Exercise and Childhood Bone Health
A Lifetime of Healthy Bones
The life expectancy of today’s population has increased considerably from what it was fifty years ago. With the population getting older we see more and more people developing age related diseases like osteoporosis. Osteoporosis is the progressive loss of bone over time, making bones more prone to fracturing, and it is a costly and debilitating disease affecting much of the world’s population. You might be thinking: Why am I reading about osteoporosis in a child health magazine? The answer is simple. The best way to decrease the risk of developing osteoporosis is by ensuring that you start off in life with your bones being as strong as possible. As the rate of bone development is highest during childhood, it is important to understand how changes in bone health during childhood can delay the onset of osteoporosis.
Bone strength is influenced to varying degrees by genetics, diet and exercise. For instance, boys are genetically designed to have stronger bones than girls because they have bigger muscles that make it so. This does not mean that girls can’t ‘catch up’ as long as they know how to improve their bone strength. The first step is to make sure that your child has the building blocks they need to add on to their bones. Bones need lots of calcium vitamin D during their rapid growing phases. The sun takes care of the vitamin D and foods like fresh fruits, vegetables and milk ensures that your child has enough dietary calcium for strong bones. After that, your child has to tell his or her body where it should put these building blocks. Everyday physical activity tells the body where the calcium and vitamin D are needed.
As an adult, 90% of your bone mass is developed during the years preceding puberty with bone growth typically at its greatest between the ages of 11 and 14 years. This would be the ideal time for an intervention that will optimize bone growth. Bone growth slowly declines after the age of 16 and stops during the mid-twenties. Growing bones are more elastic and so physical activity is especially important during the pre-pubertal and pubertal years. It will influence the natural growth of bones, changing their shape and making them stronger. With technology developing at a rapid pace, a child’s play time consists of much less active play and more sedentary activity. Television, tablets and cellphones are now the normal pastime but how is this affecting your child’s health? Children are participating in less physical activity, which is not only detrimental to bone development but also increases their risk of developing heart disease and diabetes in later life.
The best way to strengthen bones during childhood is through participation in physical activity. Specifically exercises which place weight on the bones. In the world of science we call them weight-bearing exercises. Bone is a living tissue where bits of old bone is constantly being removed and replaced with new bone. These constant changes occur because bone adapts in response to strains and stresses placed on it. Bone adapts to physical activity on both an internal and external level. Internally exercise stimulates changes to the mineral composition of bone so that more calcium is laid down and the bone becomes denser. Externally, the forces exerted on the bones by muscles or by the weight they need to support causes changes in the surface geometry of bone. Bones become bigger and thicker as a result.
The big question would then be: Which exercise is best for my child’s overall bone health? Firstly, if your child does not participate in any organized sports, then something as simple as playing soccer in the back garden or jumping rope would be a great place to start. If you are interested in something more competitive, then sports like tennis, basketball or gymnastics are your best options. These exercises are all considered weight-bearing exercises involving the upper and lower limbs and target all the bones of a growing child, including the spine. An exercise like swimming is not considered weight bearing but that does not mean it won’t contribute to the development of strong bones. Swimming, as with other forms of exercise, still contributes to the growth of muscle. Muscles place stain on bones and in response the bone is stimulated increase its size and density to be able to resist the strain provided by the muscles and tendons. Therefore larger muscles also mean stronger bones.
Children should be motivated to participate in at least one form of physical activity. It will strengthen their bones and decrease their risk of fractures related to osteoporosis in later life. By obtaining the maximum possible bone density during childhood, you could extend the onset of osteoporosis by 13 years! So tell your kids to start jumping, running, skipping, swimming, hula-hooping, chasing, fetching, catching and playing – it will set them up for life!
