How Can Exercising Improve Your Lymphatic System?
The human body continuously works to maintain equilibrium in response to internal and external environmental changes. This includes the continual monitoring of bacterial and viral pathogens. These pathogens are kept at bay through the lymphatic system, which is stimulated and maintained by exercise. Over time, exercise has become associated with weight loss rather than health benefits. This paper will elucidate the role of exercise on lymphatic function in attempts to acquire more respect for a system often neglected by dominant perspectives within biomedicine.
Exercise is essential for good health. However, the Centers for Disease Control and Prevention (1999) states that more than 60% of adults do not achieve the recommended amount of regular physical activity and 25% of adults are not active at all (Figure 1). The Surgeon General also states that regular exercise reduces the risk of dying from heart disease, reduces the risk of developing high blood pressure, promotes psychological well-being, and helps build and maintain healthy bones, muscles, and joints. Despite this information, there is a growing trend among adolescents and young adults toward a more sedentary lifestyle (Figure 2). Regular exercise has many benefits to our health, and may play a larger role in disease prevention than we might realize.
The lymphatic system is a very important part to overall health. Largely ignored in the Western medicine model, the lymphatic system is composed of over 600 nodes that are dispersed throughout the body (Buckley 2007). These nodes, along with lymph, lymphatic vessels, lymphoid organs, and lymphatic tissues, work together to help the body to defend itself against disease (Innvista 2005). Lymph is composed of proteins, fats, red blood cells, and white blood cells, especially lymphocytes which attack bacteria and viruses in the blood. Lymphatic vessels branch into all tissues of the body, including nervous tissue, muscle tissue, connective tissue, and epithelial tissue. Lymphatic vessels carry lymph from peripheral tissues to lymph nodes, tonsils, the spleen, and thymus to meet a dense collection of lymphocytes, which can multiply to attack foreign agents (Figure 3). Unlike the circulatory system which uses the heart as a pump, the lymphatic system must rely on intrinsic and extrinsic factors to drive lymph formation and lymph transport. While intrinsic mechanisms involve spontaneous, intermittent contraction of the smooth muscle that lines the contractile lymphatic vessels, extrinsic mechanisms encompass active and passive body movement, pressure changes associated with respiration, and the pulse of nearby arteries (Lane et al. 2005).
While many of these processes seem mechanical, individuals have the capability to manipulate and enhance lymphatic flow through massage and exercise. Casey-Smith (2000) suggests that the effects of massage, compression, exercise and benzopyrones on lymphoedema were related to or enhanced by massage. Lymphoedema occurs when the lymphatic transport capacity is decreased, which can be due to lymphatic destruction by surgery, radiotherapy, or a genetic lack of vessels. Lymphoedema patients who experienced massage only experienced less infectious attacks than those without any massage treatment. This raises the possibility that involuntary muscle movement promotes lymph flow, and massage treatment may be important in healing as well as disease prevention. More research should be done to determine the specific infections that massage inhibits.
While massage can be useful, the most common way skeletal muscle is expanded and contracted is through natural body movement. Muscle contraction promotes the flow of lymph to various lymph nodes throughout the body. According to Lane et al. (2005), lymph flow increases by approximately 2- to 3-fold while exercising when compared to rest.
How can we know that lymph flow is increasing during exercise? The most direct way of measuring lymph flow is by cannulation of a lymphatic duct, which has been used in the past to measure the effects of exercise on lymph flow in horses, sheep, and dogs. However, lymphoscintigraphy is more commonly used for humans due to its more practical and less invasive nature (Lane et al. 2005). Stanton et al. (2001) used this method to investigate the effects of exercise on BCRL. While exercise did not aggravate the lymphoedema, it did not improve lymph clearance either. It is possible that exercise may be important in preventing lymphoedema, but more research needs to be done to demonstrate this.
Lymphoscintigraphy has been used to research other aspects of the lymphatic system as well. Havas et al. (1997) investigated the effects of muscle contractions on lymph clearance between four sedentary and four endurance-trained males by interstitially injecting albumin into the vastus lateralis muscles of the men. They then had them perform 100 submaximal contractions in 10 minutes where each exercise bout was separated by 65 minutes of supine rest. The albumin clearance rate was low during the resting periods, though higher in the trained individuals compared to the unconditioned subjects. Overall, the results showed lymphatic clearance rates nearly 2-fold higher among endurance-trained versus sedentary subjects during exercise periods. How can an endurance-trained individual demonstrate a higher clearance rate? Havas et al. suggests that trained individuals have a higher capillary density, which means more filtration and therefore a rise in interstitial pressure. This rise in pressure facilitates the entry of fluid and proteins into lymphatic capillaries.
