I was at the hospital recently and happened to mention in a conversation with a nurse there that I was not wearing a helmet during summer due to the heat. I am not convinced of the efficacy of helmets, especially in situations where you may get run over a car or truck, most of my riding is offroad and very low risk and helmets are so hot in summer that I decided that the increased risk was minimal. She countered with a statement that, having worked in casualty, she noticed a huge difference in injuries since helmet laws came into force, she agreed that in the case of being run over the head by a car they were not much use but that there has been a change in injuries since the helmet laws changed. Then she looked away, went back to her paperwork and did not want to engage in further discussion, so I just mumbled something about the research being very divided on the helmet issue and left.
This conversation unsettled me however, and I was not sure why till today when I had more time to think it over. Firstly, her reasoning was unclear, were there fewer injuries or were they less bad due to helmets? Australia is one of the few places with mandatory helmet laws, and mandatory helmet laws have contributed to a decrease in cycling rates for a variety of reasons and this usage reduction could well be the reason for the reduction in injuries. (Travelling in cars also carries a very real risk but that is a debate for another time.)
Australia also has the highest level of obesity in the world, it is evident everywhere here and is well documented, and this is also related to the reduced rate of cycling. I have never heard any health professional say to someone that their sedentary lifestyle/obesity is a huge risk, although I am sure that they must encounter the health effects of this situation nearly every day. I have encouraged others to cycle to work, and the helmet hair issue is a factor for some of them, as are hills, traffic, perceived danger etc. I have been encouraged by my doctors to cycle as they see the effects of lack of exercise in their patients. I do not find it easy to ride the hills I encounter but I persist and push the bike if necessary. It is a matter of balancing the risk with the benefits, and I choose to cycle whenever I can, sometimes without a helmet.