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Impact of Running Exercise on the Intervertebral Disc

Studies evaluating how running may affect other connective tissues, such as intervertebral discs (IVD), have been scarce in general.

In a brand-new study, Shu and colleagues ( https://pubmed.ncbi.nlm.nih.gov/38204324/ ) systematically reviewed studies that evaluated IVD morphology or composition changes in response to running exercise, to determine the impact of running exercise on IVD.

A total of 13 studies with 632 participants were included in the final analysis.

Six studies evaluated the acute effects of running on IVD:

4 studies found that the stature, vertebral column height or disc height (volume) decreased acutely after running compared with pre-run (https://pubmed.ncbi.nlm.nih.gov/8081404/ , https://pubmed.ncbi.nlm.nih.gov/18796772/ , https://pubmed.ncbi.nlm.nih.gov/3779339/ , https://pubmed.ncbi.nlm.nih.gov/18796880/ , https://pubmed.ncbi.nlm.nih.gov/21672362/ , https://pubmed.ncbi.nlm.nih.gov/

2648342/ ).

Cross-sectional evaluation was conducted in 5 studies to compare IVD status between chronic runners and controls, and MRI was used to examine IVD parameters in all 5 studies.

In general, most studies found that runners possess better IVD health-related parameters (i.e., greater IVD height and higher T2 values(representing higher water content and proteoglycan content), lower Pfirrmann scores (meaning lower disc degeneration) compared with their non-running counterparts (https://pubmed.ncbi.nlm.nih.gov/32084224/ , https://pubmed.ncbi.nlm.nih.gov/28422125/ , https://pubmed.ncbi.nlm.nih.gov/32545639/

Two longitudinal study found no significant difference in IVD before and after training for marathon in runners (https://pubmed.ncbi.nlm.nih.gov/34541607/ ), resp. no significant difference in changes of IVD between high level runners and controls after 15 years of follow-up (https://pubmed.ncbi.nl

.nih.gov/19305975/ ).

It can be inferred that the load sustained during running seems to extrude water out of the nucleus. This extrusion occurs through the vascular pores located in the cartilaginous endplate and moves into the vertebral body (https://pubmed.ncbi.nlm.nih.gov/6518283/ , https://pubmed.ncbi.nlm.nih.gov/3441837/ , https://pubmed .

cbi.nlm.nih.gov/18796880/ )

While the outer ring of the IVD receives nutrients from the surrounding vascular system, the inner ring and nucleus pulposus acquire nutrients by moving large amounts of fluid through the IVD tissue and diffusing through the vertebral endplate (https://pubmed.ncbi.nlm.nih.gov/16595440/ ).

The pressure on the IVD needs to be within an appropriate range to promote IVD health. Nucleus pulposus cells showed an anabolic response to light-to-medium intensity static compression, osmotic pressure, or hydrostatic pressure, while higher intensity static compression promoted a catabolic response (https://pubmed.ncbi.nlm.nih.gov/30569032/ ).

Mechanical disc loading like moderate running with an appropriate load, frequency, and duration could promote stem cells to differentiate into “discogenic” cells (https://pubmed.ncbi.nlm.nih.gov/21541667/ ). This indicates that IVD has a possible anabolic “loading window,” ie, a certain appropriate pressure might be beneficial for IVD (https://pubmed.ncbi.nlm.nih.gov/28962911/ , https://pubmed.ncbi.nlm.nih.gov/28767637/ , https://pubmed.ncbi.nlm.nih.gov/26684430/ ).

The results seen in the acute effect studies included in this review might be due to the time window at which measurements were taken. It is possible that, after a period of recovery, these acute height and volume reductions might recover and reach a supercompensation state, which may lead to the better IVD parameters observed in habitual runners compared with the control group of cross-sectional studies.