After age 65, most adults experience a 46% to 60% decrease in lean body mass and loss of body water. The matrix of collagen and elastin that transports material between cells becomes cross-linked, resulting in a network of inefficient connective tissue. Collagen becomes insoluble and rigid; elastin becomes brittle and less resilient. The rate at which height is lost increases after age 65, owing to a combination of the loss of body water and bone mass, weakened muscle groups, and deterioration of spinal disks. On average, 1.2 cm (1.5 to 3.0 inches) in height is lost over a lifetime, with women typically losing more height than men.

Elders typically tend to lose weight, in part due to a loss of body water, fat, lean muscle mass, and bone mass. Weight loss may also be attributed to health problems, decline in capacity for self-care, loneliness, and poverty. A decrease in food intake, a decrease in water intake due to concerns about urinary frequency, slowing of peristalsis in the gastrointestinal tract, and lack of exercise may all increase the risk for malnutrition, dehydration, and constipation. Malnourishment increases vulnerability to even minor illness. An assessment of nutritional status is key to promoting good health later in life.

Elders replace epidermal cells every 30 days or more, compared to 20 days or less in younger people. Loss of subcutaneous fat and collagen means that the dermis becomes thinner and loses elasticity. Older skin is more easily damaged, and wound healing is 50% slower than in midlife.