Athlete’s Heart: Why Bigger is Not Always Better, or Worse

Alberto Contador Velasco is a Spanish former professional cyclist. He is one of the most successful riders of his era, winning the Tour de France twice, the Giro d’Italia twice, and the Vuelta a España three times.

What doesn’t kill you does not always make you stronger.

But it doesn’t necessarily make you weaker, either.

At least when it comes to exercise and your heart.

Most data indicates that in the short-term, exercise doesn’t cause heart damage, even if it makes your heart a little tired.

However, this doesn’t tell us how it affects your heart in the long-term.

In this article, we’ll look at one of the last stages of the cardiotoxicity cycle — how exercise changes your heart over time, and how these changes affect your health.

How Exercise Changes Your Heart

During exercise, your cardiovascular system has to pump more blood to supply your working muscles.

With enough training, this increased demand for blood changes the shape, size, and function of your heart and blood vessels — a condition called “athlete’s heart syndrome.”

Genetics, gender, age, body size, and other factors also determine your heart size, but exercise is the main one.(1)

There are four main features of athlete’s heart:(2-20)

  1. Increased mass, thickness, and volume.
  2. Changes in filling rate, elasticity, and compliance.
  3. Increased blood vessel width, capillarization, elasticity, and blood volume.
  4. Altered electrical activity, heart rate, and heart rate variability.

The four main features of athlete’s heart.

 

It would probably be more accurate to call this “athlete’s cardiovascular system,” since it also affects the blood vessels and nervous system, but “athlete’s heart” is easier to say.

This is a huge topic, so we’ll focus on the structural changes of athlete’s heart in this article. We’ll look at how exercise changes the electrical activity of the heart later.

The Anatomy of an Athlete’s Heart

Every sport changes your heart in slightly different ways, depending on the demands.(21-24)

Endurance sports like running and cycling tend to produce eccentric hypertrophy (growth). The walls of the heart become thicker, and the chambers become wider to allow more blood inside.

On the other hand, strength and power sports like weight lifting and sprinting tend to increase the thickness of the heart walls, rather than their volume. Researchers call this concentric hypertrophy.

Sports that require both strength and endurance like swimming, rowing, and triathlon tend to produce changes somewhere in the middle.

There are some caveats to this, as heart size is also largely determined by how much you train.(25,26) Elite cyclists, rowers, and swimmers, who train more than most power athletes, can actually develop thicker hearts than weight lifters, despite being more endurance focused.(27)

Any athlete that participates in a demanding sport is likely to develop some changes in heart size. These changes can start to worry doctors if they become too great.

Is Your Heart in the “Gray Zone?”

Athlete’s heart is a spectrum.

It ranges from small, almost insignificant changes to extreme abnormalities.

In the latter cases, it’s often hard to tell the difference between athlete’s heart and heart disease, or if there is a difference.(28-29) This is especially true for endurance sports which tend to produce the largest changes, yet bodybuilders, throwers, and Olympic and power lifters can also develop enlarged hearts.

These extreme cases of athlete’s heart are in what researchers call the “gray zone” — a range somewhere between normal and abnormal.(30)

In some cases, exercise can increase the size of the heart enough to make it appear similar to heart disease. These cases of athlete’s heart are in the “gray zone.”

 

Most recreational athletes have hearts that are within the normal, safe range of healthy people.(32-35)

There is a small increase in heart size after almost any training.(36-38) This effect starts after you go past about three hours of exercise per week and stops soon after.(39-40) It takes a lot of intense training to make the heart much larger.(41-46)

In fact, only about 50% of trained athletes develop significant changes in heart size.(47-49)

Among elite endurance athletes, about 15% develop changes large enough to get close to what might be considered a sign of disease — the gray zone.(50

Most athletes don’t get close to the gray zone, but when they do, some authors believe this might be dangerous.(51-55)

Why an Enlarged Heart Might be Dangerous

Most of the time, heart enlargement (cardiac hypertrophy) is caused by heart disease.(56-58)

People with enlarged hearts have a higher risk of coronary artery disease, cerebrovascular disease, dangerous arrhythmias, cardiac failure, sudden cardiac death, and an early death from all causes.(59-66)

Studies have also shown that athlete’s with larger hearts and more training sometimes have higher levels of atherosclerosis and heart damage.(67-71)

Despite these concerns, most data indicates that athlete’s heart is safe for the majority of athletes, and may have some benefits.

