BMI: Everything You Need to Know About Body Mass Index
BMI is a widely employed and deeply flawed metric to gauge ones physiological health. This is what you need to know about it, as well as several practical and superior alternatives.
Clinical obesity represents a growing cause for concern in the U.S., the developed world, and beyond. Now, in America specifically, childhood obesity is being diagnosed with alarming frequency. One tool heavily relied upon by doctors to determine if a patient qualifies as overweight or obese by clinical standards is the Body Mass Index or BMI. However, this simple calculation which has become a cornerstone in determining one’s health just might be cracked with new research showing the unreliability of this pervasive measurement. Meanwhile, superior measurements exist that provide a more precise description of body fat content and thus a more accurate overall sense of a patient’s degree of obesity.
The Intricacies of BMI
Since the index’s publication in 1972, the BMI has been used to measure body fat and overall health in an individual. Its popularity has much to do with ease of use and cost effectiveness. If you question the measurement’s actual significance outside the doctor’s office, know that BMI has been utilized by U.S. employers to provide financial incentives for employees to lower their BMI. This is because one’s weight issues or propensity for health complications are considered by health insurance companies. Poor health means more doctor visits; the more one visits a clinic or doctor’s office the more their health insurance provider must pay.
BMI is determined by two factors, an individual’s height and weight. To calculate it, one must divide their weight in kilograms (kg) by the square of their height in meters (m²). If this jargon seems a bit confusing, just take your height and weight and convert your recorded measurements to the units just mentioned.
BMI is a calculation known for dividing people into one of four categories: Those with a score less than 18.5 are classified as underweight, a score between 18.5 and 24.9 is considered normal or healthy weight, a score of 25 to 29.9 is considered overweight, in contrast to people with a score of 30 or greater that are deemed obese.
It’s important to note, however, that basing one’s health on their height and weight alone fails to account for body’s bone, muscle, or fat proportions. Muscle, for example, is a tricky topic. An individual who is particularly muscular with a very small percentage of body fat and a BMI between 25 and 30 is likely to be considered overweight. This is almost certainly the case for many professional football players. Nevertheless, that’s not an accurate assessment of the individual’s health status.
Lean muscle, or muscle that is independent of, as well as not covered by, fat and fat itself weighs the same pound for pound. Their composition, on the other hand, greatly differs. According to the personal health columnist for The New York Times Jane E. Brody, fat takes up around “four times the space of muscle tissue” (para. 4). This makes muscle about four times as dense, or thick, as fat tissue.
It’s because of body composition nuances such as this that BMI runs into a little bit of trouble.
BMI’s Accuracy and Reliability
In a 2016 paper published in the International Journal of Obesity, A. Janet Tomiyama et al. from the University of California, Los Angeles (UCLA), identified BMI as a flawed approach to determining one’s health status.The paper cited a study also conducted by Tomiyama et al. assessed 40,420 individuals, aged 18 and above, who were a part of the 2005 to 2012 National Health and Nutrition Examination Survey (NHANES). It’s important to note that this survey at the time contained “nationally representative prevalence data on cardiometabolic health.”
The study found that around 29 percent of individuals classified as obese, and even about 16 percent of those said to have type 2 or 3 diabetes were cardiometabolically healthy. On the other hand, over 30 percent of individuals said to be normal weight or healthy were cardiometabolically unhealthy. Talk about a dramatic twist!
Additionally, Medical Daily writer Jalessa Baulkman stated that using BMI to gauge health has led to over 54 million Americans being misclassified as unhealthy. It’s because of this that Tomiyama and company (2016) suggested that policymakers consider the consequences of relying solely on this measurement.
The same goes for employers and physicians as well. Ultimately, BMI should be used as a screening tool when trying to determine body fatness, but not as a definitive diagnostic tool for actual health. Since obesity is an ever-increasing health concern, it’s still important that individuals and health professionals correctly measure a patient’s body fat.
In light of the established inadequacies inherent to BMI, what are more accurate metrics to gauge obesity? Below are some alternatives that can be used to more accurately determine overall body fat composition and health status in an individual.
Alternatives to BMI
A waist circumference, or the distance around your waist, that equals half your actual height can be one indication of good health, as this measurement can be an indication of excess abdominal fat. For example, if you happen to be five foot, eight inches tall (68 inches), then having a waist circumference of 34 inches or smaller would be considered healthy.
