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Is there a special dread about 35? Well, Jimmy Stewart had claimed in speaking to his Doctor, “I’ve wrestled with reality for 35 years, Doc, and I’m happy to say I finally won out over it.” Many of us might agree that going over and beyond age 35 is something we wish was not a reality! But is it the same with the mysterious acronym, BMI? BMI for many is something to truly wrestle with, if it is indeed over 35.

BMI Spelled Out

Some of you are in the know about BMI, and others have no idea, or would take a stab at what makes sense that BMI stands for…Brain Machine Interface, Masters of Business Imagination, for the burger lovers there has been Big Mac Index, and actual registered slang online reveals Bad Mental Image and Barely Makin It. Barely Makin It could in fact be a stand in for BMI over 35, and how is that so?

BMI really stands for Body Mass Index. It is a measurement used as a way to find out if your weight signifies you have a health risk. This tool attempts to measure your amount of tissue mass which is combined muscle, fat and bones. So it measures this by taking a person’s weight in kilograms divided by the square of height in meters.

High BMI can Make You Feel Low!

Research studies have confirmed that higher levels of body fat make people at risk for many diseases, including heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems and cancers. BMI has been a tool used by health professionals worldwide, to indicate risks.

BMI does not measure body fat directly, but research has shown a positive correlation of BMI compared to actual direct measures of body fat from more complex tools including: skin fold thickness measurements, bioelectrical impedance, densitometry, dual energy x-ray absorptiometry and other methods. BMI, obviously is a quick, inexpensive, and simple early screening for obesity.

Do the Math

Even if you don’t know the metric system, the formula if not calculated by yourself, can be easily obtained on charts online. For example, check here

Or, you can just change the metric to English with this calculation: pounds multiplied by 703, divided by height in inches, squared.

BMI = (weight in pounds) x 703/2

(height in inches)

For example, if your weight is 100lbs, and your height it 5’6″ this is the calculation:

BMI= 100 x 703 = 70300 = 70300 = 16.14


66 66 x 66 4356

which in BMI on the chart is an underweight person!

So, what do the charts show after you do the calculation, or check out your scores online?

Generally, a BMI of less than 18.5kg/m2 shows a person who is most likely underweight.

A BMI of 19-24.9kg/m2 is generally considered a healthy weight

A BMI of 25-29kg/m2 is determined as overweight with recommendations to lose weight for better health

A BMI over 30kg/m2 is marked as fat or obesity, and means you have a health risk and it is important to lose weight for your health

A BMI of 35-49 is considered severe obesity

A BMI over 40 is considered morbid obesity

Some research estimates have shown that a BMI of 30 and over increases the risk of death from any cause by 50 to 150 percent.

Heavy Concerns

Obesity has been a growing (pardon the pun) concern. In 1994 the US national health and nutrition examination showed that 59% of men and 49% women had BMI’s over 25, and BMI of 40 or more in 2% of men and 4% women. Remember a BMI of 35 and over is now considered overweight. A 2007 survey showed 63% of Americans are overweight or obese. In 2008 a study found that obesity defined by BMI at or over 30 was in 21% of men and 31% of women.

The determinations of the BMI itself have changed over the recent past. In 1980 overweight was a BMI of 24.9 to 27.1. In 1998 the Federal government was responsible for new guidelines for healthy weight, and their determination was a BMI over 25 is overweight and a BMI over 30 is obese.

Medical professionals consider that if a person falls into the BMI range of 25 to 35.9 and has a waist size of over 40 inches for men and 35 inches for women, this is considered a great health risk.

The Measurement Debates

The reason why waist size is also considered a part of weight determination along with BMI is that there is much debate over the accuracy of BMI alone. Since muscle weighs more than fat, heavy muscle will weigh more and cause a higher BMI calculation than fat. A person who is muscular, may have a high BMI, but be in great shape!

Older people usually lose muscle, so in older people body fat in relation to the loss of muscle weight can also lead to an underestimation in a BMI calculation.

weight loss

Since many studies, research has indicated the significance of fat around the waist rather than hips as a higher risk for heart disease and type 2 diabetes, waist circumference is another valued measurement. Sometimes you see this as referred to as abdominal fat, or belly fat. The risk goes up with waist size that is greater than 35 inches for woman and greater than 40 inches for men. Many professionals describe obesity as those people with a waist circumference that is greater than 50% of their height. A high waist circumference has been determined to be a risk for type 2 diabetes, dyslipidemia, hypertension and cardiovascular disease.

A waist measurement uses a tape measure and measures just above your hipbones after you breathe out.

Professionals prefer to consider both BMI scores and waist circumference measurements to determine health risk and obesity related conditions.

The BMI Curve Beginnings

The scale was developed by Adolph Quelet in the 1800s who was a Belgian astronomer. He was working on statistics related to stars using army information of weights and heights. His discovery that there was a bell curve of weight distribution around height, that led him to conclude that the top of the curve was a normal weight and those who deviated from it were over or under weight.

Following this, an insurance company employee, Louis Dublin, wanted to find a good way to determine his company’s life insurance claims and risk, and found that thinner people lived longer, and the more a person’s weight was similar to a 25-year-old, the longer they lived. He then figured out a weight range for living the longest. Doctors took this calculated information and began to determine overweight and how weight predicted health risks.

BMI and Sleep Apnea

Besides for type 2 diabetes, heart disease, and cancer risks of a high BMI, research has shown a significant relationship with the severity of obstructive sleep apnea in obese people. A study conducted by doctors with the St. Luke’s hospital in New York found that BMI has significant positive correlations with apnea the hypopnea index in obese diabetes patients. In yet another study, researchers found that in patients with a mean BMI of more than 25 kg/m2, there was a significant trend in the relation of total body fat in predicting obstructive sleep apnea severity. The researchers counseled that doctors who treat obese patients should also consider they may be suffering with undiagnosed obstructive sleep apnea.

In another study called sleep AHEAD, patients with diabetes and obstructive sleep apnea were also assessed for any long-term effect of weight loss, and the positive news is, that overall fat loss carried a significant improvement in sleep disordered breathing.

BMI and Aviation

Very recently in February 2015, the FAA issued a guidance to aviation medical examiners regarding denials, deferrals and special issuance for obstructive sleep apnea which was related to BMI scores. This was because in November of 2013, the FAA had proposed to aviation medical examiners to ground pilots with a BMI of 40 or more until they completed treatment and received a special medical certification. The FAA believed that OSA is almost always found in obese people with a BMI over 40 and a neck circumference of 17 inches or more. Since then aviation medical examiners have been looking at signs or symptoms of sleep disorders, which could be signs of problems that interfere with normal sleep which pilots need to safely perform their job.

It is a comfort to know that the American medical examiners for airman qualifications and requirements have gotten strict related to obesity and related sleep disorders from BMI assessments. But this type of qualifying need not be restricted to pilots, as everyone, no matter the occupations, is probably at a health risk with a BMI over 35, and most probably according to research, also suffering from sleep apnea.

Tips and Takeaways

  • BMI can be a useful method to determine obesity
  • A BMI over 35 is indicative of obesity in most cases
  • Obesity has many health risks, and people with BMI over 35 are at greater risk of diabetes and heart disease
  • There is a definite link between obesity and sleep apnea
  • People with BMIs over 35 are the most likely to be suffering from sleep apnea
  • The link between obesity and sleep apnea is so strong, the FAA has recommended grounding pilots with BMIs of 40 or more, due to safety concerns

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