Why Athlete’s Heart is Probably Not Dangerous for Most Athletes

Athlete’s heart and heart disease are both compensatory mechanisms, but with different causes.

Heart enlargement caused by heart disease is usually caused by either a genetic condition called hypertrophic cardiomyopathy (HCM) or hypertension.

It’s not clear what causes the heart to grow in HCM. In hypertensive heart disease, the heart grows larger as a way to manage the chronic increase in blood pressure. This works for a little while, but the heart often fails.(72)

Athlete’s heart is also caused by increased pressure and expansion, but it’s intermittent as opposed to chronic. The heart grows thicker, wider, and stronger to better pump blood to the working muscles.(73,74)

After a workout your heart is fatigued from the effort, and but it has time to recover and adapt, in contrast to chronic hypertension. There’s also little evidence that your heart is damaged after even the most brutal workouts.

Dr. Aaron Baggish, the author of a recent review on this topic, believes athlete’s heart is a “beneficial physiologic adaptation” to exercise.(75,76) This is opposed to a pathological adaptation, as in heart disease.

Most data suggests that athlete’s heart and heart disease are two distinct conditions, and “most authors… believe that athletic left ventricular hypertrophy [heart enlargement] is a purely physiological [safe] condition.”(77,78)

The idea that athlete’s heart is a sign of heart disease “has resurfaced numerous times over the last 110 years of scientific inquiry despite the fact that there is no clear evidence to substantiate its validity,” continues Dr. Baggish.

This doesn’t mean that athlete’s heart is completely safe, but “there is no evidence at present showing that athlete’s heart remodeling leads to long-term disease progression, cardiovascular disability, or sudden cardiac death,” writes Dr. Barry Maron, the author of another excellent review on athlete’s heart.(79)

Nevertheless, the idea that extreme athlete’s heart could be harmful in some cases “is perhaps unlikely but at this time cannot be excluded with certainty.”

There’s also little evidence that having an enlarged heart is going to make you much healthier. It’s unlikely that a marathon runner is going to have a healthier heart than someone who lifts weights a few times a week and stays active with other light activity.

In the end, there’s not much evidence having a large, athlete’s heart is bad or good for you.

In the next few articles, we’ll look at the main reasons why most researchers believe that athlete’s heart is safe, and the evidence it may be harmful. We’ll also look at ways to make sure your training does not damage your heart.

These articles are not meant to prove or disprove whether or not athlete’s heart is safe. The goal is to provide a clear view of the current evidence so you can make an informed decision about your exercise levels.

You’re reading Part 6 of a series on whether or not exercise damages your heart. Click here to read Part 7.

You can read the first post in this series by clicking here.

 

References

1. Maron BJ, Pelliccia A. The heart of trained athletes: cardiac remodeling and the risks of sports, including sudden death. Circulation. 2006 Oct 10;114(15):1633-44. Abstract: https://pmid.us/17030703 | Full Text: https://goo.gl/qirCb | Author Contact: <hcm.maron@mhif.org>

2. Maron BJ, Pelliccia A. The heart of trained athletes: cardiac remodeling and the risks of sports, including sudden death. Circulation. 2006 Oct 10;114(15):1633-44. Abstract: https://pmid.us/17030703 | Full Text: https://goo.gl/qirCb | Author Contact: <hcm.maron@mhif.org>

3. Baggish AL, Wood MJ. Athlete’s heart and cardiovascular care of the athlete: scientific and clinical update. Circulation. 2011 Jun 14;123(23):2723-35. Abstract: https://pmid.us/21670241 | Full Text: https://goo.gl/fWiEj

4. Prior DL, La Gerche A. The athlete’s heart. Heart. 2012 Jun;98(12):947-55. doi: 10.1136/heartjnl-2011-301329. Abstract: https://pmid.us/22626903 | Full Text: Received from author.

