Disease/ Disorder
Definition
Exercise can be defined as a subset of physical activity that is planned, structured, and repetitive and has, as a final or an intermediate objective, the improvement or maintenance of physical fitness.1 Unfortunately, there is no consistent definition of the word “elderly” or “old age” from the standpoint of biology, employment, and retirement, and sociology; however, “old age” or “elderly” is frequently defined as age 60 to 65+ years of age.2 The American College of Sports Medicine (ACSM) defines older adults as individuals ≥ 65 years or adults aged 50 to 64 years with clinically significant conditions or physical limitations that affect movement.3 There are unique considerations that should be considered by a physiatrist when prescribing and advising older adults regarding exercise.
Etiology
Being familiar with the unique biomechanical and physiologic changes associated with elderly patients allows the physiatrist to adequately increase physical fitness levels safely in this patient population. These physiologic changes occur at a faster rate as we age, resulting in a reduction in function and quality of life. It has been shown that physical endurance in the elderly decreases as a result of changes in body fat composition, increased sedentarism with age, and deconditioning.4 It has also been shown that muscle strength decreases with age due to progressive muscle atrophy, impaired neuromuscular control, and an increase in non-contractile adipose tissue, all of which contributes to the conditions known as sarcopenia and frailty.5
Epidemiology including risk factors and primary prevention
Worldwide, the number of people over the age of 65 is expected to increase from approximately 900 million in 2015 to over a trillion in 2030.6 Despite clear benefits of exercise, 27.5% of US adults over the age of 50, approximately 31 million persons, self-reported as “inactive.”7 The prevalence of inactivity increased with advancement in age: adults aged 50-64 (25.4%), 65-74 (26.9%) and 75 years and older (35.3%).8 These compelling epidemiologic data suggest that without a significant change in the overall physical activity level of the baby boomer generation, an epidemic of sedentarism-related disease burdens in our society will increase exponentially. There are numerous studies demonstrating the positive effects on cardiovascular, metabolic, endocrine, psychological health and delayed decline in the elderly population.
Pathoanatomy/physiology
Physiologic changes occur in every organ system of the body as a part of the normal aging process, which lead to a decrease in exercise capacity. The following physiologic changes are of specific concern for the elderly patient that would benefit from exercise
- Musculoskeletal – It has been shown that older aged people have decreased number of myofibrils and concentration of mitochondrial enzymes. Decrease in muscle strength by 15% per decade after age 50 and 30% per decade after age 70.9 Aging leads to an increased percentage of type I muscle fibers due to type II muscle fiber atrophy.10,11 Bone mineral density also tends to peak by the 3rd decade of life, then decreases by about 0.5% per year after the age of 40.12 Bone density loss is further exaggerated post-menopause.12
- Cardiovascular – Cardiac aging is associated with progressive loss of myocytes and compensating mild hypertrophy, and reduced sensitivity to sympathetic stimuli. In addition, older patients also experience increased left ventricle and systolic volume and decreased ejection fraction during exercise.13 These physiologic changes ultimately lead to decreased peak cardiac output and maximum heart rate response to exercise. Maximum age-related heart rate can be estimated by subtracting 220 from the patient’s age5. In addition, older aged patients are more susceptible to orthostatic hypotension, because the baroreflex is impaired by atherosclerosis.14 VO2 Max naturally declines with age by about 5-15% per decade.15
- Pulmonary – From a pulmonary function standpoint, elderly patients tend to have decreased maximal oxygen consumption, forced expiratory volume in 1 second (decreased consistently 30cc/year starting at age 35-40 years), vital capacity, carbon monoxide diffusing capacity, and maximum minute ventilation). In addition, they experience an increase in residual lung volume and functional residual capacity due to decreased chest compliance and air trapping.16
- Gait – Gait instability tends to by the 4th to 5th decades of life.17 Overall, gait pattern in the elderly is characterized by slower walking speed, increased time in double limb support and stance phase, greater stride width variability, and shorter stride length.15,18,19 Multiple factors affect the gait cycle in the older patient such as changes in vision, sensation, balance, neurocognition, strength, joint health, metabolism, and adaptive changes related to increased caution or anxiety.15,18
Although these changes may represent normative aging, the rate of progression can be altered by engaging in a regular exercise program.20 Positive physiologic changes from exercise can be summarized below
- The benefits of the aerobic exercise components include improvement in VO2max which leads to lower heart rate at rest and during submaximal exercise, smaller increases in blood pressure, improved glycemic control and improved postprandial lipid metabolism.21
- Resistance training in the elderly leads to an increase in fat-free body mass, a decrease in total body fat and counteracts sarcopenia. There is also an increase in motor unit recruitment and discharge rates as well as muscular endurance.21 The combination of aerobic and resistance training in elderly adults without disabilities results in increased functional independence.
