What is exercise induced cardiac remodeling?

What is exercise induced cardiac remodeling?

Repetitive participation in vigorous physical exercise is associated with significant changes in myocardial structure and function. This process has been called exercise induced cardiac remodeling [1]. It is characterized by left ventricular hypertrophy which could be eccentric or concentric depending on the type of exercise. Exercise induced cardiac remodeling is associated with changes in both systolic and diastolic function.

Cardiac enlargement in trained athletes has been documented as early as 1899 [2,3]. They noted enlargement of cardiac silhouettes in skiers and rowers. Features of athlete’s heart on multimodality imaging include balanced biventricular dilatation, mild to moderate increases in left ventricular wall thickness and biatrial dilatation [4].

The stimulus for exercise induced cardiomyopathy is a continuous variable defined by the cross product of intensity, frequency and duration of exercise [5]. Exercise induced cardiac remodeling can also occur in adults with moderate physical activity [6]. 1096 adults with median age of 39 years, without cardiovascular disease or cardiomyopathy associated genetic variants underwent cardiac magnetic resonance imaging to determine biventricular function. Increasing physical activity was associated with greater left ventricular mass, and elevated volumes of left and right ventricles. The effect of physical activity on cardiac structure was larger than that of systolic blood pressure and similar to that of age.

Regular physical activity is strongly associated with reduction in all cause mortality compared to a sedentary lifestyle  and even moderate physical activity [7]. The proposed mechanisms are a decrease in myocardial oxygen demand, better myocardial perfusion and lower cardiovascular risk factors like hypertension, diabetes mellitus and obesity [8].

References

1. Weiner RB, Baggish AL. Exercise-induced cardiac remodeling. Prog Cardiovasc Dis. 2012 Mar-Apr;54(5):380-6. doi: 10.1016/j.pcad.2012.01.006. PMID: 22386288.
2. Henschen S.Skidlauf und Skidwettlauf. Eine medizinische Sportstudie.Mitt Med Klin Upsala. 1899; 2.
3. Darling EA.The effects of training. A study of the Harvard University Crews.Boston Med Surg J. 1899; CXLI:229–233.
4. Baggish AL. Exercise-Induced Cardiac Remodeling: Competitive Athletes Are Just the Tip of the Iceberg. Circ Cardiovasc Imaging. 2016 Aug;9(8):e005321. doi: 10.1161/CIRCIMAGING.116.005321. PMID: 27502062.
5. Wasfy MM, Baggish AL. Exercise Dose in Clinical Practice. Circulation. 2016 Jun 7;133(23):2297-313. doi: 10.1161/CIRCULATIONAHA.116.018093. PMID: 27267537; PMCID: PMC4902280.
6. Dawes TJ, Corden B, Cotter S, de Marvao A, Walsh R, Ware JS, Cook SA, O’Regan DP. Moderate Physical Activity in Healthy Adults Is Associated With Cardiac Remodeling. Circ Cardiovasc Imaging. 2016 Aug;9(8):e004712. doi: 10.1161/CIRCIMAGING.116.004712. PMID: 27502059; PMCID: PMC4991346.
7. Löllgen H, Böckenhoff A, Knapp G. Physical activity and all-cause mortality: an updated meta-analysis with different intensity categories. Int J Sports Med. 2009 Mar;30(3):213-24. doi: 10.1055/s-0028-1128150. Epub 2009 Feb 6. PMID: 19199202.
8. Dores H, Freitas A, Malhotra A, Mendes M, Sharma S. The hearts of competitive athletes: an up-to-date overview of exercise-induced cardiac adaptations. Rev Port Cardiol. 2015 Jan;34(1):51-64. doi: 10.1016/j.repc.2014.07.010. Epub 2015 Jan 7. PMID: 25575633.