As a kid, I loved to bike. On my two-wheeler, I could zoom far beyond my neighborhood to deliciously unsavory places where my parents forbade me to go. When as an adult I moved to Manhattan, where driving a private car is problematic, I again took to the bike as a convenient mode of transportation free of subway and bus schedules.

But several incidents over the years got me off the streets. First, there was the taxi driver who swerved in front of me as I toiled up Manhattan’s 6th Avenue during my fifth month of pregnancy. “Ya know, lady, ya can get knocked down too!” he bellowed out his window. Then there was the time that another cyclist veered right up to me in Central Park and pinched my bottom, really hard. I gave chase but drove over a pothole, toppled and wound up with a bad case of road rash.

All that made me realize that bikers, especially klutzy ones like myself, are out there, unprotected — from the elements, from drivers and from other bicyclists who sometimes, in their war against the wind, the snow and the traffic, take on the ethos of a Mad Max. 

You’ve got to say, however, that cyclists are valiant. After all, they are making a personal effort to reduce carbon emissions and pare our reliance on fossil fuel. Plus, they develop awesomely muscled thighs and rears that add to our enjoyment of the cityscape.

Their brains are bulked up, too. Danish scientists testing how well schoolchildren perform when they eat a solid breakfast and lunch recently reported that how the kids got to school was more significant than what they ate. Those who biked or walked performed better than those who rode in cars or took public transportation. Niels Egelund, a co-author of the study, said: “As a third-grade pupil, if you exercise and bike to school, your ability to concentrate increases to the equivalent of someone half a year further in their studies.”

Brain power

Bicycling seems to work well on aging brains, too. A UCLA study found that people aged 65 to 69 who were most active (via walking, swimming and biking, of course) had 5 percent more gray matter than those who were least active. Gray matter, aka the cerebral cortex, processes much of the information we use, and its shrinkage contributes to senile dementia.

But biking is still dangerous. For starters, there are traffic accidents. In 2011, the last year for which statistics have been reported, fatalities among bicyclists around the country rose by 8.7 percent over the previous year to 677. Some 48,000 cyclists were injured. That’s 4,000 fewer than the previous year, but still a massive number.

Minnesota has performed much better than the nation as a whole. According to MNDOT, while bike riding is up, fatalities in the state have dropped. In 2011, four bicyclists were killed, the lowest number since 2007. Still, from 2008 to 2010, 836 were injured and 32 died on Minnesota roads. 

But bicyclists, as it turns out, face another peril: pollution. New research has found that bicycle commuters inhale twice the amount of black carbon particles as pedestrians. Inhalation of such gunk (aka soot) is associated with reduced lung function and even heart attacks. 

The researchers, led by Professor Jonathan Grigg from Barts and the London School of Medicine, compared carbon levels in the lungs of five healthy bicycle commuters those of five healthy pedestrian commuters. The bicyclists had 2.3 times more of the bad stuff in their lungs. Presumably, the cyclists’ heavy breathing — all that good aerobic stuff — is responsible for the increased presence of black carbon.

More bad news

There was even more distressing news from scientists at the University of California in San Diego. The researchers gave smartphones with pollution sensors to 30 study participants and then analyzed data collected over a month. The people doing the most to reduce carbon emissions by cycling or riding the bus “experienced the highest levels of exposure to pollutants,” according to William Griswold, the lead investigator.

How could this possibly happen? Well, it turns out that pollution drifts around, rising and falling during the day, usually on heavily trafficked routes or intersections. So people who bike to work along a very busy route could be inhaling clouds of carbon monoxide and ozone. Being sealed inside a car along the same road would lessen exposure. Bus riders, who are also trying to reduce their carbon footprints, inhale volumes of exhaust by standing at bus shelters.

Fortunately, bikers can vastly minimize their exposure by shifting off a busy route, sometimes only a block away. And, apparently, there are apps that can be downloaded onto a phone that will give cyclists real time pollution information so they can stay away from the worst parts of town. Scientists conducting the study suggest that bus riders avoid standing in a shelter near the back of the bus, which is where air quality is the worst.

There’s probably no quick fix for all those bicycle accidents. Statisticians say that the most common reason for bike crashes is failure to yield right of way. Cyclists often ignore stop signs and lights. For their part, drivers don’t pay attention to bikers. Or don’t even see them — until it’s too late.

Worry not. Two inventors, Jonathan and Andrew Lansey, have developed a bike horn that sounds just like a car. They’ve already raised money to manufacture what they call “Loud Bicycle” on Kickstarter, where you can hear what it sounds like — it should stop any motorist cold — and even place an order.