01/08/2026
A fresh look at what leads to optimal disc health - regular activity for the win!
Just published 🔥
𝗥𝗲𝘁𝗵𝗶𝗻𝗸𝗶𝗻𝗴 𝘁𝗵𝗲 𝗱𝗶𝘀𝗰: 𝗳𝗿𝗼𝗺 𝗱𝗲𝗴𝗲𝗻𝗲𝗿𝗮𝘁𝗶𝘃𝗲 𝗻𝗮𝗿𝗿𝗮𝘁𝗶𝘃𝗲 𝘁𝗼 𝗮𝗱𝗮𝗽𝘁𝗶𝘃𝗲 𝗽𝗼𝘁𝗲𝗻𝘁𝗶𝗮𝗹
📘 Intervertebral disc (IVD) degeneration is still widely presented as an inevitable consequence of ageing and spinal loading (https://pubmed.ncbi.nlm.nih.gov/16915105/). However, mechanobiological data increasingly suggest that this interpretation ignores how strongly disc health depends on dose, type, and variability of mechanical exposure. A brand-new editorial by Shala in BJSM (https://bjsm.bmj.com/content/early/2026/01/05/bjsports-2025-110872) complements the contemporary biopsychosocial framework by highlighting the disc’s capacity for adaptation as one biological dimension within a broader system of physical, psychological and social influences.
💧The IVD is avascular. Disc cells rely almost entirely on diffusion for nutrient supply and waste removal. This diffusion is mechanically driven. Cyclic compression and decompression generate fluid flow, regulate osmotic pressure, and maintain proteoglycan synthesis (https://pubmed.ncbi.nlm.nih.gov/16915105/, https://pubmed.ncbi.nlm.nih.gov/26666742/). When loading is reduced, diffusion decreases, anaerobic metabolism increases, intradiscal pH drops, and catabolic processes dominate (https://pubmed.ncbi.nlm.nih.gov/26409630/).
🏃♂️➡️ Quantitatively, favourable disc responses appear to occur within a relatively narrow loading range. In vivo pressure measurements indicate that moderate dynamic loading generate intradiscal pressures of approximately 0.3–1.2 MPa, a range associated with anabolic or maintenance-oriented disc responses (https://pubmed.ncbi.nlm.nih.gov/28422125/, https://pubmed.ncbi.nlm.nih.gov/26666742/). Loads below this threshold may be biologically insufficient, while sustained or excessive pressures may become harmful. Accelerometry-based MRI studies further refine this concept. Disc adaptations appear most pronounced when acceleration forces fall between 0.44 and 0.59 g, corresponding to brisk walking or slow running. Outside this window—particularly during high-impact or ballistic activities—changes in diffusion and hydration are less favourable, especially in individuals with pre-existing degeneration (https://pubmed.ncbi.nlm.nih.gov/28422125/).
🩻 MRI data support these mechanobiological observations. Cross-sectional studies show that runners exhibit longer T2 relaxation times in lumbar discs compared with sedentary individuals, reflecting higher water and proteoglycan content rather than disc hypertrophy (https://pubmed.ncbi.nlm.nih.gov/28422125/, https://pubmed.ncbi.nlm.nih.gov/32084224/). These adaptations are most evident in the nucleus pulposus, consistent with its role in load distribution and osmotic regulation. But we would like to add that interventional exercise studies so far were not successful in improving disc parameters in low back pain patients (https://pubmed.ncbi.nlm.nih.gov/32211998/)
📊Importantly, disc tolerance is not constant throughout the day. Intradiscal pressure is highest in the early morning due to overnight rehydration and gradually normalises after 60–90 minutes of upright activity. High-load spinal tasks performed immediately after waking may therefore exceed tissue tolerance, even if the same tasks are well tolerated later in the day (https://pubmed.ncbi.nlm.nih.gov/10222525/, https://pubmed.ncbi.nlm.nih.gov/9854759/).
🪑Sedentary behaviour represents a biologically meaningful exposure rather than a neutral state. Longitudinal MRI data show that individuals performing