According to the Centers for Disease Control and Prevention, excessive abdominal fat is potentially dangerous because it places one at greater risk for developing high blood pressure, Type II Diabetes, and coronary artery disease. To determine waist circumference, one must stand straight and wrap a tape measure around their mid-section.
The tape measure should be just above one’s hip bones and along the belly button. The person being evaluated should not suck in their gut during this process. Furthermore, taking the average of about three different measurements should give you a pretty reliable number.
A skin caliper is a device pulls subcutaneous fat, or fat that lies directly under the skin, away from muscle through use of tongs situated at their ends. A skin-fold assessment can be completed using several different parts of one’s body, such as the abdominals, back, thighs, chest, and arms. An equation is used to determine body-fat percentage from the recorded measurements. It’s important that a practicing professional conduct this test to produce more accurate results.
This method is also referred to as “underwater weighing.” According to exercise physiologist and fitness consultant Elizabeth Quinn, this method determines one’s “total body density using Archimedes’ Principle of displacement” (Quinn, 2017, para. 1). Hydrostatic weighing works by comparing a person’s normal body weight on dry land to their body weight when completely submerged in a large tank of water. Accordingly, hydrostatic weighing is one of the most accurate assessments of body fat composition with a very small margin of error. As a result, it’s considered the gold standard for body composition assessment.
Bioelectrical Impedance Analysis
This method measures body composition by sending an electrical current through the body. The faster the current, the less body fat an individual has. Body fat, or adipose tissue, causes greater resistance for an electrical current than fat-free mass, and therefore slows the rate at which the current travels. Bioelectrical Impedance Analysis has been shown to be fairly accurate when estimating body fat.
Air Displacement Plethysmography
Like underwater weighing, air displacement plethysmography, also known as BOD POD, follows a similar technique except with air. As a result, this method has gained popularity among body composition researchers due to the non-invasive test-procedure as well as the lack of technical expertise required. Researchers David A. Fields, Paul B. Higgins, and Gary R. Hunter have described the BOD POD as “a single fiberglass unit composed of two chambers” (p. 1).
The test chamber accommodates an individual during testing while the reference chamber contains instrumentation that measures “changes in pressure between the two chambers” (p. 1). Therefore body composition is essentially calculated by measuring the amount of air before and after an individual enters the BOD POD along with the density of air.
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Dual Energy X-Ray Absorptiometry
Also referred to as “bone densitometry,” this method produces pictures of a person’s body internally by using a very small dose of ionizing radiation. Dual energy x-ray absorptiometry measures lean body mass, fat mass, and bone mineral density. Through this method, technicians can determine the breakdown of body composition for each section of one’s body.
While the public perception of the desirable body size may have shifted to be more diverse and has started to include more plus-sized physiques, being clinically overweight or obese can still lead to major health complications. Positive body image aside, having an excess of body fat may cause issues such as high blood pressure, diabetes, and heart disease. The best thing one can do is determine if their unique physique is, in fact, conducive to good health. Fortunately their are many tools other than the potentially misleading BMI that can be used to answer that question.
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Baulkman, J. (2016, February 06). Normal Body Mass Index Doesn’t Mean You’re Healthy, Study Says; Millions Of Americans Mislabeled As Obese. Retrieved March 17, 2018, from http://www.medicaldaily.com/body-mass-index-obesity-america-372526
Brody, J. E. (2010, August 31). Weight Index Doesn’t Tell the Whole Truth. Retrieved March 16, 2018, from http://www.nytimes.com/2010/08/31/health/31brod.html
Fields, D. A., Higgins, P. B., & Hunter, G. R. (2004). Assessment of body composition by air-displacement plethysmography: influence of body temperature and moisture. Dynamic Medicine, 3(1), 3.
Quinn, E. (2017, November 30). How to Measure Body Fat With Hydrostatic Underwater Weighing. Retrieved March 17, 2018, from https://www.verywellfit.com/what-is-hydrostatic-underwater-weighing-3120276
Tomiyama, A. J., Hunger, J. M., Nguyen-Cuu, J., & Wells, C. (2016). Misclassification of cardiometabolic health when using body mass index categories in NHANES 2005–2012. International Journal of Obesity, 40(5), 883.
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Is Running on Pavement Safe? The Fitness Facts
Master Trainer Jared Stokes weighs in with his expert insight into the timeless fitness question, “Is running on pavement safe?” Jared Stokes is a health and fitness professional with a EdD. in Health Education from Columbia University in New York City, in addition to his extensive personal training experience. Today Mr. Stokes gives the hard facts on this longtime fitness quandary, and how you can minimize the risk of injury.
