Keith Diaz, PhD

Profile Headshot


Academic Appointments

  • Assistant Professor of Behavioral Medicine (in Medicine and Psychiatry)

Credentials & Experience

Education & Training

  • BS, 2006 Exercise Physiology, William Paterson University
  • PhD, 2012 Integrative Exercise Physiology, Temple University


Keith Diaz, PhD is a certified exercise physiologist and Assistant Professor of Behavioral Medicine at Columbia University Medical Center. He is Director of the Exercise Testing Laboratory at the Center for Behavioral Cardiovascular Health. He conducts laboratory- and observational-based research to elucidate the role of prolonged sedentary behavior in the pathogenesis of cardiovascular disease, with a specific focus of iteratively optimizing feasible, sustainable, and cost-effective guidelines for reducing prolonged sitting. He is currently PI of a prospective cohort study examining objectively-measured sedentary behavior as a risk factor for recurrent cardiovascular outcomes in coronary heart disease patients. He is also PI of laboratory-based, cross-over trial examining the optimal frequency and duration of sedentary breaks for improving cardiometabolic health. Dr. Diaz is also interested in the objective measurement of physical activity and sedentary behavior via accelerometry. He has conducted laboratory-based studies testing the validity and reliability of wireless physical activity monitors including the Fitbit One and Fitbit Flex. Dr. Diaz’s past work has involved studying the effects of aerobic exercise training on endothelial health in sedentary African Americans. Findings from this work included the observation that aerobic exercise training elicited robust reductions in circulating endothelial microparticles; the first study to demonstrate a favorable effect of a lifestyle intervention on circulating endothelial microparticles. His work has been featured by the New York Times, CNN, CBS News, NPR,and the Guardian, among many others.

Research Interests

  • Accelerometry
  • Cardiovascular Biomarkers
  • Physical Activity
  • Sedentary Behavior

Selected Publications

  • Garcia J, Duran AT, Schwartz JE, Booth JN, Hooker SP, Willey JZ, Cheung YK, Park C, Williams SK, Sims M, Shimbo D, Diaz KM. Types of Sedentary Behavior and Risk of Cardiovascular Events and Mortality in African-Americans: The Jackson Heart Study. J Am Heart Assoc. 2019;8:e010406. PMID: 31238767

  • Diaz KM, Duran AT, Colabianchi N, Judd SE, Howard VJ, Hooker SP. Potential Effects of Replacing Sedentary Time with Short Sedentary Bouts or Physical Activity on Mortality: A National Cohort Study. Am J Epidemiol. 2019;188:537-544. PMID: 30551177

  • Diaz KM, Thanataveerat A, Parsons FE, Yoon S, Cheung YK, Alcantara C, Duran AT, Ensari I, Krupka DJ, Schwartz JE, Burg MM, Davidson KW. The Influence of Daily Stress on Sedentary Behavior: Group and Person (N of 1) Level Results of a 1-Year Observational Study. Psychosom Med. 2018;80(7):620-627. PMID: 29846309

  • Yoon S, Schwartz JE, Burg MM, Kronish IM, Alcantara C, Julian J, Parsons F, Davidson KW, Diaz KM. Using behavioral analytics to increase exercise: a randomized N-of-1 study. Am J Prev Med. 2018;54(4):559-567. PMCID: PMC5860951

  • Diaz KM, Howard V, Hutto B, Colabianchi N, Vena JE, Safford MM, Blair SN, Hooker SP. Patterns of sedentary behavior and mortality in U.S. middle-aged and older adults: A national cohort study. Ann Intern Med. 2017;167(7):465-475. PMCID: PMC5961729
  • Diaz KM, Goldsmith J, Greenlee H, Strizich G, Qi Q, Mossavar-Rahmani Y, Vidot DC, Buelna C, Brintz CE, Elfassy T, Gallo LC, Daviglus ML, Sotres-Alvarez D, Kaplan R. Prolonged, uninterrupted sedentary behavior and glycemic biomarkers among US Hispanic/Latino adults: The Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Circulation. 2017;136(15):1362-1373. PMCID: PMC5634934
  • Kronish IM, Diaz KM, Goldsmith J, Moise N, Schwartz JE. Objectively measured adherence to physical activity guidelines after acute coronary syndrome. J Am Coll Cardiol. 2017; 69(9):1205-1207. PMCID: PMC5522177
  • Diaz KM, Booth JN 3rd, Seals SR, Abdalla M, Dubbert PM, Sims M, Ladapo JA, Redmond N, Muntner P, Shimbo D. Physical activity and incident hypertension in African Americans: the Jackson Heart Study. Hypertension. 2017; 69(3):421-427. PMCID: PMC5302780
  • Diaz KM, Booth JN 3rd, Seals SR, Hooker SP, Sims M, Dubbert PM, Muntner P, Shimbo D. Sedentary Behavior and Subclinical Atherosclerosis in African Americans: Cross-sectional Analysis of the Jackson Heart Study. Int J Behav Nutr Phys Act. 2016;13(1):31. PMCID: PMC4772318
  • Diaz KM, Howard VJ, Hutto B, Colabianchi N, Vena JE, Blair SN, Hooker SP. Patterns of sedentary behavior in US middle-aged and older adults: the REGARDS study. Med Sci Sports Exerc. 2016;48(3):430-438. PMCID: PMC4760895
  • Diaz KM, Krupka DJ, Chang MJ, Peacock J, Ma Y, Goldsmith J, Schwartz JE, Davidson KW. Fitbit: An accurate and reliable device for wireless physical activity tracking. Int J Cardiol. 2015;185:138-140. PMCID: PMC4406840
  • Diaz KM, Booth JN III, Calhoun DA, Irvin MR, Howard G, Safford MM, Muntner P, Shimbo D. Healthy lifestyle factors and risk of cardiovascular events and mortality in treatment-resistant hypertension: the Reasons for Geographic and Racial Differences in Stroke study. Hypertension. 2014;64(3):465-471. PMCID: PMC4134352