What Is Aerobic Capacity and What Does Research Say?
Aerobic capacity is the ability of the body to utilize oxygen and is measured in milliliters of oxygen per kilogram of body weight per minute.
Aerobic Capacity is a fitness test and is not health screening for cardiac disease. Aerobic Capacity measurements are necessary for exercise prescriptions.
If a firefighter is healthy, he/she can be physically fit. Without health there can be no fitness. Therefore, all programs should begin with a physical examination that is medically and academically verifiable.
What does the American Heart Association and the American College of Sports Medicine say about cardiac stress testing? What does research say — Use acceptable methods for 12 lead, EKG monitored graded exercise stress testing.
Aerobic Capacity research in the fire service was published over 30 years ago by the University of Wisconsin. This research stated that 37.5 ml/kg/min is the minimum to participate as a structural firefighter. This is a physically prepared to perform member. The question to be answered before this becomes applicable is, “Is the firefighter healthy enough to participate in the structural fire service?”
OSHA 1910.156 is over 30 years old, but it is still a regulation and not a recommendation. The 55 mile per hour speed limit is over 80 years old, but it is still a law on many roads.
The following is a direct quote from Dr. Joseph Henderson of Carolina Cardiology Consultants of Greenville, SC:
“It is true that coronary artery calcium score and measurement of carotid intimal thickness can help identify preclinical atherosclerosis. These tests, when abnormal, may prompt patients to seek earlier treatment of cholesterol evaluation and help prevent future events but perhaps more relevant to the testing of firefighters is an exercise stress test which assesses their exercise capacity and documents whether or not they have symptoms or signs of myocardial ischemia at high levels of physical stress. The program should also offer lipid screening which can be an opportunity for patients to seek advice from their physician about treatment to prevent future cardiovascular events.
“No noninvasive cardiac test is perfect at predicting all adverse cardiac events, but before clearing a firefighter for duty, some form of exercise stress test would be necessary to assess immediate risks for the high demands of fire fighting.”
Dr. Henderson’s quote also broaches the subject of calcium scans, which is self explanatory.
It is stated in NFPA 1582 that a bike test should not be used and this applies to aerobic capacity testing. Read this section very carefully. It does not negate the American Heart Association guidelines for cardiac screening/testing. The research study published by Barry University of 2003 is very clear in that the Gerkin Protocol should not be used to determine aerobic capacity for the structural firefighter. This protocol is heart rate, blood pressure and WFI (body composition measurement). Even with WFI added, it is still the Gerkin Protocol. Body composition is computation and not actual in that the only accurate way of measuring body fat is hydrostatic weighing (water immersion and water displacement). Electrical impedance or calipers are estimations so therefore, aerobic capacity is never exact, except by hydrostatic weighing first.
Research and education are essential to cut through this verbiage and understand what is academically and medically verifiable.
The question still remains for each department as to whether the department wants a medically verifiable physical examination and health enhancement program, or whether the department is only interested in the physician clearance form for their files.
What is the program in your department or are you going to take offense when you are told hand grip strength is not health screening? Or when you are not doing the blood work for gout, which is a debilitating disease for a firefighter, and/or thyroid testing or testing for adult onset diabetes.
Health comes first, then fitness. “If you can get healthy, you can get fit.”
The last item to be considered is the credentials of those performing your physical examinations. Ask the questions — are they ACLS (Advanced Cardiac Life Support) certified? This also applies to the physician if there is one on site for the testing.
Charles F. Turner, R.N. is President/Director and founder of North Greenville Fitness and Cardiac Rehabilitation Clinic. Since 1979 he has performed over 120,000 Stress Tests and Health Screenings. He can be reached at 888-348-8911.