- Flexibility training in elderly adults has been shown to increase range of motion especially in the lumbar back region and knee flexors which allows for faster recovery from a perturbation, hence decreasing the likelihood of suffering a fall.21 Flexibility exercises have also been shown to reduce pain.
- Balance exercise programs are designed to improve neuromotor control of the lower extremities and improve the vestibular component which reduces the likelihood of falling.21
Together, these various components promote physiologic changes in an elderly adult. However, an added benefit to a physically active elderly person is improving feelings of well-being, mood and improved quality of life which lowers the risk of dementia and cognitive decline.22
Almost all elderly persons can benefit from an exercise program and few contraindications exist to implementation of physical activity. To avoid potential complications, and design a safe exercise program, any sedentary older individual should ideally undergo a full physiatrist evaluation before implementing a new exercise regimen.
Disease progression: natural history, disease phases/stages, and disease trajectory
When considering physiologic changes associated with aging, it is important to distinguish primary aging from secondary aging. Primary aging is the natural deterioration of the body that occurs over time with age. Secondary aging refers to the physiologic and functional changes that occur to the body over time as a result of extrinsic factors, such as disease or lifestyle.23 As primary and secondary physiologic changes progress with age, ultimately patients may develop conditions known as sarcopenia and frailty.
There are multiple research groups that have been working on a definition for the term Sarcopenia, including, but not limited to the European Working Group on Sarcopenia in Older People (EWGSOP) and the Asia Working Group for Sarcopenia (AWGS), etc. In 2018 the EWGSOP defined sarcopenia as a progressive and generalized skeletal muscle disorder characterized by low muscle strength, low muscle mass, and poor physical performance.24 Sarcopenia is thought to be driven by a combination of catabolic action and reduced anabolic influences, including inflammation, hormonal changes, and lifestyle or nutritional choices.15 Sarcopenia can be diagnosed utilizing the criteria summarized below24
Sarcopenia is also a key component of frailty. Like sarcopenia, frailty is often considered a physical disability in the elderly and often mistaken for a normal part of the aging process.25 This state is characterized by weakness, weight loss, exhaustion, a decrease of daily activity and accumulation of co-morbidities and is associated with worse long-term outcomes.25 There are multiple tools used to diagnose frailty, but the most common tool used is the Fried Frailty Tool, which is summarized below.15,26
Being elderly does not automatically lead to a diagnosis of sarcopenia or frailty despite the correlations, as there are many people who can maintain strength and functional independence into old age. Both sarcopenia and frailty are highly associated with disability in the elderly population, but both have also been shown to be modifiable.27 Much of the evidence shows that physical activity or exercise is highly recommended to modify frailty and its adverse outcomes.28
Specific secondary or associated conditions and complications
Most commonly seen complications of exercise are almost always due to exertional or overuse injuries such as muscle sprains and acute inflammation (e.g., tendinitis, bursitis) comprising 70-85% of total injuries, in the elderly.29 Appropriate training programs, use of safe and familiar equipment, careful warming up and cooling down, multiphasic training (including balance, coordination and reaction time) are essentials to prevent injuries.29 Regular follow-ups with a physiatrist throughout the patient’s participation in an exercise program can help prevent and mitigate these injuries. Other more commonly seen exacerbation of chronic conditions such as osteoarthritic joint pain and decreased range of motion, impingement, bursitis and tendonitis, all can discourage and limit adherence to exercise programs.
Essentials of Assessment
History
Obtaining a detailed and focused exercise history is essential to properly counsel exercising patients and functionally optimize sedentary patients prior to exercise. A thorough review of past medical history and medications can help guide the physiatrist to determine whether pre-exercise screening is recommended and when designing an exercise program.
