A Finnish study reports that older women who exercised just 20 minutes per day were much less likely to sustain bone fractures than inactive women. The authors say that increasing physical capability by just a little bit can mean the difference between injury and safety.

Five women in the control (non-exercising) group had hip fractures, while the exercisers never suffered one.

All 100 women in the study suffered from osteopenia, a precursor to osteoporosis, in which some amount of bone density has already been lost. The women attended an exercise class that focused on balance, strength, and impact training, and they were asked to practice for twenty minutes per day on their own time. The researchers, led by Raija Korpelainen, followed the women for 7 years. The control group did not take part in this exercise regimen.

They found that the women in the exercise group suffered fewer fractures than the women in the control group: 17 vs. 23, respectively. The types of fractures in the two groups also occurred in different parts of the body, with fractures happening further from the body in the exercisers. The authors write that people who exercise are probably better equipped to withstand a fall and avoid hip fracture. In fact, five women in the control (non-exercising) group had hip fractures, while the exercisers never suffered one. Interestingly, the exercisers were also less likely to die during the follow-up period (one exerciser vs. eight in the control group died during follow-up).

The authors also point out that the energy or "performance" reserves of elderly people are often not large, so that "even a small additional decline in balance or strength can cause serious difficulties." They say that even increasing one’s energy or performance ability just a little bit can be enough to help a senior "maintain independence".

As a rule of thumb, they recommend that seniors be able to walk 300 m comfortably, or the equivalent of about 1,000 feet. Another guideline is to be able to walk about 1.1 meters/second, which is enough to cross the street safely — earlier studies have found that walking just a little slower than this (1 meter/second) was linked to more health problems. But before beginning an exercise routine, it is important talk to your doctor about a safe way to begin and to get the most benefit out of it.

The study was published in Archives of Internal Medicine, and executed by researchers at Oulu Deaconess Institute in Oulu, Finland.