Everything that is done repeatedly causes adaptations in the body. This is why we exercise with weights. After performing a sufficient amount of strength training our body adapts in several ways, one of which is bigger and stronger muscles. However, some of the potentially negative adaptations that occur in the body have not been addressed in the mainstream bodybuilding publications. Below you will find out just what negative things strength training is doing to your body, and how a simple cardiovascular training protocol can help to mitigate these effects.

When you lift weights blood is pumped to your muscles to bring nutrients and flush out waste products. This helps to improve endurance during your sets. Over time your body gets better and better at pumping blood to your muscles. One of the main adaptations in your body that occurs to facilitate better blood flow is a thickening of the left ventricular wall of your heart. This thickening allows for more blood flow during those heavy sets, but it also has negative affects on your health. Thickening of the left ventricular wall causes blood to be pumped from the heart more forcefully. The blood vessels respond by becoming more rigid to withstand this pressure. The blood vessels can also develop small tears which become inflamed. This is where atherosclerotic plaque can begin to build up. All of these things lead to an unhealthy cardiovascular system that is at risk for a heart attack.

One of the other things that happens during weight training is the activation of the sympathetic branch of the nervous system. This is typically known as the “fight or flight” branch. When the sympathetic branch is activated it causes a release of the chemicals epinephrine and nor-epinephrine, which are commonly referred to as adrenaline. These chemicals can greatly enhance your strength. However, if you are constantly calling on the sympathetic branch of your nervous system it adapts by becoming more easily activated or by staying activated. This leads to what is known as “sympathetic dominance.” This essentially puts your body into “fight or flight” mode all of the time. As you may guess, this is very stressful on all of the body’s systems and not conducive to recovery from exercise.

So how do we correct these two issues? Well, there are many different corrective methods out there, and not all people will respond the same to any one method. However, in my work with professional athletes I found that one of the simplest methods is also one of the most effective. This method is simple cardiovascular exercise.

Everyone has heard about the health benefits of cardiovascular exercise. Many people also use cardiovascular exercise for fat loss (even though this is not the quickest method for fat loss).

However, most of us who are serious about weight training have heard at one time or another that cardiovascular exercise is actually detrimental to muscle and strength gains. While this is true with certain types of cardiovascular exercise, it is completely incorrect for other types. However, many lifters have adopted a negative view of cardio and hence neglect to incorporate it into their programs for fear of losing muscle. With this in mind, let’s look at how performing cardio can actually increase your strength and muscle gains, much more than weight training alone.

As mentioned above, two of the unhealthy adaptations that occur from prolonged strength training are:
1. Thickening of the left ventricular wall of the heart
2. Sympathetic dominance in the nervous system

Low-intensity cardiovascular exercise can correct both of these issues. By activating the parasympathetic branch (the rest and relaxation branch) of the nervous system, the sympathetic branch’s influence is diminished and the body is shifted to a state in which it can begin recovery. Low-intensity cardio also helps to stretch the left ventricular wall of the heart which makes the wall more pliable over time. This allows better blood flow to all of the body while at rest. Blood flow to the muscles is a huge component of recovery, and this is an easy way to promote it. To receive these benefits the key is the intensity and duration of the cardiovascular exercise.

The protocol is simple:

2-3 times per week, 45-60 minutes, heart rate of 120-130 bpm

This means that you can pick any exercise you want: treadmill, bike, elliptical, stairs, etc. Most people find all of these options boring, so I would recommend some other activity (walking outside, shooting hoops, playing with your kids, etc.). The only requirement is that you do it for at least 45 minutes and that your heart rate stays between 120 and 130 beats per minute (bpm) the whole time. What you don’t want is an activity where you have to sprint hard and then rest. This causes the heart rate to increase quickly and then slow down again. This type of training is similar to weight training and will only make recovery more difficult.
What you want is very low intensity cardio. This will not eat up muscle glycogen or harm your ability to gain muscle mass. To the contrary, it will stimulate the parasympathetic branch of the nervous system and improve blood flow to your damaged muscle fibers. This helps you to not only recover more quickly between training sessions, but between sets as well.

Remember that training hard is only half the battle. The limiting factor for muscle growth is the ability to recover between training sessions. Using effective strategies like low-intensity cardio to enhance your recovery will help your muscle gains skyrocket!