Question

a) Discuss the changes in thirst as people age.

b) What is the mechanism behind this change and what have researchers found when studying older versus younger men?

Answer 1

a) Changes in thirst is an age-related problem. Older adults have diminished thirst perception which affects the homeostasis and urinary function. Generally, the older adults feel dry mouth due to the fluid deprivation. Diminished thirst affects the physiologic processes of the body functions during fever, infection which leads to fluid and electrolyte imbalance. Thus diminished thirst sensation interfere with the normal mechanism of the body processes.The factor associated with aging such as the frequent sensation of urination, urge to void, involuntary elimination of urine will make the older to less intake of water. There is an imbalance between the perception of an urge to void and the actual need to empty the bladder.

b) The mechanism behind this change:

Changes in the bladder system and nervous system(the motor function of the spinal cord) will affect the urinary function. Instead of inhibiting the bladder to be empty, the brain stimulates for bladder contraction which urges to void. The cerebral cortex may change the sensation of bladder fullness and incomplete emptying of the bladder due to degenerative changes. In addition, hormonal changes such as decreased estrogen level will increase the sensation of urge to void.

The researchers found that in young adults the sensation starts when the bladder is half-full whereas in the older adults the signals from the sensory receptors of the bladder become delays so the need of urge to void is an emergency. When compared with young adult, the older adults are with diminished thirst due to an absence of volume stimulus. The young adults are with homeostatic control, but the older adults are non-homeostatic control and change in the drinking behavior of elders.