Mountain biking is great for you, until you do too much of it. And by too much, I mean you’re cycling and doing a whole bunch of nothing else. Unfortunately, cycling-only fitness routines can lead to the loss of bone strength.
About.com spoke with Michael A. Smith, M.D., senior health science specialist at Life Extension Foundation, Fort Lauderdale, FL, and James Ting, MD, FAAFP, board-certified Primary Care Sports Medicine physician at Hoag Orthopedic Institute, Irvine, CA, about bone density and what you can do to prevent vulnerability.
About.com: What is bone density?
Dr. Smith: It refers to the amount of mineralization of your bones primarily made up of the minerals calcium, magnesium, boron and manganese. It’s used as an indicator of bone strength and flexibility.
About.com: Why is preventing bone loss so important?
Dr. Smith: Low bone density or osteoporosis is associated with fractures. Fractures of the hip or long bones in older women, for instance, are associated with a greater than 50% mortality rate. Osteoporosis makes bones more susceptible to fracture, most often of the wrist, spine and hip. Spinal fractures cause stooped posture, loss of height and chronic back pain. Hip fracture, the most serious consequence of osteoporosis can threaten an individual’s independence and life.
Dr. Ting: Preventing bone loss is important in regards to preventing fractures. There is significant morbidity in regards to pain, disability and diminished quality of life secondary to osteoporosis-related fractures. There is in some cases the chance of a significant associated mortality, particularly in regards to hip fractures.
About.com: Why is bone health so important in athletes?
Dr. Smith: Healthy bone density reduces the risk of soft tissue and joint injuries. Strong bones are absolutely integral to your success as an athlete. Your skeletal structure provides the strength and rigidity that allows you to train and compete in your sport. Ask any athlete that has suffered a stress fracture: When the health and integrity of your bones is compromised, so too is your ability to perform athletically.
Exercise puts a positive stress on bone, and just like with muscle, your bones generally respond by becoming stronger. But some athletes are actually at high risk for weak bones and stress fractures.
Dr. Ting: Bone health is particularly important in regards to young female athletes. The years of peak bone mass typically occur by age 18 in females. Overtraining in addition to inadequate nutrition or disordered eating can result in what can be referred to as an energy deficit. This energy deficit has a significant impact on various endocrine/hormonal pathways which may result in decreased bone density. Clinically this can manifest as stress fractures and/or ultimately early osteoporosis. This has been commonly referred to as the Female Athlete Triad.
About.com: How can exercise prevent osteoporosis?
Dr. Smith: Exercise is one of the best methods for improving bone density. Specifically, weight-bearing exercises increase bone mineralization.
A key measure of the health of your bones is how much mineral, i.e. primarily calcium and phosphorus, can be found in them. Called bone mineral density or bone mass, the greater the density, the stronger your bones, and the less chance you have of suffering a stress fracture during exercise or a fracture later in your senior years.
About.com: What are the best exercises for building bone?
Dr. Smith: Weight-bearing exercises. Studies suggest that higher-impact, weight-bearing sports and activities prior to and during puberty seem to be most effective at building stronger bones. Activities that involve jumping are particularly useful. Thus, a key strategy for helping to ensure a lifetime of strong bones is to maximize bone mineral density during the adolescent growth spurt and in early adulthood by encouraging regular participation in a variety of physical activities and sports.
Dr. Ting: In adults, aerobic, low-impact exercises, such as walking or jogging, are best. Weight-bearing exercise performed in 45 to 60 minute sessions three to five times per week is recommended.
About.com: When exercising, why is it important to ensure you are using the proper technique?
Dr. Smith: Poor technique, especially with weight-bearing exercises, can lead to injury and in some cases long bone and hip fractures.The good news is that all the exercise you’re doing can stimulate the building of stronger bones. The bad news is that certain athletes have low bone mass or sports osteopenia. This is all too commonly diagnosed in female athletes. As a consequence, they are at high risk for stress fractures during exercise. A stress fracture is a partial or complete break in the bone. It’s caused by the bone’s inability to withstand repeated stress of a non-violent nature, such as running. Stress fractures occur because microscopic damage in the bone accumulates and is not adequately repaired by the remodeling process. An increase in the load on a bone can cause a stress fracture. In addition, factors that interfere with bone remodeling and repair, or those that decrease bone strength, are culprits.
About.com: Please feel free to include anything else about maintaining bone health.
Dr. Smith: Even if you live a healthy lifestyle, we need to see our doctor for routine checkups, especially as we age. If left untreated, osteoporosis and other bone density problems can lead to disastrous consequences, including disability and even death. Visiting the doctor routinely can help you develop a personalized strategy for maintaining bone density.