In previous articles, we described how to assess your overall fitness status and how to develop a cardiorespiratory fitness program. You should now have a good idea of how physically fit you are and be on your way to living healthier. Now, let's focus on obesity and body fat in general a health issue facing a lot of people in EMS.
Many EMS personnel are required to complete a physical fitness assessment prior to being hired. For a good percentage of us, when we passed the physical exam we were in the best shape of our lives. But according to a 2007 report from the National Fire Protection Association, the leading cause of on-duty firefighter death is stress exertion usually resulting in cardiac arrest, heart attack or other cardiac emergencies. And many EMTs and paramedics are under similar levels of stress exertion.
Measuring Your Body Composition
Approximately 65% of Americans are overweightƒdefined as a body mass index (BMI) of > 25 kg/m. And about 30% are classified as clinically obeseƒdefined as a BMI of > 30 kg/m. However, BMIs can be misleading. BMI is not a measure of body composition; it's a measure of height and weight. So if you're muscular and lean, you may be above the desired range for BMI but not need to lose weight. For the majority of the population with high BMI measurements, though, it's usually due to fat, not muscle.
Thus, weight loss should be dictated by nothing more than body composition. Men should be between about 10Ï20% body fat, and women between about 20-30% for optimal performance and health maintenance. If your body composition is below the recommended range, you do not need to lose fat. In fact, you would need to gain the fat required for everyday bodily functions. Your local YMCA, college or fitness center will have someone qualified to measure your body fat percentage, and it's worth the effort to meet with a professional and establish baseline data that can be tracked over time.
If you find out you're above the recommended range, you can determine your ideal body weight by doing a few simple calculations:
Total Body Fat (TBF) = body weight x % body fat/100
Fat Free Body Weight (FFBW) = body weight - total body fat
Ideal Fraction (IF) = (100 - ideal body fat %)/100
Ideal Body Weight (IBW) = Fat Free Body Weight/Ideal Fraction
For example, if Sheila, who has a current body weight of 150 lbs. and body composition of 25% fat, wanted to trim down to 20% fat, her ideal body weight would be calculated as follows:
TBF = 150 x 25/100 = 37.5 lbs. of fat
FFBW = 150 - 37.5 = 112.5 lbs. of fat-free tissue
IF = (100 - 20)/100 = 0.80
IBW = 112.5 /0.80 = 140.6 lbs.
So for Sheila to meet her ideal body weight and body fat percentage, she would need to lose 9.4 lbs. (150 -140.6) of fat.
For Sheila, or any of us, to lose weight the right way, we need to understand calories and energy balance. Energy balance is a term used to describe energy intake, or the calories consumed in the diet. Energy expenditure is the number of calories burned in the course of daily activity. If energy intake exceeds energy expenditure, the excess will be stored as fat. Weight loss occurs whenever energy expenditure exceeds energy intake. One pound of fat has about 3,500 kcals, so if you expend 500 kcal/day below your caloric intake, creating a 500-calorie "deficit," it'll take about seven days to lose one pound of fat.
Proper weight loss should always combine calorie reduction with properly prescribed exercise. If weight loss occurs at a rate greater than two pounds per week, it's likely that some weight reduction will be from lost muscle tissue and/or water, which is not what we want. So be patient and smart about how you choose to lose weight.
In a sense, an effective plan for healthy weight loss won't include "dieting" in the typical sense of the word, but will include making healthy eating choices. We also need to keep in mind the importance of strength training. Don't get caught up in the misconception that cardiovascular exercise is the only method for controlling fat. Strength training will lead to increases in muscle mass, and muscle is the furnace that burns fat, even during rest. Extreme weight loss measures, on the other hand, actually cause a decrease in muscle mass a big no-no for long-term fat loss. Adding muscle will increase resting metabolic rate, which will make fat loss much easier and more efficient.
Now take Tyrone. His total bodyweight is 180 lbs., and his body composition is calculated to be 20% body fat through skin-fold measurements.
TBF = 180 x 20/100 = 36
FFBW = 180 - 36 = 144
IF (for 15% body fat) = (100 - 15)/100 = 0.85
IBW = 144 /0.85 = 169.4
Tyrone can stand to lose about 10 lbs. Following the recommendations above, he could take 10 weeks to lose this weight in fat. If all the weight lost was fat, his body fat percentage should decrease to 15%.
Losing, maintaining or gaining body weight is little more than a matter of arithmetic. If more calories are expended than consumed, weight is lost and vice versa. Exercise is a crucial component. Be smart about how you lose your weight, and read the next article on flexibility and its importance to your health. JEMS
1. American College of Sports Medicine: ACSM_s Guidelines for Exercise Testing and Prescription, 7th Edition. Lippincott, Williams & Wilkins: Baltimore, 2006.
2. Brzycki M: A Practical Approach to Strength Training. Masters Press: Indianapolis, 1995.
3. McArdle W, Katch F, Katch V: Exercise Physiology: Energy, Nutrition, and Human Performance. Lippincott, Williams & Wilkins: Baltimore, 1996.
4. National Fire Protection Association: "Firefighter Fatalities in the United States, 2008." www.nfpa.org/assets/files/PDF/osfff.pdf
5. Nieman D: Fitness and Sports Medicine: A Health-Related Approach. 3rd edition. Bull Publishing: Palo Alto, Calif., 1995.
6.Sattler T, Mullen J: The Fitness Handbook. 2nd edition. Sagamore Publishing: Champaign, Ill., 1995.
7. Sharkey B: Fitness & Health. 5th edition. Human Kinetics: Champaign, Ill., 2002.
What the Experts Say
The American College of Sports Medicine's recommendations for safe and effective weight-loss programs provide an excellent approach to losing fat. They recommend the following: