By now, most people are aware of the dangers of smoking. Lung cancer, cardiovascular disease, shortened life span--to name a few--and the vast list of health concerns associated with smoking continues to grow. But a side effect of smoking that not many people may be aware of is its effect on muscle growth.
How Does Muscle Grow?
During strength training exercises, fibers in the targeted muscles actually become damaged in a process known as “muscle injury.” Young sub Kwon, M.S. and Len Kravitz, Ph.D. of the University of New Mexico explain that when muscle injury occurs, cells rush to the area and begin to fuse forming new fibers referred to as “myofibrils.”
Burning Muscle—Not Fat
Aside from strengthening the cardiovascular system and gaining muscle, most people that exercise also hope to burn fat. Unfortunately, if you are a smoker this may not be possible. In fact, Fairfax Digital reports that smoking decreases your appetite and causes you to lose weight, but it is usually only muscle weight that is lost. Therefore, any muscle growth that is gained through strength training can be easily lost with the next pack of cigarettes.
Nicotine and Insulin
According to MuscleNet.com, the nicotine in cigarettes causes the body to become insulin resistant. Meaning that, smoking has a direct impact on the way muscle metabolizes insulin and blood glucose. Since glycogen replenishment is especially important to muscle recovery, muscle growth in smokers is significantly reduced in comparison to that of nonsmokers.
Protein synthesis is a necessary part of muscle growth. During strength training the amount of protein synthesis that the body undergoes is reduced but it picks up again once exercise has ceased. The University of Nottingham reports that smoking inhibits muscle growth by interfering with the protein synthesis process.
Muscle growth in some people is sometimes reduced by an enzyme known as myostatin. According to Bio-Medicine.org, smokers have a higher amount of myostatin than nonsmokers. This also appears to play a role in the muscle loss associated with active smokers.