Height and Posture
People get shorter with age, but not only because of changes in their bones and muscles. Statistics show that people, in general, are becoming taller with each successive generation. The effects of illness, amount of physical activity, nutrition, and care are not completely understood.
The aged person is somewhat stooped in appearance and this makes the extremities look longer. Actually, bone is reabsorbed from the inside surface of the long bones faster than it is formed on the outside surfaces, but this does not affect length. In very old person, the extremities only appear longer because the spinal column is shorter, accounting for loss of height. The fibrocartilage intervertebral discs become drier and thinner. With increasing age, bone decreases in mass and mineral content and the vertebrae compress into shorter, wider structures. A decline in estrogen production in the aging female accelerates the loss of calcium from the bone, causing osteoporosis.
Height is affected by varying degrees of thoracic kyphosis, a curvature of the spine known as “humpback”. The pelvis widens and a slight flexion of hips and knees also decrease stature. Loss of muscle strength and muscle mass add the stooped, forward-leaning posture and flexion of the lower extremities.
To compensate for the spinal curve, the neck is tilted back and held in extension to keep the head up. The extensor muscles of the neck become thicker and the anterior flexor muscles of the neck atrophy and become shorter. The scapulae, or shoulder blades, move forward with the curve and the shoulder span narrows. The lower back becomes flat.
Water, Fat, and Body Weight
Water, Fat, and Body Weight
Ancient researchers believed that aging was related to water loss and the drying out of the body. They were not entirely wrong. With age there is a decrease both in intracellular fluids, and this is one of the reasons dehydration occurs rapidly in the rlderly. The composition of electrolytes, acids, bases, and salts that control cell activities remains the same. Temperature and acidity of body fluids remain constant from youth to old age.
The number of body cells also decreases with age. By age 65, a person has a cell loss of about 30%. This does not mean a one-third reduction in size. Body fat accumulates with age and the large fat cells make up the difference in mass. Overall body weight increases slowly and peaks as adults get into middle age, and then it gradually declines. Women tend to gain weight for a longer period of time and lose less as they age. Fat distribution in women is mostly on the chest, waist, hips, and thighs. In men, fat is deposited at the waist and over the chest and lower addomen.
With very old age there is a decrease in subcutaneous fat in both sexes, predisposing elderly persons to feeling cold. The decrease occurs first in the extremities and then in the trunk. Loss of subcutaneous fat in the extremities makes the skin appear loose and wrinkled over the muscle. The eyes look sunken as the fat layer around the orbit disappears. Hollows in shoulders, chest, and axillae become deep and breasts sag.
Muscle Mass and Strength
Muscle fibers atrophy and decrease in number in the aging person. Fibrous tissue gradually replaces muscle tissue, causing a decline in muscle strength. Loss of muscle strength with aging may also be related to a poor dietary intake of potassium, as well as to loss of neurons and hormones. Aging muscle does not work well because is it not as efficient in using oxygen. Tendons shrink and become sclerotic, limiting the strength and range of movement of the extremities. Slight tremors are normal and are associated with degeneration of the nervous system.
Skin and Accessory Organs
Normal aging of skin is influenced by diet, health, exposure, and heredity. Skin dries and the outer layer turns fragile. The collagen fibers in the dermis, or vascular layer, shrink and become rigid, making the skin less elastic. The loss of subcutaneous fat results in lines, wrinkles, and sagging. Pigment cells-melanocytes-gather and cause age spots.
A decrease in melanin, the color pigment, in hair follicles produces graying of hair. Hair loss occurs more prominently in men. Overall body hair diminishes as one gets older. Scalp, pubic, and axillary hair thins. However, hair in the nose and ears gets thicker, and a woman may note the beginning of a mustache.
Nails of the fingers and toes grow more slowly, turning hard and brittle with long bumpy stripes. The sudoriferous, or sweat, glands diminish in number, size, and activity as they become fibrotic. Older persons are more susceptible to heat stroke. Sebaceous glands secrete less oil to lubricate hair and skin, and dryness is the result.
Reference :
Farrell J : Nursing Care of the Older Person, J.B. Lippincott Company, Philadelphia, 1990.
