Findings prove inactivity causes fragile bones


December 31, 2014

Topic: orthopaedic problems

Sitting on the couch truly may be bad for you. Researchers from the University of Cambridge have found that since the invention of farming, inactivity has caused people to have weaker bones.

Sitting on the couch truly may be bad for you. Researchers from the University of Cambridge have found that since the invention of farming, inactivity has caused people to have weaker bones. The study authors believe that the shift has something to do with our lives becoming increasingly sedentary with advances in technology and machinery.

A difference in age
The researchers, whose work was published in the journal PNAS, compared bones of humans from 7,000 years ago and found that their density was comparable to the modern day orangutan. They then compared those bones to farmers' bones from 6,000 years ago and realized they were significantly lighter. The scientists considered both body size and dietary changes and still found the same results. They discovered that humans who were hunters and gatherers had a bone density that was 20 percent higher than today's average person.

The study authors mainly looked at the femur, the longest bone in the body, and the femoral head, which connects the femur and the hip bone and bears much of the body weight. The bones examined ranged from the hunter-gatherers to modern day agriculturalists, who mainly sit for a living. All of the populations were from the same area within Illinois, noting that there may be somewhat of a genetic connection. The researchers stated that the bones in this area were much thicker for older generations than for recent ones. They believe the thickness was caused by the constant stress the humans put on their bones during hunting and gathering activities. The bones reached a peak point which helped them stay healthy in older age. The study authors noted that generations even older than 7,000 years had even better bone strength and density.

Problems for the future
The scientists noted that their results indicate that people are becoming less healthy and more prone to orthopaedic problems. They believe that this change is only getting worse, as people are becoming continually less active and not taking care of their bodies.

The researchers noted that their results show the importance of physical activity in relation to bone health. Proper exercise may be more important than diet in keeping bones strong and avoiding orthopaedic conditions such as osteoporosis that can cause fragility fractures. People who choose to exercise and keep physically active earlier in life are more likely to not have as dangerous of orthopaedic problems later on, the National Osteoporosis Foundation noted. It also stated that regular exercise should begin in childhood.

They noted that people today could most likely return to the bone density of our ancestors. However, the researchers stated that very little people have the daily active lifestyle that exerts enough stress on the bones that allows them to build to the density of hunter-gatherers. The researchers noted that people once relied on their bodies to survive. In the last 50 to 100 years, people have lost that need and been able to rely very little on themselves to meet their basic needs, given modern conveniences.

Signs of hope
The researchers noted we could return to our former state, but we need to challenge our bodies much more than we are right now.

"The fact is, we're human, we can be as strong as an orangutan - we're just not, because we are not challenging our bones with enough loading, predisposing us to have weaker bones so that, as we age, situations arise where bones are breaking when, previously, they would not have" lead author Colin Shaw of the Cambridge Research Institute said.

The study authors hope to continue their research on bone density and learn how different sports and levels of weight can affect bone health and its development. They want to include different types of athletes, such as marathon runners. They hope to pull bone data from older human species as well again.


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