New research conducted by the University of North Carolina School of Medicine has shown that exercising can be beneficial for bone health and may result to the burning of fat found within the bone marrow leading to improved bone quality in a just a few weeks . This study has since been published in the Journal of Bone and Mineral Research and shows evidence that obese individuals who are known to have poorer bone quality may actually obtain greater health benefits to their bones from exercise .
A well-known physician and assistant professor of endocrinology and metabolism at the University of North Carolina at Chapel Hill, Maya Styner mentioned that one of the biggest clinical benefits obtained from this research is that exercise is not just good for individual health but even better when it comes to bone health. Data obtained from monitoring test mice showed a significant increase in bone just by running alone. Styner acknowledged that while research in mice is not directly translatable to humans, it should be noted that the type of stem cells that produce bone and fat in mice are very similar if not the same to the types which produce bone and fat in humans. She also mentioned that while this kind of research would be beneficial to combating common health problems like obesity and bone health, it could also aid in providing additional information into the factors causing bone degradation in common health-related conditions like diabetes, arthritis, anorexia, osteoporosis and fractures. Their studies on bone biomechanics have also shown that the quality and strength of the bone significantly increases with exercise, more so in obese individuals .
Bone and marrow
Marrow plays an essential part in bone development as aids in organizing the formation of bone and cartilage while concurrently forming blood cells, immune cells and cancerous cells. It is also involved in the production of fat which is popular in cooking however the physiological role of bone marrow fat is still unknown. It was commonly thought that bone marrow fat serves as a special fat reserve that was not as readily used as an energy source as other fat stores . While previous research has shown that a greater portion of marrow fat may increase the risk of fractures, Styner and her research may now prove otherwise.
Reduction in obese mice fat cells
Styner’s research group performed their experiments on two groups of mice. While one group was fed a normal diet, the other group received a high-fat diet. At just four months of age, half the mice in each group were given a running wheel. Data obtained showed that while the obese mice started with more and larger fat cells in their bone marrow, after exercising for just six weeks both groups showed a significant reduction in the overall size and amount of fat cells . Over time the results further showed that while there was no change in the amount and size of fat cells in lean mice, this had been reduced by more than half in obese mice. In addition, the thickness of their bones had also improved significantly further indicating that marrow fat can be burned off through exercise and that exercise is in fact good for bones [1,3].
While this is great news, there is however some important questions that needs to be answered. One of which is what is the exact relationship between burning marrow fat and obtaining better bones. Styner and her research group admit that while there is a lot of evidence to suggest that marrow fat is being used as fuel to make more bone, more work needs to be done to actually prove this. However, this isn’t an easy task as marrow fat it being encased in bone. While the groups previous work utilised micro CT imaging, the new study, utilised a new and sophisticated MRI machine to assess the marrow fat. This not only eliminates the need for a toxic tracer but allows for highly detailed imaging of living organisms allowing scientists to study bone marrow in a much more reliable fashion.
Styner and her research group are now working with a range of collaborators to develop and adapt new methods for studying bone marrow dynamics in a range of other health related conditions like post-menopausal osteoporosis .
 Derewicz , M. 2017. Another reason to exercise: Burning bone fat — a key to better bone health. Available at: https://www.eurekalert.org/pub_releases/2017-05/uonc-art051817.php
 University of North Carolina Health Care. “Another reason to exercise: Burning bone fat a key to better bone health.” Science Daily, 18 May 2017. Available at: www.sciencedaily.com/releases/2017/05/170518140220.htm
 Maya Styner, Gabriel M Pagnotti, Cody McGrath, Xin Wu, Buer Sen, Gunes Uzer, Zhihui Xie, Xiaopeng Zong, Martin A Styner, Clinton T Rubin, Janet Rubin. Exercise Decreases Marrow Adipose Tissue Through ß-Oxidation in Obese Running Mice. Journal of Bone and Mineral Research, 2017; DOI: 10.1002/jbmr.3159