Likewise, Cunha et al. (2004) proposes that training increases immune response in malnourished rats by producing gamma-interferon and interleukin-1. This study postulates how individuals should perform in a food restricted environment, suggesting that exercise may enhance immune function. However, exercise may only enhance immune function temporarily. It is possible that a food restricted environment is a stress induced pro-inflammatory response that may cause long term damage. While some studies associate exercise with enhanced immune function, other research suggests that not all exercise regimes demonstrate lymphatic efficiency.
In 1969, physicians Brunner and Fleischlin (1992) developed seven body exercises that support the natural drainage function of the venous and lymphatic reflux system. While these exercises have been modified, these exercises are still practiced today to enhance immune function.
Is the relationship between amount of exercise and lymphatic function linear? Several studies suggest that it is not. Boudreau and Hoffman-Goetz (2006) used mice to evaluate the effects of strenuous exercise on submandibular lymphocytes. The mice that had been subjected to strenuous exercise showed a lower number of submandibular lymphocytes when compared to age-matched mice not given access to running wheels. This implies that strenuous exercise may depress the effectiveness of the lymphatic system.
Seeking similar information, D.C. Nieman and S.L. Nehlsen-Cannarella (1991) explored the effects of acute and chronic exercise on immunoglobulins. When athletes run 45 to 75km at high intensities, serum immunoglobulin levels (antibodies) can be depressed for up to 2 days after exercise. This suggests that ultramarathon running may lead to greater and longer lasting decreases in serum immunoglobulin levels than following short bouts of exercise. Interestingly, moderate exercise training, defined as 45 minutes of brisk walking, 5 sessions per week, was associated with a net 20% increase in serum immunoglobulins in comparison to a control group during a 15-week period. This increase in serum immunoglobulin was also associated with a lower total acute upper respiratory tract symptom days. While psychosocial and physiological stresses coupled with competitive exercise may be correlated with depressed serum immunoglobulin levels, moderate exercise training may lead to higher antibody levels with contrasting effects on risk of infection. These studies reveal the complexity of the lymphatic system and its manipulation by exercise. More exercise is not necessarily better, which is a common misconception.
This evidence is relevant to breast-cancer survivors, where 27-49% of female survivors have depressed immune function due to the removal or ineffectiveness of lymph nodes. Axillary lymph node examination is crucial to diagnosing breast cancer, and 10-30 of these lymph nodes are usually removed to determine the stage of cancer. Removing these lymph nodes causes swelling among some patients because drainage of lymph from the arm is disrupted and/or blocked when the number is axillary lymph nodes are reduced. Chronic swelling occurring in the hand or arm of women treated for breast cancer is very common, and is known as BCRL (Breast Cancer-Related Lymphoedema). Due to the decreased number of functioning lymph nodes, lymph fluid collects in the arm or hand of the affected individual and often the lymph must be manually removed to reduce swelling associated with this accumulation. In the past, many physicians have recommended survivors of breast cancer to avoid vigorous upper body exercise for fear of promoting or worsening BCRL. However, Lane et al. (2005) proposes that there is a possibility that exercise may be useful in the prevention and treatment of BCRL and various researchers have recently investigated this possibility.
The abundance of research on exercise and health reflects an interesting part of North American culture. While American culture is tending toward a more sedentary lifestyle, it is also true that North American popular culture can be characterized by its obsession with fitness and exercise (Phillips 2005). According to Jeremy Howell (1991), American consumers spend billions of dollars annually on exercise products including health club memberships, whey supplements, yoga videos and zip-up sneakers. American culture is obsessed with the idea of exercise and many people associate exercise with morality. Barbara Phillips (2005) investigated this phenomenon by interviewing three male and three female exercisers who were recent college graduates. These participants met the minimum government standard for regular physical activity, defined as a half-hour of light to moderate exercise at least five times per week, and the subjects were between the ages of 23 and 30 and had body weights average for their heights. Participants were asked to describe what qualified as successful exercise, the reasons they liked and disliked exercise, and preferences on working out alone or in a group in addition to other questions. These men and women characterized individuals who do not exercise as people who are not concerned with health and associated them with drinking too much, smoking and breathing heavily. One participant stated that “nonexercisers are more likely to die earlier than me.” The more Phillips questioned the subjects, the more morality-based their answers became. A male exerciser felt that those who do not exercise never learn to challenge themselves in life. While they felt “virtuous” when they exercised, participants stated that when they were unable to work out, they felt “frustrated, irritable, grumpy, mean, out of sorts, stressed, tired, sluggish, and miserable.” This reaction implies that regular exercisers are motivated by social and psychological benefits rather than their personal health.