5. La Gerche A, Taylor AJ, Prior DL. Athlete’s heart: the potential for multimodality imaging to address the critical remaining questions. JACC Cardiovasc Imaging. 2009 Mar;2(3):350-63. Abstract: https://pmid.us/19356581 | Full Text: https://goo.gl/K6iT2

6. George K, Spence A, Naylor LH, et al. Cardiac adaptation to acute and chronic participation in endurance sports. Heart. 2011 Dec;97(24):1999-2004. Epub 2011 Nov 5. Abstract: https://pmid.us/22058283 | Full Text: Received from author. | Author Contact: <K.George@ljmu.ac.uk>

7. Green DJ, Naylor LH, George K. Cardiac and vascular adaptations to exercise. Curr Opin Clin Nutr Metab Care. 2006 Nov;9(6):677-84. Abstract: https://pmid.us/17053419  | Full Text: https://goo.gl/hj036

8. Bhella PS, Levine BD. The Heart of a Champion. J Am Coll Cardiol. 2010;55(15):1626-1628. doi:10.1016/j.jacc.2009.12.030. Abstract: https://pmid.us/20378082 Full Text: https://goo.gl/TYG6W

9. Green DJ, Spence A, Rowley N, et al. Vascular adaptation in athletes: is there an ‘athlete’s artery’? Exp Physiol. 2012 Mar;97(3):295-304. Epub 2011 Dec 16. Abstract: https://pmid.us/22179421 | Full Text: NA

10. Green DJ, Spence A, Halliwill JR, et al. Exercise and vascular adaptation in asymptomatic humans. Exp Physiol. 2011 Feb;96(2):57-70. Epub 2010 Oct 22. Abstract: https://pmid.us/20971800 | Full Text: https://goo.gl/IJsvk

11. Fagard R. Athlete’s heart. Heart. 2003; 89: 1455–1461. Full Text: https://goo.gl/fAcqm

12. Oakley D. The athlete’s heart. Heart. 2001 December; 86(6): 722–726. doi: 10.1136/heart.86.6.722. Full Text: https://goo.gl/IgQZn

13. Pluim BM, Zwinderman AH, Van der laarse A, et al. The athlete’s heart. A meta-analysis of cardiac structure and function. Circulation. 2000;101(3):336-44. Abstract: https://pmid.us/10645932 | Full Text: https://goo.gl/DUQMk

14. Indermühle A, Vogel R, Rutz T, et al. Myocardial contrast echocardiography for the distinction of hypertrophic cardiomyopathy from athlete’s heart and hypertensive heart disease. Swiss Med Wkly. 2009 Nov 28;139(47-48):691-8. Abstract: https://pmid.us/20047131 | Full Text: https://goo.gl/1u7Zq

15. Indermühle A, Vogel R, Meier P, et al. The relative myocardial blood volume differentiates between hypertensive heart disease and athlete’s heart in humans. Eur Heart J. 2006 Jul;27(13):1571-8. Epub 2006 May 22. Abstract: https://pmid.us/16717078 | Full Text: https://goo.gl/kij8G

16. Carter JB, Banister EW, Blaber AP. Effect of endurance exercise on autonomic control of heart rate. Sports Med. 2003;33(1):33-46. Abstract: http:/pmid.us/12477376 | Full Text: https://goo.gl/UYfs3

17. Aubert AE, Seps B, Beckers F. Heart rate variability in athletes. Sports Med. 2003;33(12):889-919. Abstract: https://pmid.us/12974657 | Full Text: https://goo.gl/7Dp9m

18. Spence AL, Carter HH, Murray CP, et al. MRI-derived Right Ventricular Adaptations to Endurance versus Resistance Training. Med Sci Sports Exerc. 2012 Oct 15. Abstract: https://pmid.us/23073215 | Full Text: NA

19. Sztajzel J, Jung M, Sievert K, et al. Cardiac autonomic profile in different sports disciplines during all-day activity. J Sports Med Phys Fitness. 2008 Dec;48(4):495-501. Abstract: https://pmid.us/18997654 | Full Text: NA

