Cardiac Hypertrophy: The Effects of Exercise on Your Heart

The body’s adaptation to physiological stress is certainly a wonder to behold. Unfortunately, all too often we get caught up in the superficial outcomes of our training (i.e. muscle gain & fat loss) leading us to disregard the equally important internal changes that are occurring because of our efforts.

One of the major organs affected by any type of training is the heart. Endurance exercise training, such as long distance running or swimming (aerobic activity) result in cardiac hypertrophy (growth), increased cardiac output and increased ventricular stroke volume. This is known as ‘eccentric’ remodeling of the heart. In contrast, physical conditions that emphasize strength training only modestly increase cardiac output, but result in ‘concentric’ growth accompanied by increased peripheral vascular resistance. What does this mean? Basically, the heart’s vascular system, ventricles, etc getsmaller and more restricted. 

The research suggests that concentric hypertrophy leads to increases in blood pressure, leading to the recommendation that strength training should be avoided for obvious reasons. However, I disagree. 

Resistance training is not associated with an ‘across-the-board’ alteration in cardiac hypertrophy. In fact, concentric cardiac hypertrophy is more often found in Olympic weightlifters, rather than bodybuilders. Overall, resistance training is rarely associated with an acute or chronic alteration in the systolic function of the heart (which refers to ventricular contraction). 

Recommendations:

So, should you pass on the weights in favour for the treadmill? I think not. However, I would incorporate some aerobic training into your weekly routine to ensure a you’re receiving the benefits of both forms of exercise. For those of you who can’t bear to look at a stationary bike, I would suggest taking up a martial art as the ideal way to get your cardio fix for the week. The stop-start nature of classes will provide you with an interval based workout that will challenge you both mind and body.

References:

Dorn, G. W. (2007). The fuzzy logic of physiological cardiac hypertrophy. Hypertension, 49, 962-970.

Haykowsky, M. J., et. al. (2002). Resistance training and cardiac hypertrophy: Unravelling the training effect. Sports Med, 32(13), 837-849.

Mihl, C., Dassen, W.R.M., & Kuipers, H. (2008). Cardiac remodelling: Concentric versus eccentric hypertrophy in endurance athletes. Neth Heart J, 16(4), 129-133.