Vision
Normative structural changes mean we see less well in the dark, are more susceptible to glare and take longer to adapt to changes in illumination. Changes in the ability of the lens to focus and adjust also occur. Specific disease processes that impact on vision and increase with age include cataracts, glaucoma and macular degeneration.
Taste
Sensitivity to the four basic tastes (sweet, salty, sour, bitter) decreases, with the largest change in saltiness and the smallest in sweetness.
Skin and Hair
Wrinkling and sagging of the skin occurs with changes in the middle (dermal) layer of the skin. A decrease in collagen leads fibres to become more brittle, compromising the ability of the skin to conform to the movement of muscles and bone. Sun damage accelerates this process. Hair loses pigmentation due to a decrease in melanin production in hair follicles; hair gradually thins in both men and women.
Regulatory system
Changes to kidneys and connective tissue in the bladder may be associated with incontinence. Around 19% of women and 8% of men over 60 experience some incontinence. Stress incontinence is more common in women (e.g. when sneezing); urge incontinence (lack control or voiding with little warning, which may be related to prostatic disease) is more common in men.
Hearing
Gradual hearing loss begins around 25 years of age, and at first it is limited to high-pitched sounds (presbycusis) – it has minimal impact in young adulthood as it doesn’t affect frequencies in normal speech. Hearing loss that is not remediated by use of hearing aids has been linked to falls due to loss of balance, and to increased risk of cognitive decline.
Central nervous system
These changes will be considered in the section on cognitive changes.
Cardiovascular system
Changes that commence in midlife accelerate in old age. The cells in the heart are slower to contract and less responsive to the messages that control contractions. The heart has diminished capacity to pump blood and the blood carries less oxygen. Aerobic exercise can minimise these changes. Cardiovascular disease is the leading cause of death in Australia.
Body weight
This typically increases from the 20s until the mid 50s, after which it declines. Mid-late life weight loss is usually due to the loss of lean body mass (muscle and bone) rather than loss of fat.
Body build and joints
There is a reduction in standing height, particularly for women. The loss of bone mineral content in the vertebrae leads them collapse and cause compression in the length of the spine. Changes in joints and flattening of the arches of the feet also occur. Osteoporosis can develop as demineralisation leads bones to become more porous and brittle, putting people at risk for falls and fractures. Osteoarthritis is a degenerative joint disease more common in older adults that can impact on physical functioning.
Autonomic nervous system
The capacity to regulate body temperature decreases, and slower vasoconstrictor response reduces the ability to raise the core temperature when the peripheral temperature drops. Older adults don’t sweat as much and have lower thirst sensitivity. Sleep problems are prevalent: 23% of people over 60 report having sleep problems “often” or “all of the time” (compared to 13% of general population).