The Relationship Between Bone, Muscle and Type 2 Diabetes

This article was contributed and written by Accredited Exercise Physiologist and PhD candidate at the Institute for Health and Sport (IHES), Victoria University, Rhiannon Healy.

ARE YOUR BONES AND MUSCLES COMMUNICATING?

Have you ever heard the phrase, ‘the key to a healthy relationship is communication’?

This idea is accepted universally as true: if we want any relationship to be healthy, strong and functional, we need to be communicating. But what if I told you this was also true for your bones and muscles?

According to recent research, it’s clear that not only do our bones and muscles talk to each other, but their communication may actually be a key influencer in our overall health and risk of disease, particularly for those affected by type 2 diabetes (T2D).

OUR BONES AND MUSCLES TALK TO EACH OTHER

“The leg bone’s connected to the knee bone. The knee bone’s connected to the thigh bone.” The skeleton dance is a popular song used in schools to educate children about bones. Though not anatomically correct, it highlights how and where our bones are connected.

However, there’s an important element missing from this song: the muscles!

For decades we have known that the skeleton is important for many different aspects of day-to-day function, including locomotion (movement), stature, and protecting our vital organs. But recent research has also found that our bones play a much larger role in overall metabolic health, including our risk of disease, ability to regulate our appetite, insulin function as well as muscle health. It turns out that bone is actually an endocrine organ, meaning it releases proteins that act on other organs, including skeletal muscle.

While it’s always been assumed that the relationship between bone and muscle was purely mechanical, we now know this is not the case and that our bone and muscle both release hormones (osteokines and myokines respectively) that ‘talk’ to each other.

WHY TALKING IS IMPORTANT

Considering many health conditions that affect bone also affect muscle, this hormone communication changed how we thought of the bone-muscle relationship and what it meant for the prevention of different diseases, including osteoporosis (low bone density) and sarcopenia (low muscle mass). It also changed how we thought of the management and treatment of these conditions (such as medications, lifestyle interventions) because interventions used to target bone could now be used to also target muscle, and vice versa.

It also highlighted the importance of considering sex hormones (estrogen and testosterone) and sex-specific differences in bone-muscle talk, as men and women have markedly different muscle and bone-loss trajectories, as well as different levels of risk for different diseases, including T2D.

TYPE 2 DIABETES AND BONE-MUSCLE TALK

T2D is one of the most common metabolic diseases worldwide. It is characterised by the body’s inability to use insulin, impairing glucose uptake from the blood stream and leading to high blood glucose levels and various health complications.

These complications include changes to bone heath, such as an increased risk of bone fractures and fragility, decreased muscle function and mass, reduced testosterone in men and increased testosterone in women.

The opposing responses in testosterone levels between sexes is intriguing, as testosterone plays an important role in bone and muscle health in both men and women. The differences in bone-muscle talk between sexes and what this means for T2D is an exciting new area of research still under investigation (as of 2024).

Bone proteins have been associated with changes to insulin function and glucose metabolism (both positive and negative), and skeletal muscle is one of the largest glucose disposal sites in the body. This bone-muscle talk may be key for treatment and management of insulin resistance (IR) and T2D in both men and women. While we’re still not sure what exactly this looks like, what we do know is that one key intervention can positively benefit all of the above: exercise!

EXERCISE TO IMPROVE YOUR BONE-MUSCLE COMMUNICATION

Exercise is known to simultaneously benefit bone and muscle health. It is also a key lifestyle intervention for managing T2D.

It applies a beneficial stress on the body that prompts us to adapt, making us stronger, faster, fitter and more sensitive to insulin. Regular exercise also preserves important functional aspects our bodies need for healthy ageing with T2D, such as heart health, bone density, muscle mass and strength.

While the notion that exercise is beneficial for T2D is quite familiar to most, research has also found exercise can enhance bone-muscle talk and positively impact sex hormone levels in men and women.

This means that exercise can be prescribed as an intervention to increase the levels of beneficial bone and sex hormones that help with pancreatic function, glucose control, insulin sensitivity and appetite regulation, which are all relevant to the development and management of diabetes.

This expands the list of health benefits professionals can target with exercise, as physical activity is also known to reduce the risk of many preventable diseases, such as cancer and heart disease.

TYPES OF EXERCISE FOR BONE-MUSCLE COMMUNICATION

While resistance training and weight bearing exercises are best known for their benefits for bone density and muscle mass, aerobic exercise also increases the levels of beneficial bone hormones and an individual’s insulin sensitivity.

The focus should not necessarily be on the type of exercise, but rather the consistency of the exercise. Any exercise is better than no exercise, particularly when done regularly. So, engage in exercise that you enjoy and will do often, and your bones, muscles and overall health will thank you for it!

SO, WHAT DOES THIS ALL MEAN?

Some key takeaways are:

  • Bone is more than just a structural organ; it releases hormones that directly influence our overall health and insulin sensitivity.
  • Bone-muscle talk is part of the puzzle researchers and exercise professionals need for building new treatments for the prevention, management and treatment of T2D.
  • How bone-muscle talk differs between men and women, and the role of sex hormones in bone-muscle talk, is very important and is still under investigation.
  • Consistent exercise is key for improving bone-muscle talk, overall bone and muscle health and prevention and management of diabetes.
  • Research on bone-muscle talk highlights that we should be paying close attention to our bone and muscle health, whether we’re at-risk of diabetes or not.
  • Regular exercise is crucial to our long-term health no matter what.

 

WHO TO TURN TO FOR HELP EXERCISING WITH DIABETES

It is always good to start with a medical clearance from your doctor and a conversation with an Accredited Exercise Physiologist if you’ve been diagnosed with diabetes or are at-risk of diabetes.

Accredited Exercise Physiologists (AEPs) are exercise professionals who are trained to help clients become more active and help them manage their diabetes better with exercise.  You can get a simple referral from your GP to an AEP in your area to get started and by doing this, you can also get Medicare rebates for seeing an AEP.

Find your local exercise professional today.

 

Written by Rhiannon Healy, Accredited Exercise Physiologist (AEP) and PhD candidate at the Institute for Health and Sport (IHES), Victoria University.

Rhiannon’s current PhD research project is investigating the sex-specific effects of exercise on bone-muscle interaction in individuals with T2D. If you’d like to know more about Rhiannon’s research or get involved in her study, reach out to her today.