Monday, September 12, 2011

Waist-Hip Ratio or BMI?

Definition

Waist-hip ratio can be defined as the ratio between the circumferences of waist to the hips. How to measure. The waist circumference should be measured at the narrowest point of waist that is usually midway between the lowest rib and iliac crest. The hip circumference should be measured at the broadest area of hips with legs close together. The waist-hip ratio can be calculated by dividing the waist circumference by the hip circumference.Indicator of health. The Waist to hip ratio can be used as an indicator to measure of the health of a person, and to calculate the risk of developing health conditions. Apple-shaped bodies (people with more weight around the waist) suffer more health problems than those with "pear-shaped" bodies (people carry more weight around the hips).

Waist to hip ratio is used as a measurement of obesity. Which is an indicator of other more serious health conditions? A Waist hip ratio of 0.7 for women and 0.9 for men is shown to correlate strongly with health and fertility. Women within the 0.7 range do have optimal levels of estrogen and less susceptible to diseases such as diabetes, CVS disorders and ovarian cancers. Men with Waist hip ratio around 0.9 have been shown to be more fertile and healthy. Waist hip ratio has been found to be an efficient predictor of mortality in elderly people than body mass index.

If obesity is redefined using Waist hip ratio instead of BMI, the percentage of people categorized at risk of heart attack worldwide would increases threefold. The body fat percentage is also considered to be an accurate measure of relative weight... Hence, it is possible that two women have different body mass indices but same waist-hip ratio, or they have the same body mass index but different waist-hip ratios. Even in ancient civilizations, female representations are most often in the 0.6-0.7 range for waist hip ratio, suggesting a preference towards lower Waist to hip ratio. Other studies have found that waist circumference, not waist hip ratio, to be a very good indicator of CVS risk factors, body fat distribution, and hypertension in type 2 diabetes. Body Mass Index (BMI)

BMI metric units:

• Weight in kilograms divided by the square of height in meters for example. If Weight 80 kilograms and Height is 1.8 meters.so 1.82 meters square = 3.24 then 80 divided by 3.24 = BMI 24.69.

Imperial units:

• Weight in pounds multiplied by 703, divided by the square of height in inches. For example. If Weight is 190 pounds. and Height is 6 ft or 72 inches square of 72 = 5184 and 190 x 703 divided by 5184 = BMI 25.76

It is mostly agreed that: People with BMI below18.5 is underweight, between 18.5 and 25 is ideal, between 25 and 30 is overweight and over 30 is obese.

In some countries health officials say the lower limit for BMI is 20, and anything below is underweight.

Problems with BMI.

BMI is a very simple tool which does not account for the person's waist, chest or hip size. A weight lifter could have a higher BMI as compared to a person with a large belly due to large muscle mass but it does not mean that he is over weight or obese. It is just due to the over simplified calculations of BMI which does not account for fat to muscle ratio. Also BMI does not account for bone mass.

So that is why many health professional do not take BMI as a good tool for ideal body weight calculation. They take this tool as a general measure for rough estimations or simple BMI underestimates body fat in obese people and overestimates it in muscular or lean people.

Summary

So as a whole if we compare the two BMI and Waist hip ratio we find out that BMI is a rather very simple tool that was easy to use and easy to apply in lot of situations. but today as we know WHR is a better option that gives us a better understanding about the general health conditions of the person and its overall health out look. another obesity analyzer is body fat percentage which is even more accurate but is rather a bit difficult to calculate and only experts can handle it better.


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