By Dr. Emilia Ravski
Exercise has many benefits! There is much discussion on how regular exercise
can improve cardiovascular endurance, increase strength and maintain a
healthy weight as well as prevent many diseases such as diabetes and high
However, we cannot forget about our bones! How many people actually think
about exercising to strengthen bones or prevent fractures? There are many
reasons why it is important to have strong bones. Bones not only serve
as a framework for our body, but also have essential roles such as protecting
vital organs, making blood cells and storing minerals. Unhealthy bones
can lead to fractures which may result in significant morbidity and limitations
in daily activities.
Yes, nutrition including appropriate amount of Calcium and Vitamin D intake
are key components of good bone health. Additionally, exercise has been
shown to be an important factor in building and maintain strong bones!
Throughout our lives, bones go through a remodeling process where old bone
is removed and replaced by new bone. Cells within the bone called osteoclasts
work to breakdown bone and cells called osteoblasts build bone. This remodeling
process is important for maintaining calcium homeostasis, shaping the
skeleton during growth and repairing damage caused by daily stress. Under
appropriate amount of force, the bones thicken at the point of maximum
stress resulting in stronger bones. The balance is offset toward bone
breakdown with aging, nutrient depletion, certain medications and disease
processes. It is imperative to manage modifiable factors for weak bones
in order to optimize bone development and minimize bone breakdown.
So when should we start thinking about our bone health?
Well, the highest rate of bone development is seen in young children and
in early teen years, with more than 90% of peak bone mass achieved by
age 18. Peak bone mass refers to the maximal density of bone that will
be attained during our lifetime. This is determined by genetic factors
along with nutrition, hormones and physical activity. Thus, the bone density
that we have at age 18 and into our early 20’s is the highest in
our lifetime! As we advance into adulthood the rate of bone formation
decreases and bone breakdown increases. The bone mass in adults equals
the peak bone mass at age 18-25 minus the amount of bone subsequently
lost. It is therefore critical to emphasize healthy eating and exercise
habits in children and adolescents to ensure development of maximal peak
bone mass. The U.S. Department of Health and Human Services recognizes
this as a key aspect of growth and has initiated a campaign called “Best
Bones Forever”. The goal of the campaign is to educate and implement
healthy eating and physical activity habits that are important for a child’s
health and bone development.
Progressing into adulthood, it becomes important for pre-menopausal women
to maintain bone density that was achieved in their younger years. Estrogen
plays a key role in bone health in women and plays in our favor. Estrogen
is protective to bones because it inhibits osteoclasts which break down
bone and keeps the bone turnover process balanced. In addition, regular
weight bearing exercises that load the bone can also help maintain bone
strength and minimize bone loss in adulthood.
At menopause, estrogen levels drop and the balance of bone turnover is
altered leading to increased rate of bone removal in relation to bone
formation. This transition results in weakened architecture, low bone
mass and can lead to osteoporosis. Osteoporosis is the most common disease
of the bone that affects both women and men. It is characterized by low
bone mass with disruption of normal bone architecture, making the bones
more susceptible to fracture. This is concerning, as the elderly patient
may already be at an increased fall risk due to other medical conditions
or deconditioning. In the United States 1.5 million osteoporotic fractures
occur annually. The staggering data is that 1 in 2 of Caucasian women
will suffer an osteoporotic related fracture in her lifetime. This information
highlights the importance of imposing measures for achieving maximum peak
bone mass at a young age and preventing bone loss and falls throughout
Although osteoporosis does have a genetic component, it is preventable
and treatable especially when diagnosed early. The first line approach
to prevention and treatment includes elimination of risk factors that
lead to poor bone health such as inactivity, smoking, alcohol, caffeine
and low Vitamin D and Calcium levels.
In terms of exercise, the general recommendation by the National Osteoporotic
Foundation for prevention of osteoporosis includes regular weight bearing
and muscle strengthening exercises to reduce bone breakdown, risk of fractures
and falls. Weight bearing exercises are those where muscles contract against
gravity with the feet and legs supporting the body’s weight. Examples
include walking, jogging, jumping, Thai Chi and dancing. Muscle strengthening
exercises include weight training or other resistance training methods.
Examples include lifting dumbbells, using weight machines or resistance
bands, Yoga, and Pilates. One study evaluating the relationship between
bone mineral density and exercise showed that Senior Olympic runners over
the age of 65 had significantly greater bone mineral density compared
to non-athletes of similar age. This is encouraging and supports the notion
that certain exercises can potentially counteract the typical age related
bone loss in adults in addition to improving strength, posture and balance.
The Best Exercises for your Bones
We know that exercise is good for our overall health including our bones.
But, what are the best exercises and how often should they be performed?
The answer to this question will vary depending on the individuals’
age, cardiovascular fitness and associated comorbidities. There are general
guidelines in place with recommendations for exercise in children and
adults. For example, the Center of Disease Control recommends that children
and adolescents incorporate impact activity such as running and jumping
into their daily exercise in order to build strong bones.
The general recommendation of weight-bearing exercises and resistance training
for maintaining bone health also applies to pre-premenopausal women. However,
in this population regular physical exercise may not be enough to improve
bone mineral density. Rather, as demonstrated by several studies, higher
impact exercises such as jumping, jump rope and plyometric exercises may
be necessary as these correlated with greater improvements in bone mineral
mass when performed regularly.
The positive effect of exercise on bone growth is diminished in post-menopausal
women due to increased rate of bone breakdown. There is evidence to suggest
that a combination of resistance and weight bearing exercise in post-menopausal
women can improve bone density and prevent falls. The type, intensity
and frequency of exercise, especially for the elderly, needs to be catered
to each individual based on their age, fitness level and medical history.
Before starting a vigorous exercise program, a physician’s evaluation
and clearance is recommended.
In summary, it is critical to achieve a high maximal peak bone mass in
children and young adults, and also maintain healthy bones throughout
adulthood. This can be accomplished by eliminating factors that cause
bone breakdown and incorporating regular exercises that include a combination
of weight bearing and resistance training.
Read More at Prevention.com, where Dr. Ravski was recently featured:
4 Best Exercises for Strong Bones