Cardiovascular Training: Frequently Asked Questions

The traditional belief is that running can damage the tissues in the knee over time due to the high-impact nature of the exercise. Contrary to popular belief though, more evidence is beginning to show that unless you are genetically predisposed to osteoarthritis, an individual of healthy weight with healthy knees should have minimal issues, and casual running may actually strengthen the knees.

What most people don’t realize is that, more often than not, jogging injuries are caused by inappropriate or worn-out shoes rather than by the act of running itself. Some people mistakenly wear shoes that cause their feet to turn inward too much, or over probate, which causes backaches and knee pain, while others choose shoes that do the reverse. So, the next time you go for a jog, and your legs or back start to ache, take a look at your shoes, not your regimen.

The most recent attempt to unravel this mystery comes from researchers at the University of Virginia, who used high-speed cameras and special treadmills with force-measuring surfaces to compare joint motion and impacts. The results, published in the journal Medicine & Science in Sports & Exercise in 2008, show that there are some statistically significant differences, such as knee orientation and peak force. But overall, the researchers concluded that the biomechanics of running on a treadmill are close enough to “overground” running that the differences don’t matter.

This is the same conclusion that many running coaches have reached through first-hand experience. They say that one key advantage of treadmills is that they’re generally softer than sidewalks and roads, and therefore, gentler on the knees.

In any case, the answer is simple: variety. Try not to rely exclusively on the treadmill—and if the weather does keep you indoors for several months, make sure you start with a few easy outdoor runs before jumping into a 10K race.

VO2 max is a term that surfaces whenever feats of great endurance like the Tour de France are in the news. It refers to “maximum oxygen uptake,” the greatest amount of oxygen you’re able to deliver to your muscles when you’re exercising as hard as you can. The more oxygen you can process, the faster you’ll go — which is why many athletes seek out the VO2max testing available at universities and labs for around $100 to $150.

So other than satisfying curiosity, what does testing your VO2 max tell you? Comparing the results of several tests over time does allow you to monitor whether you’re improving or no — but then again, so does entering races. For most athletes, experts recommend lactate threshold testing as a more useful training tool.

You’ve seen the charts on posters at the gym and on the control panels of cardio machines: keep your heart rate in the right zone—warm-up, “fat-burning,” aerobic, and so on—to get the most out of exercise. There’s just one problem: in order to exercise at, say, 75 percent of your maximum heart rate, you need to know what that maximum is. And despite what it may claim, your treadmill really doesn’t know you that well.

The conventional wisdom, used by even the fanciest cardio machines, is that the maximum heart rate is 220 minus your age. It’s simple, easy to calculate, and—more often than not—wrong. It turns out there’s not much scientific evidence for that formula. A better formula is 208 minus 0.7 times your age. But even that provides only a rough average because there’s so much natural variation in heart function. For about one in every three people, the formula will be off by more than 10 beats—enough to put you in a completely different exercise zone. In addition, some recent studies have suggested that aerobic training can lower your maximum by as much as 10 beats per minute as your heart gets stronger.

The only way to reliably determine your personal max, it turns out, is to actually get your heart pumping that fast. That typically requires a cardiac stress test, usually performed in a lab with a treadmill.