At some point in our lives we’ve all witnessed the dedicated runner, making their way along a sidewalk or street where a path has been created for their safety. While it is certainly commendable that an individual decides to run outdoors, thus remaining physically active and presumably healthy, one must ask, “Is running on pavement good for one’s joints?” One could assume the answer is no, since pavement is “rock-like” and probably doesn’t give when one exerts force on it. Nevertheless, people continue to run. Here, we will tackle the actual risks, or non-risks, associated with running on pavement.
Pavement: Asphalt vs. Concrete Difference
For the benefit of clarity, pavement is defined here as asphalt. Asphalt is reportedly the most recycled material in America, and is often used on city streets, park trails, or sidewalks. This is not to be confused with concrete, which is made by mixing a cement binder with an aggregate material and then letting the mixture harden, which forms a rock-like substance.
Asphalt, on the other hand, is made by mixing an aggregate with bitumen, which is a sticky black hydrocarbon extracted from crude oil. Columnist Trent Jonas (2017) advises runners to avoid concrete whenever possible.4
Is Running on Pavement Safe? The Brass Tacks
Getting down to brass tacks, let’s explore the safety of running on asphalt pavement. According to popular running guru Erin Beresini (2013), data on this debate is mixed.1 As mentioned, many believe that certain running surfaces can lead to injury, but this is a long time debate among fitness experts.
Certain experts seemingly point to myriad additional factors involved. For example, a study led by Dr. Ida Buist (2010) of University Medical Center Groningen, Netherlands, observed gender-specific predictors of running-related injuries (RRIs) in inexperienced “runners training for a 4-mile distance run.”2
The results of this study found that for men Body Mass Index (BMI), having participating in sports without axial loading prior to the study, and having previous musculoskeletal injury of the lower limbs or back were significant predictors of RRI. For women, navicular drop was the only significant predictor of RRI the study found. It should be noted, however, the running surface was not assessed in this study.
In Trent Jonas’ (2013) view, he concluded that asphalt is associated with the lowest amount of shock forces exhibited on a runners body, or minimal impact on one’s locomotor system.4 Jonas (2013) furthermore asserted that asphalt is the best running surface when compared with cement and grass, although gravel might be a better option overall.4 Beresini (2013) purported that runners should consider mixing up their running surfaces to minimize possible injury.1
All in all, the debate continues pressing onwards.
Proper Distance Running Technique
One thing is for certain: the way one runs and their running equipment are critical factors to consider. First, let’s address the way one runs, or running technique. Moore (2016) looked at biomechanical factors that affect running economy, or the rate of oxygen one’s intakes at a given submaximal running pace.
Results showed that biomechanical factors effecting so-called running economy included “spatiotemporal factors, lower limb kinematics, kinetics, neuromuscular factors, shoe–surface interactions, and trunk and upper limb biomechanics” (Moore, 2016, p. 803). In laymen English, this study proved that runners should be highly conscious of their running form. Here is the overall best approach to perfect your running technique.
Techniques for running form include the following:
- Have proper posture when running – that means back straight up!
- Keep your feet pointed straight ahead rather than to the side.
- Land midfoot rather than on your heel.
- Look upwards and ahead.
- Relax your hands and shoulders.
- Keep your arms at your sides.
- Don’t bounce as you run.
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Proper Running Shoes: Beginning at the Point of Contact
Last – but hardly least – runners should put considerable effort finding the proper equipment when deciding to run, namely running shoes. A study by Kathleen O’Leary et. al (2008) found that “the use of cushioned insoles during running resulted in significant reductions in mean vertical ground reaction force peak impact and loading rate, as well as peak tibial acceleration.”5 Dale (2017) also supported the idea of finding shoes with extra padding when running on pavement. Moreover, one should make sure that their shoe has the proper fit.
These may appear like common sense, no-brainer suggestions. Though many runners, or aspiring runners, do not always take the proper time and effort to implement these required preparations for their run. The devil is perpetually in the details, and running is no different.
Is Running on Pavement Safe? Common Sense and Good Information Is Key
In total, the risks of running on pavement is a complex topic and activity, one that all runners must invest time and energy to perfect. It is clear that there are certain risks that come with road running on pavement, however those risks can be mitigated with proper technique, equipment, and most importantly common sense. Have you suffered previous lower limb or back injury? Have you invested in high quality running shoes? Do you employ proper technique? Have you sought out the advice of a credible personal trainer? These are the questions runners – or aspiring runners – must ask themselves. However like all good exercise of choice, it requires the dedication of the individual to find good information to achieve their desired goal.
