Bone is a living tissue that, like all tissues in our body, replaces itself over time. By the age of 30, the average person will have replaced the complete skeleton up to 5 times.
The replacement of bone tissue is mainly carried out by two types of cells: osteoblast and osteoclasts, which are both variants of osteocytes, and perform different functions within the bone life cycle. Osteoblasts are the cells responsible for the bone cell production, while osteoclasts are the cells responsible for the breakdown and bone reabsorption. These cells work in tandem to continually remodel our bones as we grow at different rates through our lives. It is the relationship between these two cells that produce bone density as an outcome.
Bone density is influenced by several factors, some of them are intrinsic (we cannot change them) like age, gender, race, and genetics, while some are extrinsic (can be changed) like calcium in diet, physical activity, tobacco, alcohol consumption, eating habits and medication.
Our peak of bone density occurs once the rate of new bone being remodel by the osteoblast is greater than the rate of breakdown by the osteoclast. However, with age and other factors, this relationship will shift, resulting in a decrease of bone density. When the bone density is too low, the risk of osteopenia, osteoporosis and eventually bone fractures will increase.
A combination of osteoporosis + poor balance + loss of muscle mass and strength = high risk of fracture
What can I do to keep my bones healthy?
Osteoblast, the cells responsible for remodelling the bone and increasing bone density, respond to mechanical stress through the axial plane and growth factors such as hormones. Weight bearing activities will cause the mechanical stress through the axial plane. Researchers from the Bone & Joint Injury Prevention & Rehabilitation Center at the University of Michigan have identified several characteristics of exercise that have an impact on bone density through mechanical stress:
How can LEAR help?
However, exercise is not the only way to take care of your bones and maintain a healthy bone density:
Jennifer Kellett, Oct 5, 2017, The stages of Osteoporosis, Hawker Place Physiotherapy and Pilates: