Numerous studies have demonstrated an association between a lifestyle, including frequent moderate to vigorous physical activity and a reduced incidence of CHD. The benefits of exercise have been documented in both men and women, and can exceed a 50% lower risk of CHD. In this study, despite the relationships between predominately sports-related physical activity and a less atherogenic cardiovascular risk factor profile, physical activity was unrelated to the presence and extent of calcified subclinical atherosclerosis.
Part of the reduction in CHD risk associated with exercise is produced by favorable effects on cardiovascular risk factors. This can be summarized as a favorable effect on the insulin-resistant phenotype, including the specific components of obesity (2,9,14,19), blood pressure (2,17,19,30), fibrinogen (15,17), HDL cholesterol (2,9,14,19,30), small dense LDL cholesterol (9), diabetes mellitus, and insulin resistance (14,30). Our data confirms these benefits within a relatively healthy, middle-aged population, including reductions in blood pressure, fibrinogen, serum insulin levels, obesity, and increased HDL cholesterol.
Despite the favorable associations between physical activity and risk factors that promote the development of coronary atherosclerosis, we did not find a relationship between physical activity and the presence or extent of calcified subclinical atherosclerosis. This is in direct contrast to prior cross-sectional studies demonstrating that physical activity is associated with prevalent, subclinical CHD (30), to angiographic coronary artery disease, and to the extent (8) and progression of noncalcified atherosclerosis detected in the common carotid artery. Furthermore, a high level of leisure time physical activity has been shown to delay coronary atherosclerosis progression (10).
Prior studies have established that coronary artery calcification, a validated surrogate for the presence and extent of coronary atherosclerosis (25), is related to multiple cardiovascular risk factors (32). In particular, LDL cholesterol is one of the most important variables related to the presence (29) and progression (5,26) of coronary calcium. In contrast, a relationship between LDL cholesterol and physical activity has not been consistently demonstrated by these observational and cross-sectional studies (2,9) or in randomized trials (33). This suggests that exercise may exert a differential effect on the presence and extent of calcified versus noncalcified atherosclerosis, in part mediated through its limited effect on LDL cholesterol.
This study assessed physical activity and coronary calcification in a cross-sectional manner. Longitudinal data are needed to definitively exclude an effect of physical activity on calcified atherosclerosis. However, individuals tend to maintain relatively stable exercise habits (31), and the Baecke questionnaire has demonstrated reproducibility over time (23).
Obesity and diabetes mellitus are growing problems within the spectrum of coronary disease risk. Physical activity has a strong, inverse correlation with body mass index (2,9,14,19) and insulin resistance (14,30). Thus, the promotion of regular physical exercise achieves greater importance to lower the cardiovascular risk attributed to these risk factors. Our data from a middle-aged, relatively active cohort confirm these correlations and suggest caution is required when using anatomic screening tests acting as a “litmus test” in the evaluation and treatment of coronary risk factors. EBCT is a controversial test promulgated on its ability to detect patients at risk for CHD and to motivate behavioral change. However, because of the absence of a relationship between coronary calcification and physical activity, physical activity is an important cardiovascular risk variable that should not be overlooked in a patient with low, age-adjusted levels of coronary calcium. Sedentary lifestyle patterns should be discouraged in light of clear relationships seen in this and other studies between physical inactivity, obesity, insulin resistance, and CHD risk (8).
Physical activity, particularly high-intensity exercise in sports-related activities, promotes a healthy cardiovascular risk profile, including lower body mass index and insulin resistance but is unrelated to coronary calcification. This suggests that the risk reduction associated with physical activity is mediated by factors other than retarding the development of calcified atherosclerosis. Simple clinical advice for adherence to AHA recommendations for physical activity is prudent for the maintenance of ideal body weight and an optimal cardiovascular risk factor profile, although it may not affect calcified atherosclerosis.
This study was funded by Walter Reed Army Medical Center.
This work was presented in part at the 50th Scientific Session of the American College of Cardiology, Orlando FL, March 2001.
The opinions or assertions herein are the private views of the authors and are not to be construed as reflecting the views of the Department of the Army or the Department of Defense.
Conflict of interest: None of the authors of this manuscript has a financial interest in this work. The results of this study do not constitute endorsement of any product by the authors or ACSM.