20. Spence AL, Naylor LH, Carter HH, et al. A prospective randomised longitudinal MRI study of left ventricular adaptation to endurance and resistance exercise training in humans. J Physiol. 2011 Nov 15;589(Pt 22):5443-52. doi: 10.1113/jphysiol.2011.217125. Epub 2011 Oct 3. Abstract: https://pmid.us/21969450 | Full Text: https://goo.gl/W1Otl

21. Pluim BM, Zwinderman AH, Van der laarse A, et al. The athlete’s heart. A meta-analysis of cardiac structure and function. Circulation. 2000;101(3):336-44. Abstract: https://pmid.us/10645932 | Full Text: https://goo.gl/DUQMk

22. Spence AL, Naylor LH, Carter HH, et al. A prospective randomised longitudinal MRI study of left ventricular adaptation to endurance and resistance exercise training in humans. J Physiol. 2011 Nov 15;589(Pt 22):5443-52. doi: 10.1113/jphysiol.2011.217125. Epub 2011 Oct 3. Abstract: https://pmid.us/21969450 | Full Text: https://goo.gl/W1Otl

23. Baggish AL, Wood MJ. Athlete’s heart and cardiovascular care of the athlete: scientific and clinical update. Circulation. 2011 Jun 14;123(23):2723-35. Abstract: https://pmid.us/21670241 | Full Text: https://goo.gl/fWiEj

24. Prior DL, La Gerche A. The athlete’s heart. Heart. 2012 Jun;98(12):947-55. doi: 10.1136/heartjnl-2011-301329. Abstract: https://pmid.us/22626903 | Full Text: Received from author.

25. Pelliccia A, Culasso F, Di Paolo FM, et al. Physiologic left ventricular cavity dilatation in elite athletes. Ann Intern Med. 1999 Jan 5;130(1):23-31. Abstract: https://pmid.us/9890846 | Full Text: NA

26. Naylor LH, George K, O’Driscoll G, et al. The athlete’s heart: a contemporary appraisal of the ‘Morganroth hypothesis’. Sports Med. 2008;38(1):69-90. Abstract: https://pmid.us/18081368 | Full Text: NA

27. Maron BJ, Pelliccia A. The heart of trained athletes: cardiac remodeling and the risks of sports, including sudden death. Circulation. 2006 Oct 10;114(15):1633-44. Abstract: https://pmid.us/17030703 | Full Text: https://goo.gl/qirCb | Author Contact: <hcm.maron@mhif.org>

28. Maron BJ. Distinguishing hypertrophic cardiomyopathy from athlete’s heart: a clinical problem of increasing magnitude and significance. Heart. 2005 November; 91(11): 1380–1382. Full Text: https://goo.gl/8vZYo

29. Waterhouse DF, Ismail TF, Prasad SK, et al. Imaging focal and interstitial fibrosis with cardiovascular magnetic resonance in athletes with left ventricular hypertrophy: implications for sporting participation. Br J Sports Med. 2012 Nov;46 Suppl 1:i69-77. Abstract: https://pmid.us/23097483 | Full Text: https://goo.gl/v5YT7

30. Maron BJ. Sudden death in young athletes. N Engl J Med. 2003; 349: 1064–1075. Abstract: https://pmid.us/12968091 | Full Text: https://goo.gl/Hr0oB

31. Hildick-Smith DJ, Shapiro LM. Echocardiographic differentiation of pathological and physiological left ventricular hypertrophy. Heart. 2001 Jun;85(6):615-9. Abstract: https://pmid/11359735 | Full Text: https://goo.gl/kr8wy

32. Maron BJ. Structural features of the athlete heart as defined by echocardiography. J Am Coll Cardiol. 1986;7(1):190-203. Abstract: https://pmid.us/2934463 | Full Text: Requested from author.

