretch it or to wrinkle it, and then let it snap back, that's about the pressure that we're using. So it's incredibly light. People have used other analogies like gently petting a kitten, or moving the skin on a baby's head. Those are some other examples that have been used to try and teach the pressure, which can be difficult to master. Most of my patients ask me, is this actually doing anything? And we actually have studies that have been done at MD Anderson under a special type of camera that we can inject a dye and actually follow the lymphatic fluid through these vessels and actually see it moving.

• 8:10Speaker 05

  So we know that the massage is actually moving the fluid through the vessels.

• 8:14Flora Lichtman?

  Is there any benefit for people who don't have an illness related to the lymphatic system, like lymphedema, or had their lymph nodes removed? Like, is this helpful for healthy people?

• 8:28Speaker 05

  To my knowledge, there's no disadvantage to doing it. I'm not familiar with any research that is currently out there saying that, yes, by doing manual lymph drainage on healthy individuals, it's promoting X, Y, and Z. For manual lymphatic drainage has been used in sports recovery in the past, to help flush out some of the inflammatory markers that were previously being discussed, to help expedite recovery, to help decrease edema and inflammation in joints and in muscles, help flush out lactic acid, things along those lines. So in those particular cases, there has been research saying that it's helpful, but just

• 9:13Speaker 05

  Joe or Jane Smith going to a massage parlor and getting a manual lymphatic drainage from a certified lymphedema therapist, I'm not aware of any studies out there that show a significant benefit in, say, skin health or anything along those lines.

• 9:28Flora Lichtman?

  Tim, a lot of the lymphatic hacks online have to do with deep bloating. Does that have anything to do with your lymphatic system?

• 9:37Speaker 04

  So I would say probably what's more important is the origin of where the bloating is originating, whether it's from inflammatory processes that are giving you the sense of that feeling of bloating, which could include more fluid, or other things that are causing it, maybe your diet, lack of sleep, can all sort of cause that. So it's not necessarily that the lymphatics aren't working or working properly that's leading to the bloating. Now, lymphatics are good at removing fluid, so potentially stimulating lymphatics might remove some of that fluid and remove that sensation.

• 10:20Speaker 04

  But it's probably best also think about the underlying causes for the bloating.

• 10:25Flora Lichtman?

  Mark, I have to ask, because we had a bunch of calls about it, what's the deal with these vibrational plates? Do they do anything? Should we all be bouncing?

• 10:36Speaker 05

  Look, in the lymphedema world, we have heard just about everything. Dry brushing used to be a big thing back in the day. Vibration plates used to be a big thing. Rebounding used to be a big thing. There's no research to absolutely suggest that vibration plates improve lymphatic function. There's no research to suggest rebounding improves lymphatic function. I think what people typically get from the vibration plates and what people typically get from the rebounding is they're getting the muscle pump. And because the superficial lymphatic vessels are so superficial, they're only a couple of millimeters underneath the skin. You're getting that muscle pressing up against the skin. You're getting that fluid being pressed up towards the heart,

• 11:21Speaker 05

  back towards the circulatory system, as was previously mentioned. And I think it's probably helping in that area. But there's not been any research to show that no vibration plates or rebounding are actually beneficial in and of itself in isolation for the lymphatics.

• 11:37Flora Lichtman?

  You know, this seems like an important system. I mean, obviously, it's having a little bit of a moment online. But do you feel like it gets the recognition it deserves in the medical or research world? And I'd love to hear from you both on this.

• 11:49Speaker 04

  So it has been interesting that the field of of understanding in the lymphatic system is really far behind what we know for the cardiovascular system. And I would say it was about the 1990s has sort of been the resurgence of lymphatic biology. And I think we're sort of now at a very unique time because we're starting to learn a lot more, where we might start to be able to develop therapies for a lot of the different lymphatic diseases, lymphedema being one. But there's other diseases where lymphatic function could be improved that might help in a lot of different situations. There's been a lot of research recently

• 12:34Speaker 04

  on lymphatics that drain the brain and the role it might help in removing waste from the brain. And so you start thinking about things like neurodegenerative diseases such as Alzheimer's. People have been looking into the inflammation that occurs after traumatic brain injury and potentially by stimulating more lymphatic function, being able to remove that to improve outcomes. Beautiful work on migraine headaches as well. And it's not just in the brain. These are all sort of diseases. There's been beautiful work looking at lymphatic drainage in the heart after myocardial infarctions. And so I feel like we're in this sort of window. It's interesting that it's coming on

• 13:18Speaker 04

  sort of online as with the same time as a lot of these therapies are starting to potentially emerge. And obviously, more research is needed. But for me, it's a really exciting time.

