By Ty Wheeler
Firefighting is a strenuous profession. It demands a great deal of physical endurance and strength-probably more so than just about any other occupation. It is clear now more than ever: We need to be in top physical shape to perform in these harsh conditions.
We are all aware of the line-of-duty deaths (LODDs) related to cardiovascular compromise. They account for nearly 50 percent of all firefighter fatalities annually. When we correlate the United States Fire Administration’s firefighter fatality statistics with the Center for Disease Control’s National Institute for Occupational Safety and Health (NIOSH) reports on cardiac-related LODDs, we find two standard recommendations: (1) “Expand or implement periodic medical evaluations per National Fire Protection Association 1582, Standard on Selection, Care, and Maintenance of Open-Circuit Self-Contained Breathing Apparatus (SCBA) …”; and (2) “Implement a mandatory wellness/fitness program to reduce the risk of cardiovascular disease and improve cardiovascular function.”
In addition to the NIOSH recommendations, research on the subject of firefighter health and fitness consistently produces the same conclusions and recommendations. For example, Baur, et.al. assert that, “Low CRF (cardiorespiratory fitness) is an important risk factor for the development of obesity, hypertension, and other cardiovascular risk factors as well as coronary heart disease, stroke ….”1 Although these issues have been brought to the forefront of the fire service, we still see a lack of commitment and understanding by firefighters on how to improve their physical fitness and a general oversight by department heads to implement such programs.
Cardiovascular Fitness
There are several key measurements that can help predict the overall well-being of a firefighter. One of the most important is cardiovascular fitness. Cardiovascular fitness is an important aspect of firefighting because of the stress the body endures during firefighting operations.
Cardiovascular fitness should be a top priority in any firefighter fitness program, but it must also be appropriate for the work that we do. Whether you’re a CrossFitter or a power lifter, a firefighter or a football player, your fitness regimen must be tailored to your work to gain the most benefit. A study published by Dr. Shehab Mahmoud Abd El- Kader in the European Journal of General Medicine stated that the “significant increase in VO2 max is related to the effect of exercise either aerobic or anaerobic and improves the respiratory function as vital capacity, inspiratory reserve volume, and expiratory reserve volume of the lungs, also the stroke volume of the heart increase by regular exercise.”2
Oxygen Uptake
To fully understand this assertion, we must first understand oxygen uptake, which, according to the National Strength and Conditioning Association (NSCA), is the amount of oxygen consumed by the body’s tissue.3 This value is related to the amount of work being performed by the body. When the body’s muscles are working harder, the oxygen demands will be greater; therefore, more oxygen will be consumed to be transported to the body’s tissue to continue to perform the work. When larger muscles are involved in the activity, the amount of oxygen needs increases.
Oxygen demands are also influenced by the environment, personal protective equipment, and internal and external stresses. The body can only use so much oxygen. This is referred to as maximal oxygen uptake (VO2 max) and is described as the greatest amount of oxygen that can be used at the cellular level for the entire body. (3) To simplify, when performing strenuous work, you will eventually reach your VO2 max, at which point you will no longer be able to work any harder. This value is considered one of the best assessments of cardiorespiratory fitness in the fitness industry.
A study performed by the New England Journal of Medicine discusses VO2 max: “Exercise capacity is a more powerful predictor of mortality among men than other established risk factors for cardiovascular disease.”4 It also has been reported by the Journal of Obesity that, “Cardiorespiratory fitness declines with aging general population … about 1.6 percent per year … decline in peak VO2 five percent-10 percent per decade.”(1)
How does this translate to the fire service? Oxygen uptake is determined by the amount of work being performed. So, if we have a limited air supply and reach our VO2 max, we have reached the greatest effort we can give. If we are stretching line into an apartment fire up smoke-filled stairs, we are already using our SCBA air supply and increasing our oxygen demand because of the restricted breathing we encounter with the apparatus (usually around a 15 percent reduction). When we reach the top of the stairs and start to make the push, we need to be able to continue to perform our job, even as the conditions we enter may get worse. At this point, we are already reaching extreme heart rate, and our VO2 has already significantly increased. Our oxygen is getting consumed at a higher rate because of the intensity of the activities being performed. If something occurs during these typical firefighting tasks that requires even more physical effort (such as the need for self-rescue or victim removal), are you going to be able to perform, or have you already reached your VO2 max?
The Nuts and Bolts of VO2 max
VO2 max is a scientific assessment completed by a trained provider, either a physician or a certified trainer. This test requires a cardio machine, typically a treadmill, but steppers, rowers, or a bike can be used. A VO2 max machine (metabolic assessment machine) will be connected to the participant and to a computer to capture statistics live. To determine aerobic capacity, the machine will measure oxygen consumption and carbon dioxide as well as total volume of air exchange. In addition, maximal heart rate, lactate acid threshold, and anabolic threshold data might be gathered as well, depending on your evaluator.
The test is completed with a mask over the candidate’s mouth and nose with a hose to the VO2 machine, and the candidate is typically hooked up to a heart rate monitor. The test begins with a slow walk or easy cardio exercise. As the test progresses, the difficulty of the aerobic exercise will increase in increments until the candidate reaches the maximal intensity. At this point, the test will be stopped and results will be produced. Testing your VO2 max will vary depending on your location. This test is not available at every hospital or physical therapy facility, but sports medicine and sport performance facilities are going to be the best places to start.
The Regimen
Studies have discovered firefighting activities require a VO2 max of 33.9 to 45mL/kg/min to safely perform the required tasks on the fireground. Once you have determined your current VO2 max, you can develop a regimen, as prescribed by your physical fitness coordinator, strength and conditioning coach, or physician. In general, a program of high-intensity interval training or metabolic conditioning tailored to your fitness level should be designed.
What to Expect
The results of implementing a cardiovascular improvement regimen will vary, but they can range from a five- to a 30-percent increase in VO2 max over a six- to 12-month period. (3) When performing these training intervals, it is important to note other physiological changes also take place. According to the NSCA, these changes include increased respiratory capacity, lower blood lactate concentration, increased mitochondrial and capillary density, and improved enzyme activity. (3)
Many great resources are out there to determine what exercise is best for your personal goals; each needs to be tailored to your fitness level. When starting a program, it is recommended you consult your physician and complete a health assessment.
The First Step
Firefighting is a physically demanding profession. As previously discussed, VO2 max is a big factor in a firefighter’s overall fitness and is a predictor of overall well-being and ability to perform our duties. Determining your VO2 max is a great starting point as you move forward on your fitness journey.
References
1. Baur, D. M., Christophi, C. A., Francis Cook, E., and Kales, S. N. “Age-Related Decline in Cardiorespiratory Fitness among Career Firefighters: Modification by
Physical Activity and Adiposity,” Journal of Obesity, 2012, 1-6.
2. Abd El- Kader, Shehab Mahmoud, “Aerobic Exercise Training Improves Cardiopulmonary Fitness among Firefighters,” European Journal of General Medicine, December 2010, 352-358.
3. National Strength and Conditioning Association, Essentials of Strength Training and Conditioning, 2015.
4. Myers, J., Prakash, M., Froelicher, V., Do, D., Partington, S., and Atwood, J. E. “Exercise capacity and mortality among men referred for exercise testing,” New England Journal of Medicine, 2002, 346(11), 793-801.