Do you have any fitness questions for Master Trainer Stokes? E-mail him at email@example.com
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1 – Beresini, E. (2013, October 06). The Best Running Surface for Your Knees. Retrieved January 24, 2018, from https://www.outsideonline.com/1784266/best-running-surface-your-knees
2 – Buist, I., Bredeweg, S. W., Lemmink, K. A., Van Mechelen, W., & Diercks, R. L. (2010). Predictors of running-related injuries in novice runners enrolled in a systematic training program.
3 – The American journal of sports medicine, 38(2), 273-280.
4 – Jonas, T. (2017, September 11). Running on Cement, Asphalt & Grass. Retrieved January 24, 2018, from https://www.livestrong.com/article/530023-running-on-cement-asphalt-grass/
5 – O’Leary, K., Vorpahl, K. A., & Heiderscheit, B. (2008). Effect of cushioned insoles on impact forces during running. Journal of the American Podiatric Medical Association, 98(1), 36-41.
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5 Things All Women Should Know Before Trying A Waist Trainer
Those who buy and use waist trainers may get more than they bargained for, and far less than they paid for.
Today TGNR introduces Health and Fitness Contributor, Master Personal Fitness Trainer Jared Stokes. Mr. Stokes is a long practicing personal fitness trainer, and is currently completing his Ph.D. thesis in Heath Sciences at Columbia University, in New York City. He is also author of the newly released,. “Pathway to Heaven,” the first installation of The Red Series As well as serving as a founding member and leader of K3mistry Productions; a multifaceted company dedicated in part to providing sound fitness information, and introducing exercise to new people in a uniquely positive paradigm. Today, Mr. Stokes delves into one of the hottest modern fitness trends – the Waist Trainer.
As TGNR’s mission is reporting fascinating good news, the topic of positive and accurate public heath information is of great concern. Mr. Stokes today shares his expert insight on 5 things all women should know before trying a waist trainer.
America has witnessed many trends come and go, like tether ball or a German Shepard playing a game of “fetch the Frisbee.” From Disco Pants to Colombian jeans, every fad has its time to shine before fading off into the distance. Alas, it is now 2015 and a new development has taken the country by storm, or rather by the belt buckle. Its name, ladies and gentleman, is waist-training…
5: What Does A Waist Trainer Aim To Do?
Our culprit here includes such waist trainer entities as Miss Belt or Gennie Hourglass, both of which act as a modern day corset. According to writer Jamie Harrison, in an article for Ebony Magazine entitled “Getting Waisted: The Dangers of Corset Training,” : waist-training is considered a practice aimed at reshaping women’s bodies, and trimming inches off their waists through use of a 21st century steel-boned corset, and doing so by being worn for a certain amount of time each day. Ain’t that a mouthful?
Basically, the practice much like its predecessor of the Victorian era, is meant to help women obtain the classic hourglass figure. A look usually defined as having ample breasts, a flat stomach, and voluptuous buttocks. Molly Shea, Assistant Editor for Yahoo! Health states that waist-training at first, “seemed like the kind of trend that would fizzle out quickly.” This assumption was plausible, considering the fact that corsets are extremely outdated. However, thanks to support from celebrities such as Kim Kardashian, Jessica Alba, and Brooke Burke-Charvet this trend may be here to stay for a little while.
So, what are the proven effects the body experiences when wearing a waist trainer during your workout?
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Life Growing Up With Autism: First Hand
In this edition of Beyond the Puzzle Piece, I introduce you to Christopher Jones. Christopher is an 18 year old math enthusiast, with an interest in history and politics as well. Chris also has a unique experience and voice when it comes to Autism Spectrum Disorders. Following an initial diagnosis with Asperger Syndrome at the age of 4, Chris has received Special Education services since that time. He was part of the first wave of students with what is called “High Functioning Autism” to go through the educational system while receiving services specifically for his needs. Chris has received Physical and Occupational Therapy to help cope with sensory issues, as well as Speech and Language Therapy and Social Skills groups to assist in communication skills. He started in a self contained Autism Support Classroom with a dedicated Special Education Teacher, and was gradually included further into the general education classroom. Now 18, Chris is a High School Senior with very strong opinions about everything from music to politics, and certainly autism. Join my conversation with Christopher as he shares with TGNR the thoughts, experiences, informed views, and reflections of his life with autism.
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