Bone Health – Are You Doing Enough?
Are you doing enough in your workouts to promote strong bones?
I am frequently asked if doing “just Essentrics” or “just walking everyday” is enough to keep bones strong. The answer: it depends. If you have been sedentary for a long time, almost any type of fitness regime will help you get fitter and start to strengthen your bones. If you’re already active, the question should be are you doing enough to promote bone health? Are all your bones being challenged enough to prevent breakdown and to get stronger?
Let’s start by looking at what bone density is.
The minerals calcium and phosphorus are largely responsible for the hardness of your bones.1 Bone mineral density (BMD), is the amount of these minerals (and others) in bone tissue. 2 The higher your bone mineral content, the denser your bones are. And the denser your bones, the stronger they generally are and the less likely they are to break.3
Bone loss that becomes medically concerning (like osteopenia or osteoporosis ) can lead to an increased risk of fractures. The ribs, wrists, hips and spine are the most common places to lose bone density and experience bone-loss related breaks.
The causes of bone loss are many. Risk factors include: lack of physical activity, smoking, menopause, low calcium intake, having a petite body frame and hereditary factors.1
Aging is also strong factor in bone loss. Beginning around age 34, the rate of bone loss can exceed the rate of bone formation, leading to an inevitable loss of bone mass. Age-related estrogen reduction contributes to loss of bone mass over time as well. The first three to five years following the onset of menopause are associated with an accelerated loss of bone mass at a rate of two to six times the premenopausal rate.4
The good news is that we can make our bones stronger by becoming more physically active.
“Bone forms in areas of stress and is resorbed in areas of non-stress.” In other words, the more bones are stressed by mechanical loading during physical activity, the more they increase in volume and mass, specifically at the site of mechanical loading.1 Likewise, if you don’t place any demands on a bone, the bone tissue will weaken over time.
Wolff’s Law tells us that bone formation is heightened in those areas where the stress is targeted. Do squats and the leg bones strengthen, not the arms. Do push ups and the wrist and arm bones strengthen, not the legs. Our bones adapt to the loads they are placed under. If you don’t regularly challenge your bones with increased physical activity they will break down.
Weight-bearing VS Resistance training exercise
Weight-bearing exercises are exercises where the body works against the force of gravity and where body weight is supported through the feet and legs or hands and arms to carry the person’s weight (as opposed to swimming where the body is suspended). Exercises where only the body is utilized (working against gravity) such walking, hiking, jogging, climbing stairs, playing tennis, doing push ups and dancing are considered weight-bearing. Essentrics is a perfect example of this. We are moving the body in a multitude of ways, using our body weight as our resistance, fighting against gravity.
Resistance training is any exercise that causes the muscles to contract against an external resistance. The external resistance can be dumbbells, exercise tubing, your own body weight, bricks, bottles of water, or any other object that causes the muscles to contract.
When you do weight-bearing or resistance training exercises that are more intense than what your muscles come to expect (like lifting more than your purse), the tendons that attach muscles to bone, pull on your bones stimulating the bones to respond. This is mechanical stress. We can use our body weight to stress the bones and we can use external equipment too.
Please note that if you’re only doing weight-bearing exercises where you’re standing (walking, hiking, etc) you may be missing the benefits of loading your upper body on your hands or forearms (like doing pushups and planks) or with external resistance (using bands or dumbbells). This upper body weight bearing is very important for strengthening the smaller bones of your upper body.
What does science tell us about exercise and bone health?
Research is quite clear that exercise, be it weight-bearing and/or resistance training can improve bone health. However, some forms seem to be more bone-building than others. According to research done by Hong and Kim6 and presented in their paper “Effects of Resistance Exercise on Bone Health“, the following exercise choices should be considered:
- Low-impact non-weight bearing exercises such as swimming and cycling have little effect on bone building.
- Low-impact weight bearing exercises such as walking has mild effects, but overall is insufficient to optimize skeletal health.
- Moderate- to high-impact or multi-directional weight-bearing activities have been shown to maintain or improve bone health. Examples include running, jumping, dancing. Essentrics would fall in this category.
- High-impact non-weight-bearing exercises, such as progressive resistance training, has a greater mechanical load and leads to increases in bone strength. According to the researchers, resistance training may be the most optimal strategy to improve the muscle and bone mass in postmenopausal women, middle-aged men, or even the older population.
***Please note that swimming, cycling and walking have other very important benefits such as improving your cardio-vascular health.***
How often should I train?
According to the Canadian Guidelines for Physical Activity 5, to achieve health benefits, adults of all ages should accumulate at least 150 minutes of moderate to vigorous intensity aerobic physical activity per week, in bouts of 10 minutes or more. The guidelines also state:
It is also beneficial to add muscle and bone strengthening activities using major muscle groups, at least 2 days per week.
Overall, studies suggest that weight-bearing and resistance exercise training play an important role in maximizing bone mass during childhood and adolescence, maintaining bone mass through adulthood, lessening bone loss with aging, and reducing falls and fractures in the elderly.1 Studies are numerous in demonstrating that resistance workouts for menopausal and post-menopausal women can slow down and even halt bone loss.
It is imperative that we regularly exercise in such a way that all bones are stressed to keep them strong. As we age we need to be vigilant about our overall health in general and our bone health in particular.
1- Plowman, S.A. & Smith, D.L. (2011). Exercise Physiology For Health, Fitness and Performance. Baltimore, MD. Lippincott Williams & Wilkins.