Patterns of urine flow and electrolyte excretion in healthy elderly people.

Abstract

Twenty four young (mean age 29-2 years, range [25][26][27][28][29][30][31][32][33][34][35] and 21 elderly (mean age 66-5, range 60-80) healthy subjects collected their urine in timed aliquots over 24 hours. The elderly subjects had been selected for their fitness by clinical and laboratory examinations and all lived independently at home. Sodium and potassium excretions were reduced in the elderly subjects compared with the young subjects, potassium excretion considerably so. This was despite similar 24 hour urine volumes and total solute excretion by both groups.The ratios of rates of excretion of water, electrolytes, and solutes during the night to the rates of excretion during the day were found to be higher in the elderly than the young subjects.Reduced day to night ratios of urinary excretion may be partly responsible for complaints of nocturia and sleep disturbance in elderly people. Introduction For many years it has been known that urine flow is lower at night than during the day in healthy subjects.' There is also an accompanying nocturnal reduction in electrolyte excretion.2 It has been speculated that reduction in urine flow at night in mammals may have evolved to permit undisturbed sleep.3Several studies of excretory rhythms in old patients have been reported.4-9 The first study was of patients in psychiatric hospitals4 5; the second of elderly patients in hospitals long term6; the third of nine patients in hospital, only two of whom were

Nocturnal Sodium Excretion, Blood Pressure Dipping, and Sodium Sensitivity

“…12 Wide variation of subject age, however, might have confounded this analysis, because older subjects tend to have higher ratios than younger subjects. 9,11,13 Bultasova et al 14 supported the findings of Dyer et al 12 in a small study comparing circadian rhythms of sodium excretion in 8 young borderline hypertensive men and 6 healthy age-matched normotensive subjects. All of the subjects maintained normal daily activities, but nighttime studies were performed in hospital after adaptation to a regimen of sleep between 10:00 PM and 6:00 AM and to a 135-mmol sodium per day diet.…”

The standardisation of terminology in nocturia: Report from the standardisation sub‐committee of the International Continence Society

“…This value varies considerably from person to person and normally increases with age. Healthy young adults from 21 to 35 years of age excrete around 14 AE 4% or their total urine between the hours of 11 p.m. and 7 a.m. (95% CI = 10-19%) , whereas older people excrete an average of 34 AE 15% (95% CI = 30-36%) Kirkland et al, 1983]. Thus, nocturnal polyuria may be de¢ned as an output greater than of 20% of the daily total in the young and 33% [Carter, 1992] in the elderly with the value for middle age probably falling somewhere between these two extremes.…”

Antidiuretic hormone in elderly male patients with severe nocturia: a circadian study

“…However, in animals physiological changes caused by ageing decrease the kidney's ability to condense urine and induce polyuria [12]. As in humans, the ratio of night to daytime urine increases with age [13,14]. This is a result of either a lack of nocturnal serum ADH surge with age or an increase in atrial natriuretic peptide [15].…”

“…Mean ( SD , range) total PSA and free PSA levels were 2.18 (1.76, 0.08-5.15) and 0.07 (0.54, 0.026-1.30) ng/mL, respectively. The IPSS was 15.67 (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)). …”