Bicycle Network Victoria: Health Matters

Better vision on a bike?

24 January 2012. We all know that bikes are in our vision of a better future, but who knew that better vision is in your future on a bike?

According to a study by Cambridge University scientists every hour spent outdoors each week can reduce a child's chance of becoming short-sighted by two per cent.

Children who are short-sighted spend an average of 3.7 fewer hours a week outside compared with those with normal vision or are long sighted.

The positive effect from being outdoors appeared to be independent from the amount of time children spent reading or playing computer games, or to an increased amount of exercise, researchers said.

Between 15 and 20 per cent of British people are short-sighted but the problem is much more serious in parts of east Asia where as many as 80 per cent of the population is myopic.

One study comparing Chinese children living in different countries found that those in Australia had better vision on average than their peers in China and Singapore.

The Australian group read as much and achieved the same results academically as those in other countries, but tended to spend more time outdoors.

The review of eight studies by Dr Justin Sherwin and Dr Anthony Khawaja, covering 10,400 participants in total, was presented to the American Academy of Opthalmology.

Dr Sherwin said the benefit from being outdoors could be linked to increased exposure to ultraviolet light.

"It could be caused by not enough UV radiation, but it could also be spending less time looking into the distance or not enough physical activity."

Prof Paul Foster, who supervised the project, said: "It might be something to do with relaxing the focusing mechanism in the eye and returning it to normal distance vision, and the wavelengths of light we are exposed to outside could also have an impact."

Pedals push emotions higher

12 January 2012. A recent Deakin University study has found that higher levels of regular physical activity result in lifted emotions such as excitement, enthusiasm and alertness.

‘Physical inactivity has been linked to depression in clinical populations, and physical activity has been shown to be protective against developing depression," said School of Medicine’s Associate Professor Julie Pasco.

‘The aim of this our study was to examine the association between regular physical activity and any positive and negative effects on emotions.

‘The benefits of physical activity on general health and wellbeing are widely recognised, Associate Professor Pasco said, however, the mechanism of these effects are unknown,"

The study included 276 women aged 20 to 84 from the Geelong Osteoporosis Study, a population-based study being conducted by Deakin University’s School of Medicine, at Barwon Health.

Regular, or habitual, physical activity and other lifestyle exposures choices were assessed through a questionnaire.

‘Physical activity was categorised as very active, moderately active or sedentary’, Associate Professor Pasco said.

‘We determined positive and negative scores through something we called PANAS, the Positive and Negative Affect Schedule.

‘The results showed that higher positive affect scores, encompassing emotions such as interest, excitement, enthusiasm and alertness, are associated with higher levels of habitual physical activity.

‘The connection of physical activity with emotion appears to operate through enhancement of positive emotions, rather than diminution of negative emotions such as distress, anger and distrust.’

Associate Professor Pasco said this study, published in the Australian and New Zealand Journal of Psychiatry, warranted further research into the factors, both neurobiological and psychosocial, that cause the association.

Climate report pumps bikes

8 December 2011. Improving the design of cities and towns to make it easier to get around on foot and bike has the potential for substantial benefits to our health, economy and greenhouse gas emissions, according to the latest Climate Commission report.

The report cities research that estimates that current cycling levels save the Australian health system $22.72 million annually.

A New Zealand study found that a 5 per cent increase in short bicycle trips—less than 7 km—could have annual net health savings of NZ $200 million.

And a Scandinavian study found that the death rate in workers who cycled to work was 28% lower than for others.

The research is summarised in The Critical Decade: Climate change and health, by Lesley Hughes and Tony McMichael. The Climate Commission report to the Australian community on the latest science guiding climate change mitigation and adaption.

Hughes and McMichael report that physical inactivity causes over 13,000 deaths each year in Australia and increases the risk of heart disease, Type 2 diabetes, breast and bowel cancer, depression and anxiety.

In 2007-08, three in five adults and one in four children were either overweight or obese.

Increasing activity levels can prevent or limit these health disorders and thus save lives, and is an important part of combating obesity.

For example, increasing by only 5% the number of Australians who do 30 minutes of moderate activity each day, could save 600 lives a year.

According to the report Cycling and walking, in place of driving cars, can also help improve social connectedness and mental health.

