Waist circumference and waist-to-hip (WHR) ratio are two important measurements that help determine a person's overall health. Measuring the circumference of the waist and comparing it with the hip measurement can provide a good indication of increased risk for obesity-related diseases such as diabetes and cardiovascular disease.
Obesity is a medical condition in which an excess of fat accumulates in the human body. It is associated with increased risk of illness, disability, and premature death. Medical professionals generally consider obesity, or excessive overweight, to be a chronic illness that is often grouped with other chronic conditions such as high blood pressure and diabetes, which can be controlled but not presently cured.
Good ways to control obesity and thus decrease waist circumference and WHR ratio are to maintain a healthy body weight by eating modest proportions of balanced and nutritious foods and exercising on a regular basis.
The purpose of these measurements is to help to determine the overall distribution of fat on the human body. Although all obesity can increase risk of disease, having a higher amount of fat at and above the waistline increases the risks of heart disease, type 2 diabetes, some cancer, and death, even more than overall weight gain.
Excessive values for waist circumference and WHR ratio have become much more common in Western society as more people become overweight or obese. Being overweight has become a serious public health problem that affects both sexes and all ethnic, racial, age, and socioeconomic groups in the United States and around the world. More than two-thirds (nearly 70%) of American adults are considered overweight or obese. As people age, fat is more likely to accumulate in the abdomen, or belly. More than 50% of men and 70% of women have abdominal obesity, meaning the ratio of their waist circumference to their hips is high.
The waist is defined as the part of the abdomen between the lowest rib and the upper portion of the hips. Circumference is defined as the distance around an object. For instance, the circumference of a circle is the distance around the outside edge of the geometric figure. Waist circumference refers to the distance around the waist of a person. It is determined with a common measuring tape (a tape measure), which is a flexible type of a ruler. A measuring tape can determine the circumference of the waist by placing the tape at or around the navel (belly button).
The waist is usually measured at the smallest circumference. For people of normal weight, the waist is usually just above the navel. This horizontal circle where the waist is the narrowest is generally called the waistline. For pregnant women or overweight or obese individuals, the waist is usually measured one inch above the navel. It is helpful to measure the waist while standing and just after exhaling (breathing out).
The waist circumference is an important measure for determining obesity-related diseases such as heart disease and diabetes. People with excessive weight around their waists are at greater risk for such diseases.
The hip, medically called the coax, is the anatomical region on each side of the human body located between the waist and the thigh, and is a projection of the pelvis and upper thighbone on each side of the human body. The WHR, or sometimes called the waist-hip ratio, is the ratio of the circumference of the waist to that of the hips.
Under most circumstances, the circumference of the waist is measured at the smallest circumference of the waist, but the circumference of the hip is usually measured at the widest part. As with the waist circumference measurement, the hip circumference is also determined with a tape measure.
For instance, a woman might state that her measurements are 36-29-38. This group of three dimensions means this woman has a circumference around her bust, a measurement of the upper rib cage and the breasts, of 36 in. (approximately 91.4 cm), a circumference around her waist of 29 in. (approximately 73.7 cm), and a circumference around her hips of 38 in. (approximately 96.5 cm). Therefore, her WHR ratio is 29 inches divided by 38 inches, or WHR = W/H, equaling approximately 0.76.
It is best to use a tape measure intended for tailoring or dressmaking. These tapes are made from flexible cloth, plastic, or fiberglass. The tape is marked with numbers representing inches or centimeters, beginning at zero and ending at a positive number (the length of the tape). For measuring waist circumference and WHR ratio, the tape should be snuggly wrapped around the portion of the torso that a person wants to measure. The beginning of the tape (the zero mark) will align with one of the larger markings on the tape. This particular marking is the circumference.
The waist circumference measurement is used as an indicator of possible health risks associated with being overweight or obese. It indicates the increased risk of more serious medical problems such as type 2 diabetes, kidney disease, cardiovascular disease, and some cancers. If more fat is distributed around the waist than around the hips, a person is at higher risk for these obesity-related medical conditions than if the circumference of waist was smaller than the hips.
In many ways, simply measuring waist circumference is enough to indicate if an individual is likely to have health risks. The National, Heart, Lung and Blood Institute (NHLBI) states that if men have a waist circumference greater than 40 in (102 cm) and women have a waist circumference greater than 35 in (88 cm), they have an increased risk for obesity-related diseases.
The WHR can help indicate disease risk, but it is less important in overweight and obese people than a simple waist measurement. A waist-to-hip ratio of 0.7 or less for women and a WHR of 0.9 or less for men is generally considered to be healthy.
When a person is overweight or obese, the risk for heart disease and many other conditions increases. Being obese and having an extremely high waist circumference is one of the strongest indicators of having or developing obesity-related diseases. Other factors can increase that risk even more. These factors, according to the NHLBI, include:
To maintain a healthy lifestyle, weight circumference should be less than 40 in. (102 cm) for men and less than 35 in. (88 cm) for women. The primary way for achieving and maintaining a healthy body weight is a lifelong commitment to sensible eating habits and regular exercise. Even a weight loss as small as 5%–10% percent of one's current weight will help lower an individual's risk of developing obesity-related diseases.
See also Cardiovascular disease ; Cholestrol ; Hypertension ; Obesity .
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William A. Atkins, BB, BS, MBA
Revised by Teresa G. Odle, BA, ELS