MEN'S MODE

dying BREATHS

By Rohitha Perera

Every day, millions of men and women run and cycle to improve their health and fitness. So why are some of them speeding toward an early grave?

Five times a week for the past 5 years, I have been unwittingly but systematically poisoning myself.

Every morning, I run for 1 hour along Duplication Road. But there's a catch to my moderate, seemingly harmless routine: until recently, the screech of city buses and the reek of diesel trucks always felt like a small price to pay for the pleasures waiting on the trail.

Here's what I didn't know: With every deep draught of oxygen, I also gulp down alarming quantities of ozone, carbon monoxide, microscopic particulate matter, sulfur dioxide, nitrogen dioxide, lead, and a witch's brew of other pollutants. By conducting part of my workout at midday along a congested street, I am reducing my lung function, constricting my air passages, courting chest pain, increasing my chances of developing asthma, unleashing free radicals to catalyze carcinogens in my bloodstream, and activating cellular processes that might lead to a heart attack.

When I now see people running or bicycling along a busy street in the middle of the day, I want to tackle them and scream at them to stop, at some intersections, we ought to post 'No Exercise Allowed' signs.

INHALING THE OZONE

It may be hard to imagine that vigorous outdoor exercise -- generally trumpeted as an all-purpose antidote to disease and a retardant to mortality -- could actually help bad air hurt you. But the explanation is simple: When you're running, cycling, playing cricket, or shooting hoops, you breathe in more of it. A lot more.

A sedentary person inhales approximately 15,000 liters of air per day, or 6 to 10 liters per minute. During heavy aerobic exercise, however, you draw in 60 to 150 liters per minute, delivering oxygen throughout 600 to 900 square feet of surface area in the lungs.

That means the exerciser breathes in 10 to 15 times more pollution than the sedentary person, and he's sucking it deeper into his lungs. In fact, just by stepping out of the door, you could be exposed to five times the ozone you'd inhale if you stayed inside. So if you're outdoors and exercising Well, do the math.

The numbers grow more harrowing, because you breathe primarily through your mouth during exercise. At the same time that I'm pulling vast clouds of bad air deep into my lungs during my noon run, I'm also bypassing my body's remarkably effective air-filtering system: the nasal passages. (Mucus traps particulates, and then tiny, waving, hair like structures called cilia push the old mucus up and out of the body.) The triple whammy of breathing fast, deeply, and through the mouth makes my daily run -- and perhaps your regular workout -- an ozone/particulate/carbon monoxide orgy.

Eventually, our bodies defend themselves against air pollution by breathing less. Air passages tighten, and breathing becomes labored. Our exercising bodies are ensnared in an intractable dilemma: While working furiously to progress more air to feed oxygen-hungry muscles, they simultaneously strive to protect us from that air. Our pulmonary and cardiovascular systems strain like air conditioners in an extended heat wave and eventually, inevitably, break down. Early symptoms often include wheezing, coughing, scratchy throat, headache, chest pains, and watery eyes. Other, long-term effects are considerably more dire.

GASPING FOR POLLUTED AIR

In Scotland, for instance, researchers studied 30 healthy men cycling on exercise bikes while exposed to diluted diesel exhaust. After 1 hour's exposure to the fumes, the cyclists developed constricted blood vessels and showed a reduction in tPA, and enzyme that breaks down blood clots in the heart. In another study, 17 competitive cyclists were exposed to varying levels of ozone while exercising; their endurance decreased by approximately 30 percent, and their lung function by 22 percent.

Research conducted in Finland shows an even clearer connection between dirty air and heart-attack risk. Every 2 weeks over a 6-month period, scientists monitored 45 volunteers as they exercised in simulated dirty-air conditions. Results linked both fine-particle pollution (the effluvia issuing out of smokestacks) and ultra fine-particle pollution (the invisible emissions from motor vehicles) with a threefold increase in the risk of ischemia, a potentially lethal shortage of oxygen reaching the heart muscle.

Perhaps most disturbing is how airborne toxins can harm us without triggering symptoms. In Southern California, for instance, researchers examined 107 fatal-accident victims, ranging in age from 14 to 25. Before their deaths, none reported breathing problems. Yet autopsies revealed that 86 of the deceased -- 80 percent -- had chronic lung disease. The message to cardio devotees: Easy breathing can confer a false sense of security.

Healthy, active people tend to underestimate the harmful effects of polluted air, because they don't wheeze or experience chest pain. Feeling invulnerable, they continue to exercise, putting themselves at a greater risk.

THE BIG SIX CAUSE AN ASTHMA SPIKE
I wanted to know the kind and quantity of pollutants I was inhaling, and thereby gain a rough sense of what my lungs might look like after years of unintentional abuse. The research I conducted led me to this conclusion: the study of pollutants other than the Big Six (ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, particulate matter, and lead) and analysis of air-pollution microclimates -- i.e., localized areas in which the air is significantly dirtier than in regions as a whole. Among the former, diesel particulates -- the black waste issuing primarily from trucks, buses, locomotives, and other large conveyances -- are emerging as particularly worrisome.
NO MORE SMOG JOGS

Despite the darkening diesel cloud, spiking asthma rates, and proliferation of scary studies, all the documentation that I have researched assures me that, on balance, I've been doing myself more good than harm with my daily run.

Exercising early in the day, when diesel particulates, ozone, and other air pollutants are at their lowest levels, or after nightfall, when traffic abates. Ozone forms when sunlight reacts with automobile and industrial emissions, so it accumulates to significant levels by about 11 a.m. and peaks at around 3 p.m. (After sunset, ozone can no longer form, so the concentration decreases.) By the same token, ozone levels are significantly higher during the sunnier months.

Other commonsense mitigating tactics include standing in front of the line of traffic at stoplights and busy intersections, and skipping your outdoor workout if the AQI [Air Quality Index] exceeds 70. Consuming fruits and vegetables high in vitamin C, such as peaches and red peppers, stimulates production of glutathione, a liver enzyme that helps prevent free-radical damage in the lungs. And just a few places down the antioxidant alphabet is vitamin E, which can also help repel radicals.

The most effective and logical response to air pollution, of course, is to drive less, consume less, and thereby reduce what you are, directly and indirectly, pumping into you city's atmosphere. No one is greener in this regard than bicycle commuters -- and no one, ironically, breathes more traffic exhaust.

Ironically, when you're talking about air pollution and exercise, it's often what you can't see that gets you.

The most effective and logical response to air pollution, of course, is to drive less, consume less, and thereby reduce what you are, directly and indirectly, pumping into your city's atmosphere.