33. Maron BJ, Pelliccia A. The heart of trained athletes: cardiac remodeling and the risks of sports, including sudden death. Circulation. 2006 Oct 10;114(15):1633-44. Abstract: https://pmid.us/17030703 | Full Text: https://goo.gl/qirCb | Author Contact: <hcm.maron@mhif.org>

34. Baggish AL, Wood MJ. Athlete’s heart and cardiovascular care of the athlete: scientific and clinical update. Circulation. 2011 Jun 14;123(23):2723-35. Abstract: https://pmid.us/21670241 | Full Text: https://goo.gl/fWiEj

35. La Gerche A, Taylor AJ, Prior DL. Athlete’s heart: the potential for multimodality imaging to address the critical remaining questions. JACC Cardiovasc Imaging. 2009 Mar;2(3):350-63. Abstract: https://pmid.us/19356581 | Full Text: https://goo.gl/K6iT2

36. Green HJ, Jones LL, Painter DC. Effects of short-term training on cardiac function during prolonged exercise. Med Sci Sports Exerc. 1990 Aug;22(4):488-93. Abstract: https://pmid.us/2402209 | Full Text: NA

37. Goodman JM, Liu PP, Green HJ. Left ventricular adaptations following short-term endurance training. J Appl Physiol. 2005 Feb;98(2):454-60. Epub 2004 Sep 24. Abstract: https://pmid.us/15448118 | Full Text: https://goo.gl/ngFm3

38. D’Ascenzi F, Cameli M, Lisi M, et al. Left atrial remodelling in competitive adolescent soccer players. Int J Sports Med. 2012 Oct;33(10):795-801. Epub 2012 May 4. Abstract: https://pmid.us/22562745 | Full Text: NA

39. Fagard R. Athlete’s heart. Heart. 2003; 89: 1455–1461. Full Text: https://goo.gl/fAcqm

40. Ehsani AA, Hagberg JM, Hickson RC. Rapid changes in left ventricular dimensions and mass in response to physical conditioning. Am J Cardiol.1978; 42: 52–56. Abstract: https://pmid.us/677037 | Full Text: NA

41. D’Andrea A, Riegler L, Golia E, et al. Range of right heart measurements in top-level athletes: The training impact. Int J Cardiol. 2011 Jul 5. Abstract: https://pmid.us/21737163 | Full Text: NA

42. Fagard R, Aubert A, Lysens R, et al. Noninvasive assessment of seasonal variations in cardiac structure and function in cyclists. Circulation. 1983; 67: 896–901. Abstract: https://pmid.us/6825246 | Full Text: https://goo.gl/jUm0I

43. Maron BJ, Pelliccia A, Spataro A, et al. Reduction in left ventricular wall thickness after deconditioning in highly trained Olympic athletes. Br Heart J.1993; 69: 125–128. Abstract: https://pmid.us/8435237 | Full Text: https://goo.gl/oRZu7

44. Fagard R. Athlete’s heart. Heart. 2003; 89: 1455–1461. Full Text: https://goo.gl/fAcqm

45. La Gerche A, Taylor AJ, Prior DL. Athlete’s heart: the potential for multimodality imaging to address the critical remaining questions. JACC Cardiovasc Imaging. 2009 Mar;2(3):350-63. Abstract: https://pmid.us/19356581 | Full Text: https://goo.gl/K6iT2

46. Ehsani AA. Loss of cardiovascular adaptations after cessation of training. Cardiol Clin. 1992 May;10(2):257-66. Abstract: https://pmid.us/1576615 | Full Text: NA

47. Maron BJ. Structural features of the athlete heart as defined by echocardiography. J Am Coll Cardiol. 1986;7(1):190-203.  Abstract: https://pmid.us/2934463 Full Text: Requested.

48. Sharma, S. (2003) Athlete’s heart–effect of age, sex, ethnicity and sporting discipline. Experimental Physiology 88, 665-669. Abstract: https://pmid.us/12955167 | Full Text: Received from author.

49. Teske AJ, Prakken NH, De Boeck BW, et al. Echocardiographic tissue deformation imaging of right ventricular systolic function in endurance athletes. Eur Heart J. 2009 Apr;30(8):969-77. Epub 2009 Feb 24. Abstract: https://pmid.us/19240064 | Full Text: https://goo.gl/yQzFk

50. Pelliccia A, Culasso F, Di Paolo FM, et al. Physiologic left ventricular cavity dilatation in elite athletes. Ann Intern Med. 1999 Jan 5;130(1):23-31. Abstract: https://pmid.us/9890846 | Full Text: NA

