The Effects Of Exercise On Bones

I'M ONLY 31 BUT HAVE THE BONES OF A 70-YEAR-OLD

AT THE age of 14 when most of his peers were playing computer games or watching football John Evans was pumping iron. After suffering years of cruel taunts at the hands of playground bullies John was desperate to lose his puppy fat.

“It was horrible,” he says. “From the age of eight, I was called ‘doughnut’ and ‘whale’. It was my friends who were doing the name calling. We’d be playing football and they would all turn on me because I was bigger than them.”

In his mid teens he decided to take matters into his own hands and shed his excess pounds.

“I’d get off buses early so I could walk and started going to the gym. I began to hide some of the food my mum gave me for school and eat smaller portions of everything. When I lost some weight, the bullying tailed off.”

However as the jeering stopped John’s preoccupation with exercise and being the thinnest at school remained with him. It was the beginning of a 17-year battle with the eating disorder anorexia nervosa which left John with serious long-term health problems.

“By the time I was 16, I started being more aware of the calories in food. I could eat things only if I knew exactly how many calories were in them so I knew how much exercise to do to burn them off.”

When John left home to go to university at 18, and lived away from his family for the first time, his problems began to spiral out of control. “I played football, tennis, went to the gym, did circuit training, walked everywhere and up every flight of stairs. I only ate a small bowl of cereal, an apple and a tiny portion of dinner every day.”

Six weeks after starting his course John’s father visited and found him looking pale, drawn and tired. He agreed to see a doctor where he was diagnosed with anorexia. His weight had fallen to 8st, too low for his 5ft 7in height.

“I had a weird reaction to the diagnosis. I was actually relieved.

“No one could say I was fat if I was anorexic. My family and friends were fantastic, they were so supportive but they completely missed the point.

“They wanted to understand anorexia but how could they? This disease makes no sense at all. You want people to help you but at the same time you just want to be left alone. They would make me eat and I’d never felt less willing to do so. It was horrific. I decided I was going to be very good at being an anorexic.

Physical activity and bone quality | Medicographia

Physical exercise acts directly on bone through mechanical stress, and indirectly by changes in cardiovascular, ventilatory, metabolic, and hormonal parameters. Studies in athletes show that activities such as running, performing gymnastics, and weight lifting induce bone gain, whereas cycling and swimming are poorly osteogenic. Bone gain is mostly observed in the parts of the body involved in the exercise. Failing to continue exercising during adulthood could be detrimental to bone gain. In the early stages of puberty, exercising increases bone mass, whereas in postmenopausal women and in the elderly, exercise does not always provide bone gain. Nevertheless, it may prevent osteopenia and improve muscle tone, cardiovascular function, and balance, thus limiting the risk of falling. As is the case for some young people, too much training can be harmful, as evidenced by cortical thinning in older cyclists who train more than 6 hours per week. This is evidence of a nonlinear effect of exercise on the skeleton. High-impact exercises are hardly applicable to fragile subjects. Whole-body vibrations (WBV) may have osteogenic potential. In animal models of bone loss, WBV improves bone mass and quality. In humans, certain studies show a potential benefit of WBV with regard to muscle, bone, and posture. The therapeutic use of WBV is not standardized, and the impact and scope of application still needs to be defined in terms of frequency, amplitude, duration, etc. This will require tailoring WBV to the characteristics of the users and assessing its effect on the whole body as well as on individual compartments (cartilage, peripheral circulation, tendons).