Okay, this can get complicated, but let’s break this concept down a bit further.
Bones go through a normal cycle of maintenance, repair, and remodeling. Cells known as the osteoclasts and osteoblasts supervise this process and I imagine these cells as little construction managers whose job it is to keep bone resorption and bone formation in a steady balance. Sometimes, however, these cells are not able to effectively maintain the balance and bone resorption exceeds bone formation. Typically diagnosed if the z-score is -2.5 or lower (1), this is known as osteoporosis. Of note, the z-score is calculated through a DEXA (Dual Energy X-ray Absorptiometry) scan and compares your results with your age-matched peers. Additionally, even though scores may not indicate osteoporosis, it is important to see any trends in bone density loss or consider any fragility fractures. These are signs that the bones are not healthy and require medical attention.
We typically associate osteoporosis with our frail elderly population, but what we have found is that decreased bone density tends to develop early in individuals with eating disorders or disordered eating. In fact, approximately 50% of adults with eating disorders have developed osteoporosis after a brief duration of the illness (2-5). There are medications that can treat decreased bone density, but, unfortunately, it does not resolve as quickly as it develops.
So how does exercise come into the equation when it comes to decreased bone density? It is well-documented throughout the literature on the frail elderly that weight-bearing exercise is an appropriate treatment intervention. On the average, our frail elderly may be more sedentary and there is a need to introduce simple weight-bearing movements to facilitate increases in bone density. On the contrary, individuals with eating disorders or disordered eating may perhaps move too much or, another way of thinking about it, load their bones with excessive weight-bearing movement. One of the key differences between the two groups is that for individuals with eating disorders, the atrophy is due to malnutrition and not the anticipated process associated with aging. Muscle tissues are not fueled and are unable to generate adequate force or apply appropriate amounts of stress to the bones in order to stimulate this balanced cycle. So, as you can imagine, the result is increased risk for injury to bones, muscles, and other tissues.
We have to approach movement and exercise from a different framework. Weight-bearing and strength-based movements are still appropriate, but it is imperative to integrate them at a graduated pace. One that follows closely with nutritional rehabilitation. As a Physical Therapist skilled in the treatment of individuals with eating disorders and disordered eating, discussion of bone density loss and appropriate treatment from a movement framework is such a powerful component of my work. I love being creative in way to integrate meaningful movement while still honoring the healing process of the body.
Want to know more? Ask me questions about it, let’s connect…
1. https:www.nof.org accessed November 2017.
2. Grinspoon S, Thomas E, Pitts S, et al. Prevalance and predictive factors for regional osteopenia in women with anorexia nervosa. Ann Intern Med. 2000;133(10):790-794.
3. Mehle PS, MacKenzie TD. Treatment of osteopenia and osteoporosis in anorexia nervosa; a systematic review of the literature. Int J Eat Disord. 2009;42(3):195-201.
4. Mehler PS, Krantz M. Anorexia nervosa medical issues. J Womens Health. 2003;12(4):331-340.
5. Vestergaard P, Emborg C, Stoving RK, Hagen C, Mosekilde L, Brixen K. Fractures in patients with anorexia nervosa, bulimia nervosa, and other eating disorders – a nationwide register study. Int J Eat Disord. 2002;32(3):301-308.