Human body weight is a person's mass or weight. Strictly speaking, body weight is the measurement of

mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...

without items located on the person. Practically though, body weight may be measured with clothes on, but without shoes or heavy accessories such as mobile phones and wallets, and using manual or digital

weighing scale A scale or balance is a device used to measure weight or mass. These are also known as mass scales, weight scales, mass balances, massometers, and weight balances. The traditional scale consists of two plates or bowls suspended at equal d ...

s. Excess or reduced body weight is regarded as an indicator of determining a person's health, with body volume measurement providing an extra dimension by calculating the distribution of body weight. Average adult human weight varies by continent, from about in Asia and Africa to about in North America, with men on average weighing more than women.

Estimation in children

There are a number of methods to estimate weight in children for circumstances (such as emergencies) when actual weight cannot be measured. Most involve a

parent A parent is either the progenitor of a child or, in humans, it can refer to a caregiver or legal guardian, generally called an adoptive parent or step-parent. Parents who are progenitors are First-degree relative, first-degree relatives and have ...

or health care provider guessing the child's weight through weight-estimation formulas. These formulas base their findings on the child's age and tape-based systems of weight estimation. Of the many formulas that have been used for estimating body weight, some include the Advanced Pediatric Life Support formula, the Leffler formula, and Theron formula. There are also several types of tape-based systems for estimating children's weight, with the best-known being the Broselow tape. The Broselow tape is based on length with weight read from the appropriate color area. Newer systems, such as the PAWPER tape, make use of a simple two-step process to estimate weight: the length-based weight estimation is modified according to the child's body

habit A habit (or wont, as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously. A 1903 paper in the '' American Journal of Psychology'' defined a "habit, from the standpoint of psychology, ...

us to increase the accuracy of the final weight prediction. The Leffler formula is used for children 0–10 years of age. In those less than a year old, it is :

m = \tfraca_m + 4

and for those 1–10 years old, it is :

m = 2a_y + 10

where ''m'' is the number of kilograms the child weighs and ''a_m'' and ''a_y'' respectively are the number of months or years old the child is. The Theron formula is :

m = e^

where ''m'' and ''a_y'' are as above.

Fluctuation

Body weight varies in small amounts throughout the day, as the amount of water in the body is not constant. It changes due to activities such as drinking, urinating, or exercise. Professional sports participants may deliberately dehydrate themselves to enter a lower weight class, a practice known as weight cutting.

Ideal body weight

Ideal body weight (IBW) was initially introduced by Ben J. Devine in 1974 to allow estimation of drug clearances in obese patients; researchers have since shown that the

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

of certain drugs relates more to IBW than total body weight. The term was based on the use of insurance data that demonstrated the relative mortality for males and females according to different height-weight combinations. The most common estimation of IBW is by the Devine formula; other models exist and have been noted to give similar results. Other methods used in estimating the ideal body weight are

body mass index Body mass index (BMI) is a value derived from the mass (Mass versus weight, weight) and height of a person. The BMI is defined as the human body weight, body mass divided by the square (algebra), square of the human height, body height, and is ...

and the Hamwi method. The IBW is not the perfect fat measurement, as it does not show the fat or muscle percentage in one's body. For example, athletes' results may show that they are overweight when they are actually very fit and healthy. Machines like the

dual-energy X-ray absorptiometry Dual-energy X-ray absorptiometry (DXA, or DEXA) is a means of measuring bone mineral density (BMD) with Spectral imaging (radiography), spectral imaging. Two X-ray beams, with different energy levels, are aimed at the patient's bones. When soft t ...

can accurately measure the percentage and weight of fat, muscle, and bone in a body.

Devine formula

The Devine formula for calculating ideal body weight in adults is as follows: * Male ideal body weight = + × (height (cm) − 152) * Female ideal body weight = + × (height (cm) − 152)

Hamwi method

The Hamwi method is used to calculate the ideal body weight of the general adult: * Male ideal body weight = + × (height (cm) − 152) * Female ideal body weight = + × (height (cm) − 152)

Usage

Sports

Many disciplines in

weightlifting Weightlifting or weight lifting generally refers to physical exercises and sports in which people lift weights, often in the form of dumbbells, barbells or machines. People engage in weightlifting for a variety of different reasons. These can ...

combat sport A combat sport, or fighting sport, is a contact sport that usually involves one-on-one combat. In many combat sports, a contestant wins by scoring more points than the opponent, submitting the opponent with a hold, disabling the opponent (''knock ...

s separate competitors into

weight class Weight classes are divisions of competition used to match competitors against others of their own size. Weight classes are used in a variety of sports including Rowing (sport), rowing, Weightlifting#Weightlifting sports, weight lifting, and especi ...

es.

Medicine

Ideal body weight, specifically the Devine formula, is used clinically for multiple reasons, most commonly in estimating renal function in drug dosing, and predicting

pharmacokinetics Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to describing how the body affects a specific su ...

in morbidly obese patients.

Average weight around the world

By region

Data from 2005:

By country

Global statistics

Researchers at the

London School of Hygiene and Tropical Medicine The London School of Hygiene & Tropical Medicine (LSHTM) is a public university, public research university in Bloomsbury, central London, and a constituent college, member institution of the University of London that specialises in public hea ...

published a study of average weights of adult humans in the journal ''

BMC Public Health ''BMC Public Health'' is a peer-reviewed open-access scientific journal that covers epidemiology of disease and various aspects of public health. The journal was established in 2001 and is published by BioMed Central. Abstracting and indexing ...

'' and at the United Nations conference

Rio+20 Rio or Río is the Portuguese and Spanish word for "river". The word also exists in Italian, but is largely obsolete and used in a poetical or literary context to mean "stream". Rio, RIO or Río may also refer to: Places United States * Rio, Fl ...

.Data extracted from

References

External links

* {{Use dmy dates, date=April 2017 Auxology Anthropometry Mathematics in medicine