Purpose: Circadian changes in urinary frequency, diuresis and bladder capacity were evaluated in middle-aged and elderly patients.
Materials and methods: A total of 2,703 urinations from 50 men (median age 66 years) was recorded with a 24-hour uroflowmetry system.
Results: During a 24-hour period the elderly group showed increased frequency and decreased bladder capacity. No difference was observed in diuresis between the 2 age groups. From midnight to 6 a.m. frequency in the elderly group was significantly greater (p < 0.01) than that in the middle-aged group.
Conclusions: Increased frequency in the elderly group during these hours was primarily due to an increase in diuresis.