Oxygen Debt

By Michael Krueger

Firefighting is the only profession that has equipment specifically designed to give you fair warning when you are running low on air. Your mask rumbles and you know you have to get out–now. You meticulously maintain the equipment that keeps you alive–your mask, regulator, and tank.

Your body will give a warning that something is wrong, too, but it often comes in the form of chest pains, a heart attack, and death. Perhaps it’s time to spend as much time on your personal survival equipment as you do on your professional survival equipment.


VO2 Max

Your VO2 max represents the maximum amount of oxygen your body can process to produce energy. Your VO2 max, the basic number, reflects the limitations of your cardiovascular system to transport oxygen to your working muscles as well as your working muscles to use it. This includes your heart and diaphragm. In other words, your VO2 max defines how much can you do and for how long before you have to stop.

You can boost you VO2 max through training, but there are many factors aside from training that will reflect in you final score. Your genetics, age, and gender as well as your familiarity with the protocols of any particular test will make a difference on your outcome. Because of that, it is important not to become fixated on the number per se but rather think about how your performance reflects on your overall fitness as well as how well you respond to your firefighting challenges.

It has been shown that inactive individuals, those who quite frankly would avoid any type of exertion if possible, were at 90 percent greater risk of myocardial infarction than those who are aerobically fit. Your VO2 max is one way to judge your aerobic fitness. The clinical treadmill test is tough and involves using a mouthpiece to collect and measure inhaled and exhaled gases and is usually administered only to those who are fit enough to endure it. There are sub maximal tests that have been devised to assess those who either do not have access to the equipment necessary to administer a maximal test or for those untrained, unfit, or ill individuals for whom a maximal test is contraindicated. Generally speaking, the higher your VO2 max the fitter you are, but these tests are not the be all and end all of fitness. There are too many variables for it to be that simple.

I wouldn’t recommend using the values obtained by these tests as a measure of one’s fitness to do a particular job. What they are good for is gauging your current fitness level and the improvement that you achieve through training.


Real-Life Applications

Posturing and bravado aside, you know full well how fit you are. You know if you are the first one to have to leave a fire because you are running out of air. You know if you are exhausted after a training evolution. You know if you are fat. You know if you are weak. It doesn’t matter if other people don’t seem to be aware of these facts (but trust me, they are); you do. Rationalizing it, hiding from it, or ignoring it until it causes real problems for you or for someone else is not a realistic or ethical course of action; however, doing something about it is.

The best nonclinical activity to judge aerobic fitness involves running. I also know that anyone who doesn’t normally run doesn’t run for a reason and that reason is he hates running. Just plain running for the simple health benefits is hard enough on its own, but if you move into the realm of training to improve performance, it’s uncomfortable to say the least. The point is, if you hate running, you need to ask yourself why. There are legitimate reasons (I guess) to hate to run. It might be simply a mechanical thing: You feel ungainly or clumsy or perhaps it irritates a previous injury or it bothers your knee, ankle, or whatever. That is understandable. If the reason you hate running is because you aren’t aerobically fit enough to be able to do it, that is a different story altogether.

You are a firefighter and, as such, you have no choice but to be fit, and there are many other options besides running to become aerobically fit. You can incorporate your firefighting skills to achieve this end as well. Raising and climbing ladders are a good start. Chopping, repeatedly whacking a tire with a sledgehammer, and humping hoses up stairs are good choices. Remember that you aren’t looking for something “easier” than running, just an activity that is more palatable to you. Whatever you do, it is supposed to be hard. In fact, on the cardiovascular front, it should be as uncomfortable and demanding as running would be for you.



Some firefighters might cynically say that they are physically “fit enough” for what they need to do, and you know they are probably right. Under normal circumstances, today, right now, they would probably do OK. But the question is, how will they be in a year, or two, or five? What happens when something really cataclysmic and out of the ordinary happens? Another thing to consider: Is “fit enough” good enough? Even if you can do everything required of you, and your training officer is satisfied with your level of fitness, should you be?

You may take an annual physical and all your numbers are “normal.” You may pass all of the minimal skills tests, so you are minimally skilled. You may be the fasted, strongest, and fittest person on the department, but it doesn’t matter if everyone else is just slightly less average than you.

Fire departments need fitness leaders who can create a positive physical culture. The department needs to be a place where good nutrition and effective exercise are the norm, not the exception. The desire to be the best you can be physically will drive you to excel in all aspects of your life, professionally and personally.

Of course, not everyone is cut out to be a leader. That is good; we can’t all be leaders. For those who are followers, you need to be the best follower you can be. You need to listen and learn, train and improve. Occasionally, there are members who undermine fitness programs for their own misguided reasons. Some just don’t want to participate because they are lazy or claim to not see the efficacy of the program. Some are hiding physical problems or illnesses that they fear may jeopardize their career if anyone found out. Others are just toxic when it comes to any idea that wasn’t theirs. These people need to be confronted, reassured, shown the error of their ways, and then brought back into the fold. It’s not always easy, but this is what leaders do.



This is where ethical behavior, personal responsibility, and self-respect enter the equation. If you want to be the best firefighter on the department, you should be willing to put in the gym time, the track time, the practice ground time, and the classroom time that it takes to be the best.

It’s always possible to improve your fitness, your skills, or your character. You can always be a better leader or a better follower. Constantly challenge yourself physically and mentally so that when the challenges come from outside of yourself, you will know you are ready in every way for whatever life serves up.


Michael Krueger is an NSCA-certified personal trainer. He got his start in fitness training while serving in the United States Coast Guard. He works with firefighters and others in and around Madison, Wisconsin. He is available to fire departments, civic organizations, and athletic teams for training, consulting, and speaking engagements. He has published numerous articles on fitness, health, and the mind-body connection and was a featured speaker at the IAFC’s FRI 2009 Health Day in Dallas, Texas. E-mail him at MKPTLLC@gmail.com.


Previous articleThe Job: Dispatch Training
Next articleMissing New Mexico Firefighter Found Dead

No posts to display