Which Comes First, Cardio or Weights_ - Alex Hutchinson [8]
Still, when the conditions are unusually hot, many people do manage to push beyond their limits. In 2010, the medical director of the Twin Cities Marathon in Minnesota, William Roberts, published an analysis of eight recent marathons where hot conditions caused “mass casualty incidents” that overwhelmed local health facilities and caused unacceptable delays in emergency care. He found that most of these races started with weather conditions deemed acceptable under the guidelines published by the American College of Sports Medicine. The problem is that the races took place in cities like Boston, Chicago, London, Rotterdam, and Rochester, N.Y.—all northern cities where temperatures are relatively cool for all but a few months each year.
As a result, mass casualty incidents occurred when the “wet bulb globe temperature” (a corrected scale that factors in air temperature, humidity, and solar radiation) was a relatively modest 70°F (21°C) at the start of the race. Crucially, these races all took place in the spring or fall, rather than in the middle of summer when runners would have been used to the heat. In other words, context matters: the actual temperature is less important than how well you’re prepared for it.
Should I avoid exercising outside when air pollution is high?
No surprise, the air pollution in cities is bad for you. And exercise makes it worse, since you breathe in a greater volume of air and bypass the natural filtering of the nasal passages by inhaling through the mouth. That means that when city officials announce a smog alert, there are compelling reasons to think twice about vigorous outdoor exercise anytime between morning and afternoon rush hours, when the levels of most pollutants tend to be highest. But with some careful choices about when and where you go, you can still get in a good—and safe—workout.
DEALING WITH HEAT
Acclimatize: Research shows you significantly improve your heat tolerance after 10 to 14 days of exposure. But it’s not enough to just sit on the porch fanning yourself—you literally have to sweat. A 2009 San Diego State University study had eight volunteers exercise for 10 days, 90 minutes a day after having Botox injected into one arm to block sweating. At the end of the study, the sweat glands in the sweaty arm were producing 18 percent more sweat—a sign of good acclimation—while the glands from the arm that remained dry became less productive.
Breathable clothing: A 2010 study in the journal Applied Ergonomics put the claims of athletic apparel makers to the test, with volunteers exercising for an hour wearing either a cotton T-shirt or a polyester/elastane blend. As expected, the polyester shirt permitted greater sweating efficiency, while the sweat-soaked cotton shirt weighed 50 percent more. Interestingly, though, the cotton shirt didn’t actually make the subjects any hotter—so if you’re committed to your retro gear, you can stick with it. Whatever material you choose, avoid overdressing, or at least use layers that you can strip off as you heat up.
Dunk yourself: If you do find yourself overheating, the quickest way to cool down is to plunge into the pool—and you don’t necessarily need to subject yourself to an ice bath to cool down quickly. Some researchers now argue that pleasant water temperatures of 75 to 79°F (24 to 26°C) are just as effective as colder temperatures and can bring heat stroke victims back to safe temperatures in less than three minutes. The key: the warmer water doesn’t constrict the blood vessels under your skin, allowing more efficient heat transfer.
The basic problem is that sucking in a mix of gases and particles irritates your airways, which can result in coughing fits and difficulty breathing. But doctors now recognize that these symptoms represent just one part of a larger problem. “All the blood in the body courses through the lungs to pick up oxygen,