It is well established that aerobic exercise increases the elastic properties of the arteries. This is a very positive adaptation as the compliance of our blood vessels plays an important role in predicting cardiovascular events. Until recently, physicians and researchers assumed that intense resistance training reduces the compliance of our major blood vessels; of course, this is a bad thing as increased “stiffness” of the blood vessels predisposes us to cardiovascular disease. However, very little research has existed to support this contention.
Authors of a research study published in the Journal of Hypertension (February 2014) sought to determine the impact of long-term, intense strength training on arterial “stiffness.” The researchers concluded, “Long-term intense resistance training in men decreased aortic stiffness… and preserved cardiac structure/function when compared with well matched untrained healthy controls.” This important study contributes to the growing body of literature that represents a paradigm shift from defining the benefits of resistance exercise as increased muscle strength, bone health, and body composition, to a more robust profile of cardio-metabolic health benefits. Indeed, “strength training” is more properly coined, “resistance exercise.”
- It is well accepted that aerobic exercise increases the elastic properties of central arteries (elasticity in our vessels is important in preventing cardiovascular disease!)
- The research and/or opinions on whether or not strength training is good or bad for the elasticity of our vessels is mixed (and much of the thought is that strength training REDUCES elasticity AKA “compliance” of the vessel… and this is why many cardiologists have been anti-strength training.)
- This was a longer term study with trained runners and trained strength training subjects (and the strength training group had to have been strength training 5 times per week!)… The researchers even speculated that half of the strength training participants were on steroids!
- Subjects were in their mid-30’s
- Endurance running led to improvements in vascular function – “We confirmed that long-term endurance training is associated with the classical cardiovascular and hemodynamic adaptations and with decreased aortic stiffness.”
- Main finding: Our main finding was that long-term intense resistance training men presented decreased aortic stiffness (PWV values similar to endurance runners) and lower cAP, a trend to longer T1 and Trw, normal central aortic pressures, and preserved cardiac structure/function when compared with well matched untrained healthy controls.
- In conclusion, besides the benefits of improvements in the musculoskeletal functions, it seems that long-term IRT is not associated with detrimental effects on central artery elastic properties or wave reflection or cardiovascular structure and function of healthy individuals.
Take home message in simplest terms: It has long been assumed that intense strength training over a long period of time has a negative impact on artery/vessel elasticity and function (this is a bad thing). The results of this study show that intense strength training actually improves elasticity (i.e. Decreased aortic stiffness) in healthy adults (a good thing!).