Bone is living tissue that is constantly undergoing a process called remodeling. In remodeling, cells called osteoclasts are breaking down old bone, as cells called osteoblasts are replacing it with new tissue. Many factors can affect the remodeling process and leave you with bones that are less dense and more fragile.
Some factors that interfer with bone remodeling are:
Regular weight-bearing and resistance exercise helps build muscle, as well as maintain and increase bone strength. Exercise causes the muscle to contract against the bone. This action stresses or stimulates the bone, and the bone becomes stronger and denser. The 3 main types of exercise are (some activities can be more than 1 type):
In aerobic exercise, you continually move large muscles in the legs, shoulders, and buttocks. This action causes you to breathe more deeply, and your heart to work harder pumping blood, thereby strengthening your heart and lungs. Examples include:
In weight-bearing exercises, your bones and muscles work against gravity, and your feet and legs bear the weight. Your bones adapt to the weight and pull of the muscle during weight-bearing exercise. Examples of weight-bearing exercises include:
Resistance exercises use muscle strength to improve muscle mass and strengthen bone. Examples include:
Before starting any type of exercise program, check with your doctor about any possible medical problems you may have that could limit your ability to exercise.
National Osteoporosis Foundation
The President's Council on Physical Fitness, Sports, and Nutrition
Canadian Orthopaedic Foundation
Public Health Agency of Canada
2008 Physical Activity Guidelines for Americans. US Department of Health and Human Services website. Available at: http://www.health.gov/paguidelines/guidelines/default.aspx#toc. Published October 2008. Accessed January 21, 2016.
Bone remodeling. University of Washington website. Available at: http://courses.washington.edu/bonephys/physremod.html. Updated March 30, 2007. Accessed January 21, 2016.
How much physical activity do adults need? Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/physicalactivity/everyone/guidelines/adults.html. Updated June 4, 2015. Accessed January 21, 2016.
Osteoporosis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated October 13, 2015. Accessed January 21, 2016.
Skeleton keys. Smithsonian Museum of Natural History website. Available at: http://anthropology.si.edu/writteninbone/young_old.html. Accessed January 21, 2016.
Last reviewed January 2016 by Michael Woods, MD Last Updated: 2/12/2014