Address for correspondence: Allen J. Taylor, M.D., LTC MC USA, Director, Cardiovascular Research, Cardiology Service, Walter Reed Army Medical Center, 6900 Georgia Ave., NW, Building 2, Room 4A, Washington DC, 20307-5001; E-mail: firstname.lastname@example.org.
1. Agatston, A. S., W. R. Janowitz, F. J. Hildner, N. R. Zusmer, M. J. Viamonte, and R. Detrano. Quantification of coronary artery calcium using ultrafast computed tomography. J. Am. Coll. Cardiol. 15: 827–832, 1990.
2. Ashton, W. D., K. Nanchahal, and D. A. Wood. Leisure-time physical activity and coronary risk factors in women. J. Cardiovasc. Risk 7: 259–266, 2000.
3. Baecke, J. A., J. Burema, and J. E. Frijters. A short questionnaire for the measurement of habitual physical activity in epidemiological studies. Am. J. Clin. Nutr. 36: 936–942, 1982.
4. Burke, A. P., F. D. Kolodgie, A. FARB, et al. Healed plaque ruptures and sudden coronary death: evidence that subclinical rupture has a role in plaque progression. Circulation 103: 934–940, 2001.
5. Callister, T. Q., P. Raggi, B. Cooil, N. J. Lippolis, and D. J. Russo. Effect of HMG-CoA reductase inhibitors on coronary artery disease as assessed by electron beam. N. Engl. J. Med. 339: 1972–1978, 1998.
6. Canon, F., B. Levol, and F. Duforez. Assessment of physical activity in daily life. J. Cardiovasc. Pharmacol. 25 (Suppl. 1): S28–S34, 1995.
7. Folsom, A. R., D. K. Arnett, R. G. Hutchinson, F. Liao, L. X. Clegg, and L. S. Cooper. Physical activity and incidence of coronary heart disease in middle-aged women and men. Med. Sci. Sports Exerc. 29: 901–909, 1997.
8. Folsom, A. R., J. H. Eckfeldt, S. Weitzman, et al. Relation of carotid artery wall thickness to diabetes mellitus, fasting glucose and insulin, body size, and physical activity: Atherosclerosis Risk in Communities (ARIC) Study Investigators. Stroke 25: 66–73, 1994.
9. Halle, M., A. Berg, M. W. Baumstark, and J. Keul. Association of physical fitness with LDL and HDL subfractions in young healthy men. Int. J. Sports Med. 20: 464–469, 1999.
10. Hambrecht, R., J. Niebauer, C. Marburger, et al. Various intensities of leisure time physical activity in patients with coronary artery disease: effects on cardiorespiratory fitness and progression of coronary atherosclerotic lesions. J. Am. Coll. Cardiol. 22: 468–477, 1993.
11. Hambrecht, R., A. Wolf, S. Gielen, et al. Effect of exercise on coronary endothelial function in patients with coronary artery disease. N. Engl. J. Med. 342: 454–460, 2000.
12. Kaufman, D. W., J. R. Palmer, L. Rosenberg, and S. Shapiro. Cigar and pipe smoking and myocardial infarction in young men. Br. Med. J. (Clin. Res. Ed.) 294: 1315–1316, 1987.
13. Lakka, T. A., J. A. Laukkanen, R. Rauramaa, et al. Cardiorespiratory fitness and the progression of carotid atherosclerosis in middle-aged men. Ann. Intern. Med. 134: 12–20, 2001.
14. Lakka, T. A., and J. T. Salonen. Physical activity and serum lipids: a cross-sectional population study in eastern Finnish men. Am. J. Epidemiol. 136: 806–818, 1992.
15. Lakka, T. A., and J. T. Salonen. Moderate to high intensity conditioning leisure time physical activity and high cardiorespiratory fitness are associated with reduced plasma fibrinogen in eastern Finnish men. J. Clin. Epidemiol. 46: 1119–1127, 1993.
16. Lakka, T. A., J. M. Venalainen, R. Rauramaa, R. Salonen, J. Tuomilehto, and J. T. Salonen. Relation of leisure-time physical activity and cardiorespiratory fitness to the risk of acute myocardial infarction. N. Engl. J. Med. 330: 1549–1554, 1994.
17. Lee, I. M., H. D. Sesso, and R. S. Paffenbarger, Jr. Physical activity and coronary heart disease risk in men: does the duration of exercise episodes predict risk? Circulation 102: 981–986, 2000.
