Artery Stiffness and Muscle Recovery
Lifting for athletes is an essential component of peak performance, but is known to take a toll on the body in various ways. Specifically from in this article review we will be discussing the negative oxidative stress put on our bodies. This oxidative stress has been suspected to increase the muscle damage during recovery (slowing down recovery time), as well as increasing stiffness in our arteries. Everyone knows the detrimental effect of slow recovery time on athletic performance, but the stiffness of arteries is not such a simple correlation.
Artery stiffness mainly relates back to general health and longevity. Ideally, we want to maintain well lubricated flexible arteries to give as little resistance as possible to the blood pumping through us. As we grow older, our veins and arteries naturally become stiffer, allowing other problems to arise like plaque buildup, and higher blood pressure. For this specific experiment, they used “Carotid-Femoral Pulse Wave Velocity” (cfPWV) as an indicator of stiffness, which is a fancy way of saying that they tracked the speed of blood flow from the upper body to the lower body, specifically at the carotid artery (upper body) and femoral artery (lower body). In addition to cfPWV, researchers also collected blood samples to observe markers for muscle damage (creatine kinase and myoglobin), and oxidative stress (malondialdehyde (MDA)),
Due to oxidative stress, acute arterial stiffness, and DOMS (delayed onset muscle soreness) all being a delayed reaction to lifting of about 48 hours, experimenters wanted test if oxidative stress was a primary factor by testing control groups against an anti-oxidative supplement, taurine. Taurine is a conditional amino acid found best found in meat and fish. This differs from essential amino acids because conditional amino acids can be produced by the body, whereas essential amino acids must be supplemented from the diet. Taurine is already often prescribed to treat disorders of the circulatory system like high blood pressure or congestive heart failure, but little is still known on the details of this cause and effect relationship.
In this study, 29 healthy men were split into a placebo (control) group and a taurine group. Prior to the single bout of exercise, the taurine group was supplemented with 2g of taurine three times a day for 14 days to raise their blood-taurine levels about 2-fold compared to normal. All 29 subject then performed a bout of exercise on the 15th day, which consisted of two sets of 20 repetitions of bicep curls on a machine that controlled the speed to a three second eccentric phase. This was performed only with their non-dominant hand. After exercise, this study observed the subjects for 4 additional days post-exercise.
As expected, by day two post-exercise their markers indicated that muscle damage and arterial stiffness was occurring. On the final two days of the experiment, day three and four post-exercise, there emerged significant differences between the control and taurine groups. Graph (A) below looked at MDA, their variable related to oxidative stress, and while the taurine group did experience some change, it was miniscule compared to what is assumed to be a normal effect from the placebo group. Graph (B) followed suit showing almost no change in arterial stiffness after exercise in comparison to the significantly affected control group. The table below noted muscle damage in the bottom two rows with creatine kinase and myoglobin. The final two days comparison also revealed strong significance compared to the control groups, the control group notably had about twice the amount of creatine kinase in their blood tests.
The decreases of muscle damage supports previous study findings that had observed soreness after a single bout of exercise, but in addition this study was able to give blood profiles to quantify the extent of muscle damage. This was also the first study of its kind to observe a correlation between oxidative stress and arterial stiffness after exercise, supporting the hypothesis that there is a cause and effect relationship between these variables. The study’s findings were also notable to show that taurine may act as an oxidative stress protection supplement in humans, whereas previous studies had only shown this relationship in animals.
Researchers believe that there was an additive effect from the taurine increasing nitric oxide’s (NO) contribution post-exercise in the body. NO counters the constriction of our veins and arteries, which in turn also reduces arterial stiffness and has other positive cardiovascular health benefits. One drawback from this study, was that the researchers could not compare taurine levels post-exercise to any other markers because they only tested these levels leading up to the bout of exercise. This would have been useful to draw further conclusions if NO was closely correlated to taurine levels, giving further indication of a relationship. Lastly, even though this study shows heavy promise in reducing muscle damage/soreness and arterial stiffness, further research is needed to see if these effects would hold true with elderly or female populations, and if these same trends hold true for multiple bouts of exercise throughout a lifting cycle consisting of weeks or months.
About the Author
Jack Rummells, PhD Candidate, NFL
Lifting is my religion. My interest for the iron began at age 13 doing strongman out of my first mentor’s garage. This evolved into competing in Olympic Weightlifting and Strongman through high school and college. At the University of Northern Iowa, I received a B.A. and M.A. in kinesiology, as well as All- American honors on the football field as a left tackle. In 2015, I was lucky enough to join the Jacksonville Jaguars roster for 6 months. After I was released from the Jaguars, I had the opportunity to train for a month learning the conjugate method from Louie Simmons at Westside, and a month later I placed 12th overall in the 105+ division at the American Open in Olympic Weightlifting. Currently, I’m back at school pursuing my PhD in Biomedical Engineering at the University of Iowa… And yes, the fire still burns strong.