The ACSM 10th edition guidelines for exercise prescription algorithm for pre-exercise screening is based on the patient’s physical activity level, signs and symptoms of and/or known cardiovascular, metabolic, or renal disease, and desired exercise intensity.3
- Physically Active Individual
- In the physically active individual who does not have or show signs/symptoms of cardiovascular, metabolic, or renal disease: medical clearance is not necessary.3
- In the physically active individual who is asymptomatic and does have a known history of cardiovascular, metabolic, or renal disease: medical clearance is not recommended for moderate intensity exercise but is recommended for vigorous intensity exercise.3
- In the physically active individual who shows signs/symptoms of cardiovascular, metabolic, or renal disease, regardless of disease status: all exercise should be discontinued until medically cleared.3
- Physically Inactive Individual
- In the physically inactive individual who does not have or show signs/symptoms of cardiovascular, metabolic, or renal disease: medical clearance is not necessary.3
- In the physically inactive individual who is asymptomatic and does have a known history of cardiovascular, metabolic, or renal disease: medical clearance is recommended.3
- In the physically inactive individual who shows signs/symptoms of cardiovascular, metabolic, or renal disease, regardless of disease status: medical clearance is recommended.3
It is also important to consider the many co-morbid illnesses that are common in the elderly population and determine whether these diseases or adverse medication effects are impairing the patient’s ability to participate in an exercise regimen.
Common conditions in the elderly population include30,31
Common medications in the elderly population include30,31
Additionally, it is important to understand a patient’s motivation for initiating an exercise regime so that it can be tailored to the patient. Identifying barriers to exercise is also key as it can affect exercise adherence.32 Musculoskeletal pain is a common barrier to exercise and one that is particularly amenable to intervention by a physiatrist.
Physical Exam
The physical examination of an older adult should be comprehensive with focused examination of the systems primarily involved in exercise. The heart and peripheral vasculature should be assessed to garner information about aerobic exercise capacity as well as identifying pathologies that may limit aerobic exercise tolerance such as peripheral vascular disease. Underlying cardiovascular disease may also be identified such as uncontrolled hypertension, unstable angina, third degree heart block or acute heart failure which would be contraindicated to exercise initiation in older adults.21 The respiratory system should also be examined, namely, to identify any pulmonary disorders such as chronic bronchitis, emphysema or restrictive lung diseases. The musculoskeletal examination involves examination of the axial and appendicular skeleton, with attention to posture, muscle bulk, joint range of motion and strength testing. Gait assessment should also be performed and an evaluation of static balance and fall risk may be assessed using the Berg Balance scale.21 Neurological testing should include vision assessment, sensation, proprioception and a mini-mental examination as these are all risk factors for falls. Psychological testing should also be assessed to provide insight on exercise motivation and goals and to identify patients with underlying mood disorders (Geriatric Anxiety and Depression Scales).33,34 An exercise-focused physical examination allows the physician to identify conditions that may impact exercise in the elderly but also can be used to track the beneficial changes of an exercise program.
Functional assessment
A thorough functional assessment, including gait analysis, is indicated in all older adults considering beginning an exercise program and who are actively exercising. Evaluation of fall risk and discussion of safe activities should take place prior to any exercise program or new athletic activity for the regularly exercising older adult. For this reason, objective measurement tools (e.g., Timed Up and Go Test, Duke Activity Status Index,35 Physical Activity Scale for the Elderly33,34) are helpful in determining actual baseline energy expenditure. Additionally, these tools can give insight into the patient’s ability to perform functional activities. Discussion of patient’s independence levels during Activities of Daily Living (ADLs) and Instrumental Activities of Daily Living (IADLs) can be used to determine the patient’s physical functional level. Counseling based on objective assessment will be better received and likely have more utility in independent and potentially overconfident geriatric exercisers.
