Influence of age on thirst and fluid intake

Area of Science:

• Gerontology
• Physiology
• Nutrition Science

Background:

• Older adults maintain adequate daily fluid intake but exhibit impaired responses to dehydration.
• Aging impacts physiological systems controlling thirst and satiety, affecting fluid balance.
• Limited data exist on thirst regulation in children compared to adults.

Purpose of the Study:

• To investigate the effects of aging on thirst sensation and fluid intake regulation.
• To compare fluid balance restoration in older adults versus younger individuals.
• To explore potential differences in thirst control mechanisms between children and adults.

Main Methods:

• Review of recent evidence on osmolality, thirst sensation, and baroreceptor function in older adults.
• Analysis of fluid intake and balance restoration under various physiological challenges.
• Comparison of data between elderly individuals, young adults, and children.

Main Results:

• Older adults have a higher baseline osmolality and osmotic operating point for thirst.
• Diminished thirst and satiety responses to baroreceptor unloading/loading occur in the elderly.
• Fluid balance restoration is slower in older adults following dehydration or hyperosmotic stimuli.

Conclusions:

• Aging alters thirst and satiety mechanisms, leading to reduced fluid intake and slower restoration during physiological stress.
• Understanding these age-related changes is crucial for maintaining hydration in older populations.
• Further research is needed on thirst regulation in children, particularly non-homeostatic factors.