The Positive Effect of Running on Discs

I recently read the book Born to Run by Christopher McDougall.  It is a great read, even if you do not like running.

To stay on the theme of running, a recent article in Spine investigated the effect of running exercise on intervertebral discs.  The study is interesting and likely has some application to thinking about backs and exercise generally.Degenerative disc or Herniated disc

Disc issues are central to thinking about most back pain.  We all have heard of or dealt with herniated discs, “degenerative disc disease”, slipped discs or related issues. 

The intervertebral disc is made up of two principal components:

• Nucleus pulposus
• Annulus fibrosus

I often use the example of a jelly donught to roughly characterize the anatomy of a disc.  The nucleus pulposus is like the jelly center of a donught.  It is the water-rich, gelatinous center of the disc.  The nucleus pulposus is generally maintained under high pressure (especially with sitting and positions of forward flexion at the waist).  Two main functions of the nucleus pulposus include: (1) carrying the downward weight (i.e., axial load) of the human body and (2) acting as a ligament and bind the vertebrae together.

The annulus fibrosus is roughly related to the outer part of the doughnut that contains the inner jelly component.  It is fibrous and has lower water content when compared to the nucleus. The main job of the annulus fibrosus is to contain the highly pressurized nucleus.  The annulus is made of 15 to 25 concentric sheets of collagen (a tough cartilage-like substance). 

Stepping back to look at this issue with a broader lens, degeneration of discs is what everyone treating and living with back pain is interested in.  Fix disc degeneration and you have the holy grail of spine medicine. 

On one hand studies have shown that microtrauma in this annulus fibrosus is part of the process that leads to degenerative disc changes over time.  Other studies have shown that a decrease in the extracellular matix of intervertebral disc cells is associated with disc degeneration.[1]

[My brother-in-law recently commented that my posts were far too technical and not targeted for a “lay audience.  I am sure I am drifting into this territory right now but it seems important to make this point.]

Why do we care about the extracellular matrix of discs?  Well, some people believe that running is hard on the joints and can be equally hard on backs.[2]

In the spirit of Born to Run [which suggests that “the secret to happiness is right at your feet, and that you, indeed all of us, were born to run].  I would like to argue that running can be good for backs.  The above referenced study by Brisby et al. investigated the effects of running on discs using animal model.  The study demonstrated that a running regimen created the following in healthy discs: [3]

• Increase in cellular numbers with the annulus fibrosus after exercise
  • The exercise group showed a 25% increase in cell numbers
• Increase in extracellular matrix production in the annulus fibrosus and nucleus pulposus
• No evidence of an increase in cellular apoptosis (or cell death)

The authors concluded that “moderate exercise may have beneficial effects on intervertebral disc cells.”[4]  

So go ahead and run.  You were born for it (or at least rats were).

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[1] Spine 2010; 35(15):1429-1436

[2] J Am Acad Orthop Surg 2006; 14: 726-735

[3] Spine 2010; 35(15):1429-1436

[4] Spine 2010; 35(15):1429-1436

Comments

[Rachel]

I'm wondering how relevant rat studies are, since rats run on all fours while we ar upright and bipedal. The vertical load would be greater.

[The Back Exercise Doctor]

I can appreciate your question about whether a rat model is applicable. There are always limitations to animal models for studying human issues. This study is helpful in a broader context of research on this topic. In the spirit of "Born to Run" I would like to think that running is good for the back, just as it is good for the heart and other tissues. A study in the Spine Journal looked at the effects of intensive special forces training on lumbar spines. They found that "the soldiers in this study completed the 14-week training, which involved loading of their spines far beyond the levels recommended by the US National Institute for Occupational Safety and Health without sustaining irreversible damage to their spines or knees." (Spine J. 2008 Jul-Aug;8(4):578-83. Epub 2007 Mar 2.)

Thanks for your comments and feedback.