Diurnal variation on height in 347 male academic students

【Objective】 To explore the regularity of diurnal variation of height.【Method】A total of 347 male were recruited(21 to 24 years old) in this study,height and sitting height were measured at 6:30,12:30 and 21:30 of the same day,and ANOVA was used to analyze the difference of three groups.【Results】The average value of height was(172.95±5.23) cm in the morning,(171.95±5.21) cm at noon and(171.51±6.82) cm in the evening.There were significant differences among groups(P0.05).The average value of sitting height was (93.71±2.91) cm in the morning,(92.77±2.92) cm at noon and(92.44±2.96)cm in the evening.There were significant differences among them.Compared with the morning,the value of height and sitting height at noon and in the evening decreased significantly(P0.05,P0.01).【Conclusion】According to the morning,noon and evening,the diurnal variation of height and sitting height show the tendency of descending.The average value of height descends 1.43 cm,the descending almost occurs in the morning,which was 0.94 cm,accounted for 74% of whole height descending in a day,and the sitting height descending accounts for 89% of the descending.Diurnal changes of height show that precise and standard height survey should be carried out at noon.