Age and volume dependent normal frequency volume charts for healthy males

We report age and voided volume stratified normal values for voiding diary parameters, including urine production, in a uniform, nonreferred population of 935 healthy male volunteers.

A total of 935 volunteers kept a 3-day voiding diary and also recorded the time of going to bed and getting up. Additionally, prostate volume was measured using transabdominal ultrasound and the maximum free flow rate was measured with a rotating disc flowmeter. From the diaries we calculated median voided volume and the mean number of voids during the day and night. We also calculated mean urine production in ml per hour during the day and night by assuming constant production between voids.

Volunteers voided a median volume of 220 ml 6 times daily and 0.5 times nightly. They produced 83 ml urine per hour during the day and 48 ml per hour during the night. The median maximum flow rate was 16 ml per second and median prostate volume was 31 ml. All diary parameters, free flow rate and prostate volume depended significantly on International Prostate Symptom Score. However, all parameters except urine production during the day depended significantly on age and all except prostate volume depended significantly on voided volume.

Values in a subgroup of 788 volunteers with an International Prostate Symptom Score of 10 or less may be considered normal for male voiding diary parameters. Age and voided volume stratified normal values were also derived.