• 13:28Speaker 05

  Yeah, and I'll just piggyback on that. I'm just extraordinarily blessed to work with a plastic surgeon, MD Anderson, who this is his, this is a big part of his practice, a big part of his focus. We are developing surgical techniques for lymphedema to help restore this. And not only that, but in addition, we're doing a lot of the immediate lymphatic reconstruction and trying to bypass the lymphatics that are no longer there at the time of surgery. So this swelling doesn't have a chance to occur. So a lot of these people hopefully never need to get to me and never need to see me. And that's becoming more of the norm now. And not only for breast, but for melanoma and some other things as well.

• 14:12Flora Lichtman?

  Dr. Mark Miller, certified lymphedema specialist and senior physical therapist at UT MD Anderson Cancer Center. Mark, thanks for joining us today.

• 14:20Speaker 05

  Thank you so much for having me. I appreciate it.

• 14:22Flora Lichtman?

  Tim, can you hang in the line? I want to ask you about what's next in the field of lymphatic medicine.

• 14:27Speaker 04

  Sure, be happy to.

• 14:37Flora Lichtman?

  Hey, everybody, if you like Science Friday, I want to recommend another podcast I know you'll love too. Science Versus. From peptides to protein maxing, Science Versus takes on fads and trends and the opinionated mob, I know you know what I mean, to find out what is fact, what is not, and what's something in between. And they're the only podcast with better pun game than us. So check them out, Science Versus, wherever you get your podcasts.

• 15:11Flora Lichtman?

  Tim, do we have any drugs that target lymphatic system conditions like lymphedema?

• 15:19Speaker 04

  No, and you know, to me, it's incredible. There are no FDA-approved drugs indicated to alter lymphatic function. And when you compare that to like the cardiovascular system, we have drugs that can increase your blood pressure, lower your blood pressure, increase your heart rate, lower your heart rate. And right now, we don't have anything for the lymphatic system. There's a lot of interest in doing so. And lots of research is being done to try and first understand how the lymphatic system works. And we're coming, you know, pretty far along in that. And now it's just about trying to develop molecular targets

• 16:03Speaker 04

  that can be drugs that can then improve lymphatic function.

• 16:07Flora Lichtman?

  I mean, you, Tim, you alluded to this, but are we yet harnessing the lymphatic system to help treat other kinds of conditions? You know, like, like the way that we harness the immune system to fight cancer?

• 16:18Speaker 04

  Yeah, no, so that's a, that's a beautiful question. Because there's theory on how improving lymphatic function, say, I sort of talked about brain drainage, might improve things like, you know, the accumulation of the amyloid proteins and tau proteins in Alzheimer's disease, right? That's a, that's theory right now. Because we actually don't have a tool to test whether increasing lymphatic function could really improve those disease outcomes. So to me, I think we're getting closer to being able to develop therapies that will show improvements in lymphatic function. We can then test them in sort of known lymphatic diseases like lymphedema, but also then think about them in these other disease processes

• 17:03Speaker 04

  where lymphatic drainage might really help improve outcomes and symptoms and maybe long-term prognosis for a lot of these conditions.

• 17:14Flora Lichtman?

  What is it like for you to work in this field? It feels like it's really still in its infancy.

• 17:18Speaker 04

  You know, you can, you can find a department of immunology at hospitals. You can find a department of cardiovascular medicine. Right now, there's no department of lymphatic medicine. And so I think there's a lot of opportunity to grow. You know, when I got into this field, we were sort of right at the cusp of learning a lot more about the lymphatic system from sort of how it works and the biology behind it. And to see the field develop over the last 30 years has really been incredible. There's tons of really smart scientists now that are invested in understanding the lymphatic system. You know, I'm optimistic of where we will see

• 18:02Speaker 04

  sort of lymphatics and lymphatic medicine develop over the next years.

• 18:07Flora Lichtman?

  Well, good luck.

• 18:09Speaker 04

  Thank you.

• 18:10Flora Lichtman?

  Dr. Timothy Padera, investigator at Mass General Research Institute and professor of radiation oncology at Harvard Medical School.

• 18:24Flora Lichtman?

  This episode was produced by Shoshana Buxbaum. Thank you to everybody who called in with your questions and your experiences. And if you have questions for us, give us a call. 8774 Sci-Fry is our number. I'm Flora Lixman. We'll catch you next time.