With aging the body continues to have a change in weight height bone composition fat composition muscle composition range of motion of the bones due to time and disuse and skin Changes in Body Shape Anthropometry Branch of science dealing with the measurement of the human body Note Measurements are taken in centimeters and kilograms Height For each age there is a bell curve for height distribution Males height increases until the age of 20 and declines by 4 until age 70 Females height increases until 16 18 and declines by 3 by 70 Sorkin et al 1999 Studied 17 different Caucasian populations For both men and women the height did not change much until the age of 40 where the height decreased by 1cm until 60 After 60 women decreased more in height per year This loss in height for both genders are due to Changes in height and shape of vertebrae Loss of muscle tone Postural slump Accelerated loss in stature in women could be due to hormones diet weight physical activity and osteoporosis which women develop more Weight Healthy weight is a better term to use than ideal weight Healthy weight Weight associated with lowest mortality and morbidity rates Since the 1960s obesity in women has increased more than men In the 20 29 y o female group there was a 139 increase in obesity Average weight of women in the US increases until 50 where it then stabilizes until 70 Fat mass increases while muscle mass decreases Average weight of men in the US increases until 40 hits a plateau until 55 and then declines This pattern could be due to Selective survival Young and middle aged people die prematurely so the rest who remain alive are those at a lower weight Cohort effect Older people come from cohorts where obesity is less common Losing weight could simply be part of the aging process for men Men lose both muscle and fat mass The old old cohort has a very low percentage of obese people This could be because of the selective survival effect or due to the higher frequency of disease Involuntary weight loss in the elderly is a bad sign In some cases 24 of those who do lose weight this weight loss comes in hand with diseases such as cancer depression intestinal ulcers thyroid problems and neurological problems Body Mass Index BMI Body weight Kilograms Height Meters squared Higher numbers are associated with higher percentage of fat Yet high bmi could be because of greater muscle mass in trained individuals High bmi are associated with diseases such as diabetes cardiovascular disease hypertension etc While bad to explain distribution of fat it is more accurate than looking at weight alone Classi cations with BMI Overweight 25 29 9 Obese mild 30 34 moderate 35 39 severe greater than 40 Remember that BMI is super accurate because it can overestimate or underestimate a persons fat distribution Other researchers say that waist circumference is a better indicator The more fat in the belly apple shaped the worse Changes in Body Composition Looking at BMI alone isn t god enough since to people of the same weight can have very different body compositions One mostly fat other mostly muscle Fat weighs less but takes up more space muscle weighs more but is more compact The body is separated into two components Fat free mass Made up of water protein and bone minerals Fat mass Using these to estimate the composition of a person not the most accurate since either FM or FFM is indirectly measured and the other is found by subtraction A more accurate way of determining fat composition in a person is by isolating internal abdominal fat from subcutaneous appendicular or truncal fat This is done with expensive lab equipment Body comp is used as a modi able factor in the search for optimal health Manipulated by genetics as well as environmental factors Primary in uences are diet disease and physical activity Body Fat While too much fat is bad we do need a certain amount in the body Needed for energy vitamin storage cell membrane integrity insulation and padding There is essential fat found in the organs and CNS while storage fat is found in adipose tissue Women usually have more fat since more is needed for reproduction Fat Measurements Skinfold measurement Used in clinics Measured with clampers and relatively accurate Measures the fold of the skin at places such as the upper hip abs and back of upper arm It is slightly less accurate for adults over 65 Alternatives Underwater weighing x ray absorptiometry DEXA air plethysmography magnetic resolution Densitometry is the gold standard for estimating body composition BOD POD System Fairly new and uses air displacement instead of water displacement It is quick easy to use and can adhere to special needs of people Bioelectrical Impedance analysis BIA Fairly new Passes a harmless current through a person and sees how much resistance there is There is room for error since each machine is different and the hydration state ca change the results Less invasive DEXA Laboratory use Allows for the measurement of Fat bone and lean tissue Quick and the most precise method of determining composition It is just very expensive Computed tomography CT Expensive and uses a lot of radiation Magnetic resonance imaging MRI Uses magnetic elds and radio waves to produce cross sectional colorful images of the body Important for determining differences between tissues of the body Like CT it can be used on any age group Along with CT it is important to determine visceral fat which is now thought to be more correlated to health than the total amount of body fat Body Fat Distribution Research also indicated that where the fat is deposited is important for determining morbidity Even more so than increases body fat alone Higher amount of fat in the abdominal area rather than the hip thigh area are at increased levels of cardiovascular disease diabetes high bp stroke arthritis sleep apnea and mobility impairments Android male Fat patterns Boys gain more fat around the abdomen before and during puberty Apple shaped Waist to hip ratio if greater than 0 95 then there is an increase in risk of death Waist greater than 40 in then higher risk of morbidity Gynoid female Fat Patterns Girls gain fat around their hips and thighs before and during puberty Pear shaped Waist to hip ratio If greater than 0 8 there is an increase in risk of death Waist greater than 35 in then higher risk of morbidity Fat cells in the abdominal area are more active and when there is too much of it fat is released to the blood and goes to