Dynamic Disc Designs
Stature Change

Effect of Time of Day on the Magnitude of Stature Change Response

Goal of the Study?

In this case-control study from researchers in Thailand and Australia, published in the journal; Trends in Sciences 1 the authors’ goal was to investigate the effect of time of day (morning versus afternoon) on the variability of the change in stature of participants with Chronic Lower Back Pain (CLBP) on two consecutive days.


Why are they doing this study?

Prolonged sitting places load on the lumbar discs.  The resulting stress from both body mass and gravity reduces disc height, causing what is termed “Stature Loss”.  This loss in stature normally varies over the course of a day but there is some confusion over the magnitude of this diurnal compression and its recovery.  Previous research has shown that the rate of change in stature occurs in two phases; fast and slow.  Stature loss has been reported to be significantly greater when an individual rises in the morning and gradually slows during the day.  This research study is an attempt to understand the variability in the stature change response and determine if this change is a result of time of day effects or measurement variations.



What was done?

Forty-four participants (50:50 male: female) with Chronic Lower Back Pain (CLBP) were recruited for a same-participant test-retest design study.  The authors defined CLBP as pain between the T12 and L5, which was not referred to beyond the knees and had been present for at least three months. Using seated stadiometer variations in stature change were recorded at a similar time for two consecutive days.  One half of the group was assigned to the morning and the other half the afternoon.  The next week the groups were reversed.  Stadiometer readings were taken every 15 seconds over a series of two-minute intervals.  An average of 75 data points were averaged to reduce uncontrollable movement and breathing patterns that may influence the recorded stature loss.


What did they find?

There were slight differences in the amount of stature loss between the morning and afternoon sessions.  0.995mm in the morning and 1.149mm in the afternoon.  But due to the large variations in stadiometer readings, these results were not statistically significantly different.


Why do these findings matter?

When applying a medical treatment one must determine if the medical intervention caused stature changes or if the changes were due to natural variation. Even though this study did not prove statistically that there is a difference between morning and afternoon, it did show that there appear to be smaller changes in the morning when compared to the afternoon.


At Dynamic Disc Designs, we understand that spinal symptoms can correlate to the natural diurnal rhythms of disc height. We have thought carefully about this and provide dynamic disc models to help professionals make sense of a patient’s symptoms.


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