Walking can improve mental health and wellbeing, by having a positive impact on self-esteem, physical self-worth, stress and mood. One study found that Australians who walked for recreation as little as about 10 minutes a day were 72% more likely to report better physical health and 33% more likely to report better mental health, than those who walked less.

Promoting cycling and walking in place of driving cars can also help reduce greenhouse gas emissions, the report says.

Transport generates 13% of Australia’s emissions, and is one of the largest sources of increasing emissions in Australia. Passenger cars make up about half of transport emissions.

Helmet protection confirmed . . . again

25 November 2010. A bike rider who crashes without wearing a helmet is five times more likely to suffer serious head injury than a rider with a helmet, according to an analysis of crash victims by Royal Prince Alfred Hospital (RPAH), Sydney.

The researchers compared the injuries suffered by more than 300 injured riders at the hospital between 2008 to 2010.

"Non-helmet wearers had five times higher odds of intracranial bleeding or skull fracture compared with helmet wearers," Dr Michael Dinh, the lead researcher, said.

The results are in line with similar international studies into whether helmets reduce head and brain injuries.

The findings are contained in a letter written by Dr Dinh and six colleagues at the RPAH's emergency and trauma departments, to the Medical Journal of Australia.

"It is the opinion of the trauma service at RPAH, based on these findings, that mandatory bicycle helmet laws be maintained, and enforced as part of overall road safety strategies," the authors say.

"The benefits of helmet use need to be placed in the context of lifetime costs of severe traumatic brain injury, estimated to be around $4.8 million per incident case."

The researchers also looked at the cases of almost 1000 riders who were injured in accidents going back to 1991.

During that time the number of riders presenting at RPAH emergency tripled, in line with the rising popularity of bike riding in Sydney.

But as the number of injured rider went up, their rate of serious head injury decreased significantly, from 10.3 per cent in 2005 to 2.5 per cent in 2009.

"The number of cyclists sustaining severe head injuries has remained consistently low over the long-term, with an apparent decline in the rate of severe head injuries in admitted patients since 2005," said Dr Dinh.

Helmet theory cracked by new study

16 August 2010. The theory that helmet laws stop people riding bikes has been contradicted in a new study by Canadian health researchers.

By studying the rate of helmet use in various provinces, some of which had no helmet laws, and some of which had introduced helmet laws in the study period, the researchers found that helmet legislation made no difference to the numbers of people riding bikes.

The conclusion was a surprise to many international cycling advocates, who have long believed that helmet laws resulted in fewer people riding.

Major cycling bodies, such as the European Cycling Federation and the CTC, the UK's bike organisation, have campaigned against helmets laws because they said they discouraged people from riding.

The new study,"The effects of provincial bicycle helmet legislation on helmet use and bicycle ridership in Canada", was conducted by four health academics, steered by Jessica Dennis, of McLaughlin Centre for Population Health Risk Assessment, University of Ottawa. The study was peer reviewed and published in the Journal of Injury Prevention.

The study reported that between 1994 and 2004, 44,577 hospitalisations occurred due to cycling incidents in Canada, representing 2% of all hospitalised injuries. Twenty-four per cent of these hospitalisations were due to head injuries.

A meta-analysis of five case-control studies of cyclists seen in emergency departments found that helmets significantly reduced the risk of head, brain, and severe brain injuries by 63-88% among cyclists of all ages.

The risk reduction was similar whether or not the crashes involved cars, or had other causes.

The release of the study comes at a time when there have again been calls for the repeal of Victoria's helmet legislation, amid claims that the rules are stopping the use of Melbourne BikeShare.

Bicycle Network Victoria has long monitored attitudes to helmet wearing and has concluded that it has become normalized in Victoria, where the rates of Helmet wearing are extremely high -- and significantly higher than Canadian provinces with helmet laws.

Helmets are accepted as a part of everyday riding and the proportion of riders who object to helmets is now tiny.

Good riding environment lifts emotional health

13 May 2010. If you are feeling buoyant after pleasant ride down a country trail, you are not imagining it; a study says the benefits are real.

The researchers set up an experiment where riders were placed on a treadmill in front of a screen where images of riding environments were projected.