18. Mensink, G. B., M. Deketh, M. D. Mul, A. J. Schuit, and H. Hoffmeister. Physical activity and its association with cardiovascular risk factors and mortality. Epidemiology 7: 391–397, 1996.
19. Mensink, G. B., D. W. Heerstrass, S. E. Neppelenbroek, A. J. Schuit, and B. M. Bellach. Intensity, duration, and frequency of physical activity and coronary risk factors. Med. Sci. Sports Exerc. 29: 1192–1198, 1997.
20. Mintz, G. S., A. D. Pichard, J. J. Popma, et al. Determinants and correlates of target lesion calcium in coronary artery disease: a clinical, angiographic and intravascular ultrasound study. J. Am. Coll. Cardiol. 29: 268–274, 1997.
21. O’Malley, P. G., A. J. Taylor, R. V. Gibbons, et al. Rationale and design of the Prospective Army Coronary Calcium (PACC) Study: utility of electron beam computed tomography as a screening test for coronary artery disease and as an intervention for risk factor modification among young, asymptomatic, active-duty United States Army personnel. Am. Heart J. 137: 932–941, 1999.
22. O’Malley, P. G., A. J. Taylor, J. L. Jackson, T. M. Doherty, and R. C. Detrano. Prognostic value of coronary electron-beam computed tomography for coronary heart disease events in asymptomatic populations. Am. J. Cardiol. 85: 945–948, 2000.
23. Pols, M. A., P. H. Peeters, H. B. Bueno-De-Mesquita, et al. Validity and repeatability of a modified Baecke questionnaire on physical activity. Int. J. Epidemiol. 24: 381–388, 1995.
24. Richardson, M. T., B. E. Ainsworth, H. C. Wu, D. R. Jacobs, Jr., and A. S. Leon. Ability of the Atherosclerosis Risk in Communities (ARIC)/Baecke Questionnaire to assess leisure-time physical activity. Int. J. Epidemiol. 24: 685–693, 1995.
25. Sangiorgi, G., J. A. Rumberger, A. Severson, et al. Arterial calcification and not lumen stenosis is highly correlated with atherosclerotic plaque burden in humans: a histologic study of 723 coronary artery segments using nondecalcifying methodology. J. Am. Coll. Cardiol. 31: 126–133, 1998.
26. Schmermund, A., D. Baumgart, S. Mohlenkamp, et al. Natural history and topographic pattern of progression of coronary calcification in symptomatic patients: an electron-beam CT study. Arterioscler. Thromb. Vasc. Biol. 21: 421–426, 2001.
27. Sesso, H. D., R. S. Paffenbarger, Jr., and I. M. Lee. Physical activity and coronary heart disease in men: the Harvard Alumni Health Study. Circulation 102: 975–980, 2000.
28. Slattery, M. L., D. R. Jacobs, Jr., and M. Z. Nichaman. Leisure time physical activity and coronary heart disease death: the US Railroad Study. Circulation 79: 304–311, 1989.
29. Taylor, A. J., I. M. Feuerstein, H. Wong, W. Barko, M. Brazaitis, and P. G. O’Malley. Do conventional risk factors predict subclinical coronary artery disease? Results from the Prospective Army Coronary Calcium Project. Am. Heart J. 141: 463–468, 2001.
30. Wannamethee, S. G., A. G. Shaper, and M. Walker. Changes in physical activity, mortality, and incidence of coronary heart disease in older men. Lancet 351: 1603–1608, 1998.
31. Wannamethee, S. G., A. G. Shaper, and K. G. Alberti. Physical activity, metabolic factors, and the incidence of coronary heart disease and type 2 d, and the incidence of coronary heart disease and type 2 diabetes. Arch. Intern. Med. 160: 2108–2116, 2000.
32. Wong, N. D., D. Kouwabunpat, A. N. Vo, et al. Coronary calcium and atherosclerosis by ultrafast computed tomography in asymptomatic men and women: relation to age and risk factors. Am. Heart J. 127: 422–430, 1994.
33. Wood, P. D., M. L. Stefanick, D. M. Dreon, et al. Changes in plasma lipids and lipoproteins in overweight men during weight loss through dieting as compared with exercise. N. Engl. J. Med. 319: 1173–1179, 1988.