Further observations on diurnal variation in standing height.

A total of 328 daily assessments of standing height were made on one boy between the ages of 12.83 and 13.95 years; 292 of these were replicates to establish reliability of measurement. On 300 days, measurements were taken in the morning within 1/2 h of rising (which varied between 0700 and 1100 h) and repeated before bed on the same day, between 2100 and 2300 h. The standard error of measurement from 292 duplicate measurements was 0.12 cm. A mean of 0.98 +/- 0.2 cm decrease in stature occurred during the course of the day. A similar decrease was found on three occasions after 2-3 h naps.