Busting One of the Biggest Myths about Firefighters and Muscle

Have you ever observed someone, perhaps a fellow firefighter, who has seemingly “converted” from being a very muscular person to a very overweight person? Often people believe this occurs when a person’s muscle tissue turns into fat; but that is a myth. Muscle DOES NOT turn into fat.


Muscle cells are long cylinder shaped fibers while fat cells are little round plump guys. They do not convert into one another. Our bodies create more fat cells when we take in excess food. Both fat and muscle cells can enlarge (hypertrophy) and get smaller (atrophy).

So here is the real explanation. Contrary to the way we lose our cardiovascular fitness (I’ll discuss that next week), we do not easily lose muscle once it is gained. It takes little physical effort to maintain muscle mass and strength. In fact, the American College of Sports Medicine recommends 1 day per week of strength training for people who only want to maintain the muscle that they have (note that it takes more work to gain muscle). Since firefighting is a physically demanding job, it can be easy to maintain muscle mass. Case in point: I do fitness tests on hundreds of my local firefighters every year and some tell me that while they still possess a ton of strength, they haven’t lifted weights since high school.

To be clear, you can lose muscle mass by losing weight. Depending on the method used to achieve weight loss, the loss may be comprised of 75% fat mass and 25% lean mass.

Muscle mass begins to decline naturally around age 30, but this decline is almost negligible. It is not until about age 50 that the aging process begins to accelerate muscle loss. Typically, large decreases in strength do not even occur until closer to age 70 (perhaps “old man strength” isn’t an unexplainable phenomenon after all). So you’ve probably put it together by now: people who seemingly convert from being very muscular to very overweight are simply gaining fat on top of all their muscle, which makes them look massive.

Hey, I see this as really good news: these people have less fat to lose than it appears. And they don’t have to get back in the weight room to get back to what they once were. Simply losing fat by a) eating fewer calories, b) burning more calories through cardiovascular exercise, is the clear solution.


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By | 2018-06-01T08:08:23+00:00 May 8th, 2013|Uncategorized|Comments Off on Busting One of the Biggest Myths about Firefighters and Muscle

About the Author:

Dr. Karlie Moore has a PhD in Exercise Science and Nutrition and specializes in firefighter health. She has conducted fitness testing on hundreds of firefighters and has created the most comprehensive online wellness program for fire departments called the FitCulture program. Dr. Moore is also married to a firefighter and so understands their lifestyle and the health challenges associated with it.