Please use this identifier to cite or link to this item: http://ahro.austin.org.au/austinjspui/handle/1/10631
Title: Reduced osmotic thirst in healthy elderly men.
Authors: Phillips, P A;Bretherton, M;Johnston, Colin I;Gray, L
Affiliation: Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
Issue Date: 1-Jul-1991
Citation: The American Journal of Physiology; 261(1 Pt 2): R166-71
Abstract: In response to water deprivation or heat stress, healthy elderly men experience reduced thirst compared with a young control group. Because water deprivation and heat stress produce hypertonicity as well as reduced extracellular fluid volume, the aim of this study was to determine whether the elderly also experience reduced thirst in response to hypertonicity without extracellular fluid volume depletion. To achieve this, after an overnight fast, healthy community-dwelling nonsmoking old (65-78 yr, n = 7) and young (20-32 yr, n = 7) men received 120-min hypertonic (0.855 M) and isotonic (0.154 M) saline infusions (0.06 ml.min-1.kg-1) in double-blind randomized order at least 2 wk apart. Both groups had increased thirst (P less than 0.001) and water intake (P less than 0.05) after the hypertonic saline infusion compared with the isotonic saline infusion. However, despite similar plasma sodium increases and less plasma volume expansion during the hypertonic saline infusion compared with the young group, the old group was less thirsty (P less than 0.01) and drank less room-temperature tap water (young 11.1 +/- 1.2 ml/kg, old 3.9 +/- 0.6 ml/kg, P less than 0.001). This reduced thirst in the old group seemed to be mainly due to a lower thirst sensitivity (P less than 0.05) to hypertonicity, although there was also a tendency toward an increased thirst threshold. Plasma arginine vasopressin increases were similar for the old and young groups with hypertonic saline, without significant changes during the isotonic saline infusion in either group.
Internal ID Number: 1858944
URI: http://ahro.austin.org.au/austinjspui/handle/1/10631
URL: http://www.ncbi.nlm.nih.gov/pubmed/1858944
Type: Journal Article
Subjects: Adult
Aged
Aging.blood.physiology
Arginine Vasopressin.blood
Humans
Male
Osmolar Concentration
Osmosis
Sodium.blood
Thirst.physiology
Appears in Collections:Journal articles

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