51. Patil HR, O’keefe JH, Lavie CJ, et al. Cardiovascular damage resulting from chronic excessive endurance exercise. Mo Med. 2012 Jul-Aug;109(4):312-21. Abstract: https://pmid.us/22953596 | Full Text: https://goo.gl/pxtJj | Author Contact: <jokeefe@saint-lukes.org>

52. O’keefe JH, Patil HR, Lavie CJ, et al. Potential adverse cardiovascular effects from excessive endurance exercise. Mayo Clin Proc. 2012;87(6):587-95. Abstract: https://pmid.us/22677079 | Full Text: https://goo.gl/Q5MmQ

53. O’Keefe JH, Lavie CJ. Run for your life … at a comfortable speed and not too far. Heart. 2012 Nov 29. Abstract: https://pmid.us/23197444 | Full Text: Received from author.

54. Wilson MG, Whyte GP. Is life-long exercise damaging to the heart? Br J Sports Med. 2012 Jul;46(9):623-4. Epub 2012 Feb 16. Abstract: https://pmid.us/22345624 Full Text: Received from author.

55. Dorn GW 2nd. The fuzzy logic of physiological cardiac hypertrophy. Hypertension. 2007 May;49(5):962-70. Epub 2007 Mar 26. Abstract: http:/pmid.us/17389260 | Full Text: https://goo.gl/oTrHf

56. Lorell BH, Carabello BA. Left ventricular hypertrophy: pathogenesis, detection, and prognosis. Circulation. 2000 Jul 25;102(4):470-9. Abstract: https://pmid.us/10908222 | Full Text: https://goo.gl/Gc6lv

57. Patel DA, Lavie CJ, Milani RV, et al. Clinical Implications of Left Atrial Enlargement: A Review. Ochsner J. 2009 Winter; 9(4): 191–196. Full Text: https://goo.gl/umt0v

58. Voelkel NF, Quaife RA, Leinwand LA, et al. Right ventricular function and failure: report of a National Heart, Lung, and Blood Institute working group on cellular and molecular mechanisms of right heart failure. Circulation. 2006 Oct 24;114(17):1883-91. Abstract: https://pmid.us/17060398 | Full Text: https://goo.gl/TFFPZ

59. Levy D. Clinical significance of left ventricular hypertrophy: insights from the Framingham Study. J Cardiovasc Pharmacol. 1991;17 Suppl 2:S1-6. Abstract: https://pmid.us/1715449 | Full Text: NA

60. Kannel WB, Gordon T, Offutt D. Left ventricular hypertrophy by electrocardiogram. Prevalence, incidence, and mortality in the Framingham study. Ann Intern Med. 1969 Jul;71(1):89-105. Abstract: https://pmid.us/4239887 | Full Text: NA

61. Kannel WB, Gordon T, Castelli WP, et al. Electrocardiographic left ventricular hypertrophy and risk of coronary heart disease. The Framingham study. Ann Intern Med. 1970 Jun;72(6):813-22. Abstract: https://pmid.us/4247338 | Full Text: NA

62. Kannel WB. Left ventricular hypertrophy as a risk factor: the Framingham experience. J Hypertens Suppl. 1991 Dec;9(2):S3-8; discussion S8-9. Abstract: https://pmid.us/1838765 | Full Text: NA

63. Levy D, Garrison RJ, Savage DD, et al. Prognostic implications of echocardiographically determined left ventricular mass in the Framingham Heart Study. N Engl J Med. 1990;322:1561–1566. Abstract: https://pmid.us/2139921 | Full Text: https://goo.gl/iu8OY

64. Schillaci G, Verdecchia P, Porcellati C, et al. Continuous relation between left ventricular mass and cardiovascular risk in essential hypertension. Hypertension. 2000;35:580–586. Abstract: https://pmid.us/10679501 Full Text: https://goo.gl/7ETn2

65. Kahan T. The importance of left ventricular hypertrophy in human hypertension. J Hypertens Suppl. 1998 Sep;16(7):S23-9. Abstract: https://pmid.us/9855028 | Full Text: NA

66. Kahan T, Bergfeldt L. Left ventricular hypertrophy in hypertension: its arrhythmogenic potential. Heart. 2005 February; 91(2): 250–256. Full Text: https://goo.gl/ja2Wr