Various riding environments were simulated—rural pleasant, rural unpleasant, urban pleasant and urban unpleasant—and physical and emotional indicators were measured.

Even in the simulated environment, there were striking differences in the effect of the exercise, depending on the type of environment in which it was taken.

The study, titled 'The mental and physical health outcomes of green exercise' was undertaken by Jules Pretty, Jo Peacock, Martin Sellens and Murray Griffin at the Department of Biological Sciences at University of Essex, UK. It was published in the International Journal of Environmental Health Research.

They say: "There was a clear effect of both exercise and different scenes on blood pressure, self-esteem and mood. Exercise alone significantly reduced blood pressure, increased self-esteem, and had a positive significant effect on 4 of 6 mood measures.

"Both rural and urban pleasant scenes produced a significantly greater positive effect on self- esteem than the exercise-only control. This shows the synergistic effect of green exercise in both rural and urban environments.

"By contrast, both rural and urban unpleasant scenes reduced the positive effects of exercise on self-esteem. The rural unpleasant scenes had the most dramatic effect, depressing the beneficial effects of exercise on three different measures of mood.

"It appears that threats to the countryside depicted in rural unpleasant scenes have a greater negative effect on mood than already urban unpleasant scenes.

"We conclude that green exercise has important public and environmental health consequences."

The paper is available here.

Bikes and public health on US agenda

29 April 2010. The US government is moving to explicitly measure the health benefits of bike riding in order to place bike exercise at the centre of public health policy.

The Centre for Disease Control has gathered expertise from around North America to work on the project, including leading bike transportation analyst, Todd Litman.

"Although I’ve worked on this issue for years, I did not fully appreciate the magnitude of these benefits until I participated in a special workshop to produce a U.S. version of the Health Economic Assessment Tool (HEAT), a science-based computer model developed by the World Health Organization that calculates the value of health benefits of increased cycling activity", Mr Litman wrote.

"I learned a lot. Current research indicates that regular doses of moderate physical activity provide these benefits:

• 50% reduction in the risk of developing coronary heart disease (similar to not smoking)
• 50% reduction in the risk of becoming obese
• 50% reduction in the risk of developing adult diabetes
• 30% reduction in the risk of developing hypertension
• For people with hypertension, blood pressure reductions comparable to costly drugs
• 20% reduction in common forms of cancer (breast and colon)
• Helps to maintain bone mass and so protects against osteoporosis
• Improves balance, coordination, mobility, strength and endurance
• Relieve symptoms of depression and anxiety, and increases self-esteem and overall psychological wellbeing."

Mr Litman said a transportation policy or project was worth far more than generally recognized if it increases walking and cycling activity.

"This has important implications for decisions such as roadway design, traffic calming, investments in sidewalks and paths, and land use policies that affect the amount of nonmotorized travel that occurs in a community," he said.

The full analysis is on Mr Litman's blog here.

Doctors should back improvements for riders

21 April 2009.

Much more needs to be done in Australia to provide an environment that encourages people to cycle safely, the Medical Journal of Australia says.

Physicians should support efforts to win better riding facilities as well as recommending that patients ride, according to Australia's premier medical journal.

In an editorial on April 6 the Journal argued for greater funding and a community priority to allocate road space for cycling.

"Despite the perceived risks of cycling, the absolute magnitude of the risk is low, and the benefit-to-risk ratio is is overwhelmingly positive; for chronic disease prevention, obesity reduction and mental health the benefits are substantial," the Journal said.

"Cycling provides an affordable, convenient and achievable form of physical activity for all Australians, including children and youth, through to older adults with chronic conditions.

"As a physical activity, it also meets transport and traffic management needs and is eco-friendly."

The Journal said it was generally understood what needed to be done to increase cycling participation levels.

"Better urban design, such as higher density development, mixing residential and commercial land use, and shorter trip distances, will facilitate more cycling."

In the editorial the Journal argued against the concept of requiring bike riders to be registered.

"It would cost more to administer than it would recoup, and it would likely act as a significant deterrent to casual or occassional cycling."

The Journal said that making cycling safer required better infrastructure and facilities for cycling, especially the provision of separated bicycle paths and bicycle lanes.