Which Comes First, Cardio or Weights_ - Alex Hutchinson [6]
There’s no doubt that, during exercise, your risk of a potentially fatal “cardiac event” is elevated, says Paul Thompson, a cardiologist at Hartford Hospital in Connecticut and a leading researcher on the topic. However, it’s equally well established that any risks you incur during an hour of exercise are dwarfed by the reduced risk of a heart attack—as much as 50 percent lower, according to the American Heart Association—during the other 23 hours of the day.
The problem is that the man-bites-dog nature of rare events, like the death of a young athlete, sticks in the mind. “These events really do have a chilling effect on people’s desire to exercise,” says University of Toronto epidemiologist Donald Redelmeier. To put the risks into context, Redelmeier and a colleague analyzed marathon results from more than three million runners. They found that about two deaths occur for every one million hours of aerobic exercise—a rate that isn’t significantly different from the baseline hourly risk of being alive for the average 45-year-old man. The study, published in the British Medical Journal in 2007, also found that when cities close roads for a marathon, the chance that a traffic death will be averted is nearly twice as high as the chance that one of the runners will die.
Of course, statistical arguments aren’t much help if it’s your life on the line, so it’s natural to look for ways of screening out the risk. Indeed, autopsies after such deaths reveal pre-existing heart abnormalities in about 94 percent of cases, Thompson says. But it doesn’t necessarily follow that we can screen for these abnormalities, because they’re so common in the general population. About 10 percent of healthy athletes display abnormal electrocardiograms—and upon further examination, “you keep finding more little abnormalities,” Thompson says, producing an impractically high rate of false positives.
Redelmeier agrees: his analysis indicates that any screening program would need to be exceptionally accurate and inexpensive to be worthwhile. Otherwise the resources would be better spent elsewhere, such as improving paramedic staffing at events like marathons to respond to the all-but-unavoidable cardiac events that will sometimes occur. In Kassap’s case, the cause turns out to have been myocarditis—an inflammation of the heart caused by a virus, which no screening could have predicted. “People want a riskless society,” Thompson says. “So I tell them to go to bed alone.”
Will exercising in cold air freeze my lungs?
The strangest story that Michel Ducharme, a scientist with Defence Research and Development Canada, has encountered is the cross-country skiers who were swallowing Vaseline to coat their airways as a protective measure against cold air. “That’s just crazy,” he says—and it’s entirely unnecessary. Ducharme is the researcher whose work led to a major revision of the wind-chill scale in 2003, thanks to the efforts of impressively dedicated volunteers who sat in a frigid wind tunnel until their faces developed the first stages of frostbite. And he firmly dismisses the idea that your lungs will suffer from contact with cold air. “The heat exchange is very quick,” he says, “and there’s no evidence of any risk of freezing tissue.”
DO YOU NEED TO SEE A DOCTOR BEFORE EXERCISING?
The Physical Activity Readiness Questionnaire (PAR-Q) was originally developed by the British Columbia Ministry of Health and is now widely used around the world. If you answer yes to any of the seven questions, you should see a doctor before heading to the gym.
• Has your doctor ever said that you have a heart condition and that you should only do physical activity recommended by a doctor?