67. Wilson M, O’Hanlon R, Prasad S, et al. Diverse patterns of myocardial fibrosis in lifelong, veteran endurance athletes. J Appl Physiol. 2011 Jun;110(6):1622-6. Epub 2011 Feb 17. Abstract: https://pmid.us/21330616 | Full Text: https://goo.gl/IQF8f

68. Möhlenkamp S, Lehmann N, Breuckmann F, et al. Running: the risk of coronary events : Prevalence and prognostic relevance of coronary atherosclerosis in marathon runners. Eur Heart J. 2008;29(15):1903-10. Abstract: https://pmid.us/18426850 | Full Text: https://goo.gl/6kCP4

69. Breuckmann F, Möhlenkamp S, Nassenstein K, et al. Myocardial late gadolinium enhancement: prevalence, pattern, and prognostic relevance in marathon runners. Radiology. 2009 Apr;251(1):50-7. doi: 10.1148/radiol.2511081118. Abstract: https://pmid.us/19332846 | Full Text: https://goo.gl/RK4cr

70. La Gerche A, Burns AT, Mooney DJ, et al. Exercise-induced right ventricular dysfunction and structural remodelling in endurance athletes. Eur Heart J. 2012 Apr;33(8):998-1006. Epub 2011 Dec 6. | Abstract: https://pmid.us/22160404 | Full Text: Received from author (with editorial).

71. Nassenstein K, Breuckmann F, Lehmann N, et al. Left ventricular volumes and mass in marathon runners and their association with cardiovascular risk factors. Int J Cardiovasc Imaging. 2009 Jan;25(1):71-9. doi: 10.1007/s10554-008-9337-x. Epub 2008 Aug 3. Abstract: https://pmid.us/18677576 | Full Text: NA

72. Drazner MH. The progression of hypertensive heart disease. Circulation. 2011 Jan 25;123(3):327-34. Abstract: https://pmid.us/21263005 | Full Text: https://goo.gl/k6puL

73. Bhella PS, Levine BD. The Heart of a Champion. J Am Coll Cardiol. 2010;55(15):1626-1628. doi:10.1016/j.jacc.2009.12.030. Abstract: https://pmid.us/20378082 Full Text: https://goo.gl/TYG6W

74. Green DJ, Naylor LH, George K. Cardiac and vascular adaptations to exercise. Curr Opin Clin Nutr Metab Care. 2006 Nov;9(6):677-84. Abstract: https://pmid.us/17053419  | Full Text: https://goo.gl/hj036

75. Baggish AL. Email communication. Message to the author. Dec 11, 2012.

76. Baggish AL, Wood MJ. Athlete’s heart and cardiovascular care of the athlete: scientific and clinical update. Circulation. 2011 Jun 14;123(23):2723-35. Abstract: https://pmid.us/21670241 | Full Text: https://goo.gl/fWiEj

77. Hildick-Smith DJ, Shapiro LM. Echocardiographic differentiation of pathological and physiological left ventricular hypertrophy. Heart. 2001 Jun;85(6):615-9. Abstract: https://pmid/11359735 | Full Text: https://goo.gl/kr8wy

78. Maron BJ, Pelliccia A. The heart of trained athletes: cardiac remodeling and the risks of sports, including sudden death. Circulation. 2006 Oct 10;114(15):1633-44. Abstract: https://pmid.us/17030703 | Full Text: https://goo.gl/qirCb | Author Contact: <hcm.maron@mhif.org>

79. Maron BJ, Pelliccia A. The heart of trained athletes: cardiac remodeling and the risks of sports, including sudden death. Circulation. 2006 Oct 10;114(15):1633-44. Abstract: https://pmid.us/17030703 | Full Text: https://goo.gl/qirCb | Author Contact: <hcm.maron@mhif.org>

80. Maron BJ, Pelliccia A. The heart of trained athletes: cardiac remodeling and the risks of sports, including sudden death. Circulation. 2006 Oct 10;114(15):1633-44. Abstract: https://pmid.us/17030703 | Full Text: https://goo.gl/qirCb | Author Contact: <hcm.maron@mhif.org>

Leave a Comment