The body mass index or, as it was once called, the Quetelet index has become the de facto measurement for determining whether an individual is over – or under – weight. The formula is based on the weight and height of a person. Actually discovered in the 19th century by Belgian mathematician Adolphe Quetelet, the term ‘body mass index’ wasn’t coined until 1975 when the formula began seeing wide use. In today’s technologically advancing society there are differing BMI scale that measure and calculate – using programmed algorithms – an individual’s body mass index with surprising accuracy. The manufacturers of these products have taken Quetelet’s mid-1800s discovery, tossed in a few modern formulas and technology and then provide the user with increasingly accurate readings. However, to fully understand these advanced scales one needs to know how the body mass index works and how that affects the measurements of each individual differently.
The first aspect one should know is the intentions of Quetelet’s discovery. The 19th century scientist developed the formula while inventing “social physics”; the use of physics to explain certain human traits. In 1972, Ancel Keys published an article in a scientific journal stating that BMI was the best way to determine body fat percentages in a population of people. The scientist mentioned clearly that the body mass indexes ability to accurately measure an individual’s fat percentage had not been proven. Still, many doctors and scientist today base most patient evaluations on this formula due to its easily obtained and charted numeric representation.
Calculating one’s body mass index is rather simple. Since it is just a correlation between the height and weight of a person, the mathematical context is easy to gauge. By taking one’s weight in pounds and then dividing it by the square root of their height in inches, then multiplying 703 by the result, an individual can determine their place on the chart. Ideal index numbers for most countries are individuals who fall in the 20 to 24.9 range. These individuals have a lower risk of mortality, diabetes, heart disease and high blood pressure. As an individual’s index climbs above 25 they are classified as overweight and their risk of premature death and life-threatening disease increase. Over 30 and one is considered obese and over 35, morbidly obese. Needless to say, individuals classified in these ranges are at a significantly higher risk of death or disease.
The position some scientists have on the inaccuracies of the body mass index is its inability to factor in differing skeletal types. Numerous studies have shown a troubling effect of this missing detail. A tall man with a narrow frame may be considered overweight on the index even though they have a low body fat percentage and are healthy. The best way for one to determine their BMI is to use frame measurements in conjunction with the index. These measurements are wrist and neck circumference, elbow width and the overall height of a given gender. There are numerous calculators available on the internet to aid an individual in this calculation. Once a frame size has been determined, the individual should add around 10% for a larger skeletal structure and subtract 10% for a smaller frame.
To get an accurate measurement, the newer body fat measuring devices use a light, electronic pulse to determine the difference between fat and muscle. This means of measurement is called a BIA or bioelectrical impedance analysis. Basically, the currents travel faster through lean muscle than they do fatty tissue. This resistance is then measured by the scale and determines how dense a person’s body is. Individuals can sometimes confuse this with a body fat percentage but these types of devices only determine body density.
To get the most accurate results from these scales one should keep a few things in mind. First of all, even if the measuring device doesn’t show the correct data for an individual’s body type, one can still monitor changes. To do this they must be consistent every time they weigh themselves. The position of one’s feet, types of food consumed and how much water is in their system can all adversely affect results. To get the best out of these types of equipment, one must standardize their testing. Be sure to make each weighing session as closely related as possible.
When buying or shopping for the right scale, be sure to take a few things into account. Understand who is going to be using the machine. If children will be primarily measured, ensure that the device can be calibrated for their smaller sizes. Also, athletes that maintain strenuous workout routines should also buy a machine that can be set to their size. This choice can be vital and return more accurate results. If many different people will be using the same device, one should invest a little more money and purchase one that can store user data. Many of these allow “guests” to check their BMI without using the memory functions. This feature alone can help keep one motivated by charting changes over time. In this case, the more expensive the device is, the more accurate it tends to be.
There are several techniques to remember when using these devices. By following these guidelines, one can achieve a more accurate chart of their progress. Always drink a set amount of water 45 minutes before testing. Try to take measurements at the same time every day. A hard one to do, but essential, is to ensure that one’s body temperature is the same at every testing. To do this, do not take measurements after exercising. Sweating will affect the results and body temperature will fluctuate. After each use, clean, with alcohol, the foot pads to ensure a consistent electrical pulse reading. By following a set routine – as one does with an exercise program – when performing daily tests, one will be able to accurately chart any improvement.
A BMI scale, when used properly, can help motivate an individual by charting progress over time. However, one should shop and research the best device available before purchasing. These machines can be accurate and helpful when used properly and with a well-designed diet and exercise program.