Laboratory Studies
There are no routine laboratory studies that are recommended in older adults prior to initiating a new exercise program. The use of routine electrocardiogram is not indicated either. According to the guidelines set forth by the American College of Sports Medicine in 2018, older adults who do not engage in regular exercise but would like to and do not have any signs or symptoms and current cardiovascular, renal or metabolic diseases may engage physical activity without medical clearance. Older adults who show signs of or have known cardiovascular, renal or metabolic disease are recommended to obtain medical clearance.3
Supplemental assessment tools
Exercise and Physical Activity Tracking Tool worksheets are simple ways for older patients to track exercise and activity levels with samples available online on the National Institute of Aging website.36 Pedometers are low cost tools that track the number of steps a person takes during a day and can classify an older adult as highly active (more than 10 000 steps/day), moderately active (less than 10 000 steps/day but more than 5 000 steps/day) or inactive (less than 5 000 steps/day).22,37,38 Data for two to three days in an older adult reflects the usual daily physical activity of an individual.22 Accelerometers provide information about exercise frequency, intensity and duration of various movements in a given day.22 New technological devices such as smart watches have these tools integrated with heart rate monitors that allow individuals to track activity levels in a live format.
Environmental
Proper footwear and clothing are recommended for older adults during physical activity which should match the exercise type that is performed.39 Walking is the preferred mode of physical activity in older adults and options such as mall-walking or indoor gym facilities may facilitate participation in older adults. Environmental factors such as hills, stairs, uneven walking surfaces and weather have been identified as barriers to exercise.40 Generally, access to parks, recreational facilities, safe footpaths and areas free from crime have been known to influence physical activity levels in all age exercisers.22 It is important to consider ambient temperature in exercise with older adults as there is an attenuated ability to dissipate heat with age thus subjecting older individuals to increased risk of heat-related illness during exercise in heat.41
Social role and social support system
Group exercise in the elderly provides an opportunity for social support for individuals as a lack of company was the second most cited reason for not exercising in older adults.42 Community-based group exercise programs increase physical activity levels and improve adherence rates in older adults. Those who join have an improved sense of well-being, quality of life and expanded social network.43 This has an impact on overall health as older adults with appropriate social relationships have a greater likelihood of survival compared to those with limited social support.43,44 Participating in regular group exercises increases social connectedness and a sense of security in the community through peer support.45 Community-based exercise programs, the Silver Sneakers, and Enhance Fitness are exercise programs designed for older adults that provide this opportunity and should be suggested when initiating an exercise regimen.
Rehabilitation Management and Treatments
See Exercise in the Elderly Part Two
Cutting Edge Concepts and Practice
See Exercise in the Elderly Part Two
Gaps in the Evidence-Based Knowledge
See Exercise in the Elderly Part Two
References
- Capersen CJ, Powell KE, Christenson GM. Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research. Public Health Rep. 1985;100(2):126‐131.
- Britannica, T. Editors of Encyclopaedia (2023, January 26). old age. Encyclopedia Britannica. https://www.britannica.com/science/old-age
- Riebe D, Ehrman JK, Liguori G, Magal M. American College of Sports Medicine’s guidelines for exercise testing and prescription. 10th ed. Philadelphia, PA.Wolters Kluwer; 2018.
- Jackson, A. S., Beard, E. F., Wier, L. T., Ross, R. M., Stuteville, J. E., & Blair, S. N. (1995). Changes in aerobic power of men, ages 25-70 yr. Medicine and science in sports and exercise, 27(1), 113–120.
- Target Heart Rate and Estimated Maximum Heart Rate (2022, June 3). https://www.cdc.gov/physicalactivity/basics/measuring/heartrate.htm#:~:text=You%20can%20estimate%20your%20maximum,beats%20per%20minute%20(bpm).
- Prince M, Wimo A, Guerchet M, Ali G, Wu Y, Prina M. The global impact of dementia: an analysis of prevalence, incidence, cost and trends. World Alzheimer Report 2015. https://www.alz.co.uk/research/WorldAlzheimerReport2015.pdf. 2015. Accessed May 11, 2020.
- Mora JC, Valencia WM. Exercise and Older Adults. Clin Geriatr Med. 2018;34(1):145‐162.
- Watson KB, Carlson SA, Gunn JP, et al. Physical Inactivity Among Adults Aged 50 Years and Older – United States, 2014. MMWR Morb Mortal Wkly Rep. 2016;65(36):954‐958. Published 2016 Sep 16.
- American College of Sports Medicine, Chodzko-Zajko WJ, Proctor DN, et al. American College of Sports Medicine position stand. Exercise and physical activity for older adults. Med Sci Sports Exerc. 2009;41(7):1510‐1530.
- Siparsky PN, Kirkendall DT, Garrett WE Jr. Muscle changes in aging: understanding sarcopenia. Sports Health. 2014;6(1):36‐40.
