Scientists disagree on waist measure value - Air Force News | News from Afghanistan & Iraq - Air Force Times

Scientists disagree on waist measure value

It doesn’t make sense at first glance. How can a 6-foot-5-inch, 49-year-old master sergeant be expected to have the same 32-inch waist as a 5-foot-5-inch, 18-year-old airman?

But that’s the one-size-fits-all standard for the abdominal circumference portion of the Air Force fitness test. Better known as the waist measurement, it determines up to 30 out of a possible 100 points on the physical training test. Airmen with more than a 32-inch waist — 29 for women — have to go through extra hoops if they hope to ace the PT Test.

Yet the strict waist-size limits do not account for height, age or any other factor, puzzling many airmen and some scientists.

“Everybody has different body shapes, and not everyone can have that 32-inch waist,” said Staff Sgt. Jeremy Young, a physical training leader at Mountain Home Air Force Base, Idaho.

Steve Farrell, a director at the Cooper Institute — which helps train the Air Force’s fitness leaders — agreed with Young, and also questioned why the waist measurement isn’t scaled for age, like the rest of the test, which includes a 1.5-mile run, worth 50 points; and push-ups and sit-ups, worth 10 points each.

“The Air Force makes allowances with the aging process for strength and cardiovascular fitness levels to decline, and it’s normal for entering the aging process,” Farrell said. “Cardiovascular fitness declines, strength declines; so why should someone be expected to keep the same waist circumference when we know that when the aging process occurs, that body fat goes up, and yet there is no allowance for that?”

The Air Force is the only service to use the waist measurement in its PT test. The other services tape the neck, chest and waist, and use height and weight measurements to calculate body fat percentage, which is scaled by age.

Even the Air Force Academy forgoes the waist measurement for the physical training tests cadets take each semester until their senior year, when they are required to pass a standard Air Force fitness test.

Maj. Dana Whelan, chief of health promotion operations at the Air Force Medical Operations Agency, said the service kept height and age considerations out of the scoring for the waist measurement because neither height nor age should affect the size of an individual’s waist.

However, opinions on whether that’s true are mixed inside the scientific community.

The debate continues as the Air Force “investigates ways to modify the scoring system to incentivize maximal health and fitness” as service leaders consider overhauling the service’s fitness program, said Betty-Anne Mauger, a spokeswoman for the Air Force surgeon general.

Chief Master Sgt. of the Air Force Rodney McKinley is overseeing an overhaul of the service’s fitness program, and an announcement of changes is expected as early as this month.

Dympna Gallagher, director of the Human Body Composition Core Laboratory of the New York Obesity Research Center, and Dr. Charles Billington, co-director of the Minnesota Obesity Center, both agree with Air Force standards, saying that a person’s waist size should not be affected by height.

Farrell, as well as researchers at the American Journal of Preventive Medicine and the International Association for the Study of Obesity think the opposite is true — that height and/or age need to be taken into consideration in order to have a more accurate assessment of someone’s health in a body-composition calculation.

A study conducted at the Air Force Institute of Technology concluded in 2005 that the service was wrong to use waist measurements without accounting for height and should replace the criterion with waist-to-height ratio, which divides waist size by height. Scientists have found that a healthy individual’s waist-to-height ratio should be below 0.5, said Steven J. Swiderski, a former Army emergency medical technician and Air Force finance officer who did the study.

In 2004, when the Air Force added the waist measurement to its PT test as part of the new “Fit to Fight” fitness program, service leaders boasted that the waist measurement was “based on the best science available.”

“It’s more of a health-based standard,” said Maj. Lisa Schmidt, then chief of promotion operations for the Air Force surgeon general’s office.

The Air Force can provide a list of 23 medical reports explaining why a waist measurement is a good indicator of an individual’s health. According to many obesity scientists, the science behind measuring the waist is sound.

Two types of fats exist in the human body — visceral fat located in the inner cavity around the organs, and subcutaneous fat found under the skin. Studies like the ones done by the American Journal of Clinical Nutrition and the American Institute for Cancer have found that individuals with excess visceral fat have increased chances of getting heart disease, diabetes and cancer.

Scientists found that a waist measurement has proven to be the best measure of visceral fat, Whelan said.

However, the waist measurement isn’t the only body composition test the Air Force performs. All airmen are weighed and measured to calculate their body mass index — an equation devised by the National Heart, Lung and Blood Institute that uses height and weight to provide one measure of a person’s healthy body range. A BMI over 25 is considered overweight and a BMI over 29.9 is considered obese, according to the institute. BMI is factored into PT test scores only when an airman has a BMI under 25. In that case, an airman whose waist measurement exceeds the Air Force standard can still earn the maximum 30 points.

But 55 percent of airmen have a BMI above 25, according to the Air Force surgeon general’s office. Other body composition calculations exist, such as the waist-to-hip ratio, neck circumference, body fat percentage and hydrostatic underwater weighing, which scientists such as Gallagher refer to as the “gold standard” of body composition measurement.

Yet such methods are not used because of accuracy or feasibility concerns. For example, the hydrostatic underwater weighing would be tough to implement across the Air Force because it requires submerging airmen in a pool, said Maj. Michael Brothers, director of the Air Force Academy’s Human Performance Laboratory.

Waist-to-height ratio

There is one body composition test that could replace the waist measurement, Swiderski concluded in his study: the waist-to-height ratio.

“The abdominal measurement is a ‘one-size-fits-all’ standard ... a person’s waist-to-height measurement ratio is a better measurement than the waist measurement to estimate an individual’s fitness level,” the report read.

To come to his conclusion, Swiderski took the PT test scores from all airmen at AFIT, including run times, sit-ups, push-ups and abdominal circumference, and factored in height and weight measurements. When he compared waist measurement with waist-to-height ratio, he found the waist-to-height ratio did a better job predicting who would have a lower run time, Swiderski said.

“AFIT statistically proved that one-size-fits-all isn’t a good standard,” he said.

In his report, Swiderski recommended a new scoring table for waist-to-height ratio that would make 0.460 the new standard — replacing the dreaded “32” or “29” among airmen.

Staff Sgt. James Baylis, a security forces airman at Travis Air Force Base, Calif., who graduated from Syracuse University with a degree in health and exercise science, said the whole debate over how to score a body composition test is misguided.

He argues that the 30-point maximum for the waist measurement should be cut and more points should be given for the push-up an sit-up portions of the test, which measure the muscles an airman would use in the field.

“If this is a fitness test, why aren’t you testing my fitness?” he asked.

DISCUSS: Waist measurement