So if Americans are so obsessed with exercise, why do statistics show a growing trend toward a more sedentary lifestyle? (CDC 1992) The goals of exercise vary widely between people. Many forms of media present health and exercise as a means to achieving beauty. The message is that you should exercise to lose weight to be more accepted in society. Following this logic, if you have a body weight that is average for your size, then you do not need to exercise. Exercise is associated with weight loss, not immune function, cell metabolism, or disease prevention. Exercise has evolved as a chore, something that is not enjoyable but must be done, rather than a lifestyle. And this progression is inevitable based on humans’ transition from forager to farmer to a more sedentary lifestyle. Humans’ access to food has become more convenient with well-stocked grocery stores and cars. Therefore, body movement is no longer necessary for survival in a direct sense. However, as far as lymphatic function is concerned, it is more necessary than people may realize. While it’s true that we no longer have to keep up with a migrating group of animals or even harvest our own food, the human body is still very dependent on muscle contraction and expansion for the circulation of nutrient-containing fluids throughout our bodies. How has this concept become overshadowed?
In the last 50 years, America has made a transition toward high sodium, processed foods. Fast food restaurants have become one of the easiest and cheapest ways to eat, and combined with less labor intensive occupations and plentiful food supplies, many Americans have become overweight. Obesity and general high body fat content have become heavily emphasized (no pun intended) in the media and have defined this body type as unhealthy. While being overweight is in fact unhealthy for most people, this does not mean that just because someone has a normal body weight for their height they are indeed healthy. Weight has become a marker for health status, and thin people are often assumed to be healthy because they fit the media’s ideal body type. As a reaction to obesity trends, many Americans have integrated exercise into their personal morals.
The lymphatic system’s efficiency can be enhanced with moderate exercise due to increased lymph propulsion. Massage has also shown to be effective in increasing lymph flow. This information is relevant to people of all body types because the immune system is dependent on body movement in all individuals, and is not automatically efficient in those with a normal weight to height ratio. More research could be done to evaluate if psychological well being and general attitude have any implications for immune function.
Boudreau, J. and Hoffman-Goetz, L.
2006 Long-duration freewheel running and submandibular lymphocyte response to forced exercise in older mice. Canadian Journal of Physiology and Pharmacology 84(5):565-572. The purpose of this study was to evaluate the effects of strenuous exercise on submandibular lymphocytes. Mice that had been subjected to strenuous exercise showed a lower number of submandibular lymphocytes when compared to age-matched mice not given access to running wheels. This is important to my analysis because this study indicates that while moderate exercise may enhance lymphatic efficiency, strenuous exercise depresses its effectiveness.
Brunner, U. and Fleischlin, C.
1992 1992 Update on the value of exercise for treating venous and lymphatic congestion. VASA-Journal of Vascular Diseases 21(2):206-209. This article discusses seven body exercises that support the natural drainage function of the venous and lymphatic reflux system. This is a system developed in 1969. It is relevant to my topic because I am interested in how these exercises increase lymph flow and their overall effect on health.
The Lymphatic System – Another Reason to Exercise. Electronic document, http://www.byregion.net/articles-healers/Exercise_Lymphatic.html, accessed May 7, 2007. Lorelei Buckley is a Naturopathic Doctor and Certified Applied Lymphologist. In this document, she states that exercise and massage increases lymph movement. Stagnation of inguinal nodes may lead to a higher occurrence of infection. Buckley also describes where collection sites are located (where you have dense collections of lymph nodes).
2000 Changes in the microcirculation at the superficial and deeper levels in lymphoedema: the effects and results of massage, compression, exercise and benzopyrones on these levels during treatment. Clinical Hemorheology and Microcirculation 23(2-4):335-343. This essay microscopically examines the changes that occur in lymph flow during distress and how typical treatments can possibly repair malfunction as in the case of lymphoedema. I am going to focus on the effects and results of massage and exercise in relation to lymph flow, since these topics specifically deal with muscle movement.