- Kirkendall DT, Garrett WE Jr. The effects of aging and training on skeletal muscle. Am J Sports Med. 1998;26(4):598‐602.
- Concannon, L.G., Grierson, M.J. and Harrast, M.A. (2012), Exercise in the Older Adult: From the Sedentary Elderly to the Masters Athlete. PM&R, 4: 833-839. https://doi.org/10.1016/j.pmrj.2012.08.007
- Jakovljevic DG. Physical activity and cardiovascular aging: Physiological and molecular insights. Exp Gerontol. 2018;109:67‐74.
- Dani, M., Dirksen, A., Taraborrelli, P., Panagopolous, D., Torocastro, M., Sutton, R., & Lim, P. B. (2021). Orthostatic hypotension in older people: considerations, diagnosis and management. Clinical medicine (London, England), 21(3), e275–e282. https://doi.org/10.7861/clinmed.2020-1044
- Cifu, D. X., & Jaramillo, C. A. (2020). In Braddom’s physical medicine and Rehabilitation (sixth edition) (pp. 594–604). essay, Elsevier.
- Sharma, G., & Goodwin, J. (2006). Effect of aging on respiratory system physiology and immunology. Clinical interventions in aging, 1(3), 253–260. https://doi.org/10.2147/ciia.2006.1.3.253
- Terrier P, Reynard F. Effect of age on the variability and stability of gait: a cross‐sectional treadmill study in healthy individuals between 20 and 69 years of age. Gait Posture 2015;41(1):170–174.
- Osoba, M. Y., Rao, A. K., Agrawal, S. K., & Lalwani, A. K. (2019). Balance and gait in the elderly: A contemporary review. Laryngoscope investigative otolaryngology, 4(1), 143–153. https://doi.org/10.1002/lio2.252
- Verlinden VJA, van der Geest JN, Hoogendam YY, Hofman A, Breteler MMB, Ikram MA. Gait patterns in a community‐dwelling population aged 50 years and older. Gait Posture 2013;37(4):500–505.
- Burke TN, Franca FJ, Ferreira de Meneses SR, Cardoso VI, Marques AP. Postural control in elderly persons with osteoporosis: efficacy of an intervention program to improve balance and muscle strength: a randomized controlled trial.Am J Phys Med Rehabil. 2010;89(7):549-556.
- Galloza, J, Castillo B, Micheo W. Benefits of Exercise in the Older Population. Phys Med Rehabil Clin N Am. 2017;28(4):659-669.
- Taylor D. Physical activity is medicine for older adults. Postgraduate Medical Journal 2014;90:26-32.
- Cartee, G. D., Hepple, R. T., Bamman, M. M., & Zierath, J. R. (2016). Exercise Promotes Healthy Aging of Skeletal Muscle. Cell metabolism, 23(6), 1034–1047. https://doi.org/10.1016/j.cmet.2016.05.007
- Cruz-Jentoft, A. J., Bahat, G., Bauer, J., Boirie, Y., Bruyère, O., Cederholm, T., Cooper, C., Landi, F., Rolland, Y., Sayer, A. A., Schneider, S. M., Sieber, C. C., Topinkova, E., Vandewoude, M., Visser, M., Zamboni, M., & Writing Group for the European Working Group on Sarcopenia in Older People 2 (EWGSOP2), and the Extended Group for EWGSOP2 (2019). Sarcopenia: revised European consensus on definition and diagnosis. Age and ageing, 48(1), 16–31. https://doi.org/10.1093/ageing/afy169
- Hernández Morante JJ, Gómez Martínez C, Morillas-Ruiz JM. Dietary Factors Associated with Frailty in Old Adults: A Review of Nutritional Interventions to Prevent Frailty Development. Nutrients. 2019;11(1):102. Published 2019 Jan 5.
- Fried L.P., Tangen C.M., Walston J., et. al.: Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci 2001; 56: pp. M146-156.
- Cesari, M., Landi, F., Vellas, B., Bernabei, R., & Marzetti, E. (2014). Sarcopenia and physical frailty: two sides of the same coin. Frontiers in aging neuroscience, 6, 192. https://doi.org/10.3389/fnagi.2014.00192
- Liu CK, Fielding RA. Exercise as an intervention for frailty. Clin Geriatr Med. 2011;27(1):101‐110.
