Final answer:
Aged individuals may have less total body water due to physiological changes including tissue atrophy, reduced moisture retention in the skin, decline in muscle mass, and reduced efficiency in the body's regulatory systems that manage water and electrolyte balance. Homeostatic imbalance and lifestyle factors, such as alcohol consumption, can exacerbate the loss of body water with age.
Step-by-step explanation:
Aged individuals of either sex may have less total body water because of a variety of physiological changes associated with aging. As we age, cells, tissues, and organs are affected by senescence, leading to the body's reduced capacity to retain and regulate water. There is atrophy of muscle tissues, a thinning of the skin, and a decrease in cartilage, elements that contribute to reducing the overall water content of the body. The effects of aging on the body's water balance are also compounded by factors such as hormonal changes that reduce the skin's ability to retain moisture and create obstacles in the way the body manages heat and water retention, such as a reduced sweating ability. Dehydration in the elderly can be a challenge as it can exacerbate other age-related health issues.
The reduction in homeostatic efficiency can leave older adults more vulnerable to homeostatic imbalance, dehydration, and diseases. The functional decline of organ systems and the lower activity of accessory structures, like sebaceous glands and sweat glands, contribute to increased risk. Moreover, elderly individuals may not manage their water intake effectively, and other lifestyle factors such as drinking alcohol can further reduce water retention due to its impact on antidiuretic hormone production. These factors together contribute to why aged individuals may experience a decrease in total body water.
Both men and women experience these changes, but certain changes are more pronounced due to gender-specific biological factors. Men typically begin with higher muscle mass and metabolic rates, which could mean different rates of muscle atrophy, while women may have other specific challenges such as reduced bone density. Additionally, the societal roles and healthcare biases towards aging women can impact their overall health, but these are not directly related to the physiological reasons behind reduced body water.