Centers for Disease Control and Prevention
1996 A Report of the Surgeon General: Physical Activity and Health. Electronic document, http://www.cdc.gov/nccdphp/sgr/ataglan.htm, accessed May 7, 2007. The CDC is a collective group of institutions that conduct research and provide knowledge to the public regarding current health issues. This document discusses the benefits of regular exercise, examples of moderate exercise activities, and national statistics on the average activity levels of adults and teenagers. The website also discusses exercise accommodations for people with special circumstances such as being on a diet or having high blood pressure.
Cunha, W.D., Giampietro, M.V, De Souza, D.F., Vaisberg, M., Seelaender, M.C, and Rosa, L.F.
2004 Exercise restores immune cell function in energy restricted rats. Medicine and Science in Sports and Exercise 36(12):2059-2064. This study suggests that when rats are malnourished, training increases their immune response by producing gamma-interferon and interleukin-1. Training did not interfere with the body’s natural diversion toward a Th-1-type immune response in a food restricted environment. This is relevant to my analysis because it explains how training might affect lymphatic efficiency and also brings to mind that other factors must be considered, such as energy intake.
Havas, E., Parviainen, T., Vuorela, J., Toivanen, J., Nikula, T., and Vihko, V.
1997 Lymph flow dynamics in exercising human skeletal muscle as detected by scintography. The Journal of Physiology 504(1):233-239. Havas et al. investigated the effects of dynamic and isometric muscle contractions on lymph clearance using lymphoscintigraphy, comparing sedentary and endurance-trained males. The lymphatic clearance rates between exercise conditions was almost 2-fold higher in the endurance-trained versus sedentary subjects, possibly due to increased capillary density among trained individuals. A dense capillary network means more filtration and therefore a rise in interstitial pressure, which facilitates the entry of fluid and proteins into lymphatic capillaries.
2005 The Lymphatic System. Electronic document,
http://www.innvista.com/health/anatomy/lymphat.htm, accessed May 7, 2007. This website gives information about the basics of the lymphatic system such as its main functions and definitions of lymph, lymphatic vessels, lymphoid organs, and lymphatic tissues. I will use this in my paper to give a general overview of the lymphatic system and its main components.
Lane, K., Worsley, D. and McKenzie, D.
2005 Exercise and the lymphatic system – Implications for breast-cancer survivors. Sports Medicine 35(6):461-471. This journal article summarizes current research on the lymphatic system related to exercise while also examining the implications of these findings for breast-cancer survivors, such as lymphoedema. Authors state that lymph flow increases by approximately 2- to 3-fold higher while exercising than at rest. This article is useful for the development of my paper because it covers current research findings up to 2005 and the role of the lymphatic system during exercise.
Minono, A., Heron, M., Murphy, S., and Kochanek, K.
2007 Deaths: Final Data for 2004. National Center for Health Statistics. Electronic document, http://www.cdc.gov/nchs/products/pubs/pubd/hestats/finaldeaths04/finaldeaths04.htm, accessed May 7, 2007. The National Center for Health Statistics is part of the CDC and provides information about current health issues such as tooth decay, infant mortality, and leading causes of death in the United States. The former is what I will use in my paper.
Nieman, D.C and Nehlsen-Cannarella, S.L.
1991 The effects of acute and chronic exercise on immunoglobulins. Sports Medicine 11(3):183-201. A scientific study that shows increased immunoglobulin production after brief graded maximal exercise, short term submaximal exercise, and moderate exercise training (45 minutes of brisk walking 5 times per week). The results also show depressed immunoglobulin levels for up to 2 days after athletes run 45-75km at high intensities. Nieman and Nehlsen-Cannarella conclude that competitive exercise training depresses immunoglobulin levels while moderate exercise training slightly increases immunoglobulin levels with contrasting effects on risk of infection.
2007 The Lymph System and Your Health. Electronic document, http://www.womentowomen.com/detoxification/lymphaticsystem.asp, accessed May 7, 2007. An internet document that details information about the lymphatic system such as anatomy, lymphatic massage, and the advantages of regular exercise on lymph flow. In addition, this document also contains a useful image of the components of the lymphatic system that I will include in my paper.
Stanton AW, Svensson WE, Mellor RH, et al.
2001 Differences in lymph drainage between swollen and non-swollen regions in arms with breast-cancer-related lymphoedema. Clinical Science 101(2):131-140.