- Kallinen M, Markku A. Aging, physical activity and sports injuries. An overview of common sports injuries in the elderly. Sports Med. 1995;20(1):41‐52.
- Yoshimura, Y., Matsumoto, A., & Momosaki, R. (2022). Pharmacotherapy and the Role of Pharmacists in Rehabilitation Medicine. Progress in rehabilitation medicine, 7, 20220025. https://doi.org/10.2490/prm.20220025
- Clarke CL, Witham MD. The Effects of Medication on Activity and Rehabilitation of Older People – Opportunities and Risks. Rehabilitation Process and Outcome. 2017;6. doi:10.1177/1179572717711433
- Nied RJ, Franklin B. Promoting and prescribing exercise for the elderly. Am Fam Physician. 2002;65(3):419‐426.
- Segal DL, June A, Payne M, Coolidge FL, Yochim B. Development and Initial validation of self-report assessment tool for anxiety among older adults: the Geriatric Anxiety Scale. J Anxiety Disord. 2010 Oct;24(7): 709-714.
- Marc LG, Raue PJ, Bruce ML. Screening performance of the 15-item geriatric depression scale in a diverse elderly home care population. Am J Geriatr Psychiatry. 2008;16(11):914‐921. doi:10.1097/JGP.0b013e318186bd67.
- Hlatky MA, Boineau RE, Higginbotham MB, et al. A brief self-administered questionnaire to determine functional capacity the Duke Activity Status Index.Am J Cardiol. 1989;64(10):651-654.
- National Institute of Aging. Exercise and Physical Activity Tracking Tools. https://www.nia.nih.gov/health/exercise-and-physical-activity-tracking-tools. Updated April 3 2020. Accessed May 11 2020.
- Cavanaugh JT, Kochi N, Stergiou N. Nonlinear analysis of ambulatory activity patterns in community-dwelling older adults. J Gerontol A Biol Med Sci. 2010 Feb;65(2):197-203.
- Cavanaugh JT, Coleman KL, Gaines JM, Laing L, Morey MC. Using step activity monitoring to characterize ambulatory activity in community-dwelling older adults. J Am Geriatri Soc. 2007 Jan;55(2): 120-124.
- National Institute of Aging. Finding the Right Fitness Shoes and Clothes. https://www.nia.nih.gov/health/finding-right-fitness-shoes-and-clothes. Updated April 2 2020. Accessed May 12 2020.
- Bethancourt HJ, Rosenberg DE, Beatty T, Arterburn DE. Barriers to and facilitators of physical activity program use among older adults. Clin Med Res. 2014;12(1-2):10‐20. doi:10.3121/cmr.2013.1171.
- Balmain BN, Sabapathy S, Louis M, Morris NR. Aging and Thermoregulatory Control: The Clinical Implications of Exercising under Heat Stress in Older Individuals. Biomed Res Int. 2018;2018:8306154. Published 2018 Aug 2. doi:10.1155/2018/8306154.
- Moschny A, Platen P, Klaaben-Mielke R. et al. Barriers to physical activity in older adults in Germany: a cross-sectional study. Int J Behav Nutr Phys Act 8, 121 (2011). https://doi.org/10.1186/1479-5868-8-121.
- Holt-Lunstad J, Smith TB, Layton JB. Social relationships and mortality risk: a meta-analytic review. PLoS Med. 2010;7:e1000316.
- Killingback C, Tsofliou F, Clark C. Older people’s adherence to community-based group exercise programmes: a multiple-case study. BMC Public Health. 2017;17(1):115. doi:10.1186/s12889-017-4049-6.
- Komatsu, H., Yagasaki, K., Saito, Y. et al. Regular group exercise contributes to balanced health in older adults in Japan: a qualitative study. BMC Geriatr 17, 190 (2017). https://doi.org/10.1186/s12877-017-0584-3.
Original Version on the Topic
David Z. Prince, MD. Exercise in the elderly. 9/20/2014
Previous Revision(s) on the Topic
Joe Mendez, MD, Melissa Mafiah, MD, Alexandre Mazar, MD. Exercise in the elderly. 8/20/2020
Author Disclosures
Johnathan K Ho, MD
Nothing to Disclose
Darryl Chow, MD
Nothing to Disclose