How do I determine my maximum heart rate and how to breathe
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 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,” says Hirofumi Tanaka, head of the University of Texas’s Cardiovascular Aging Research Laboratory.
In fact, it started as a simple rule of thumb based on a few studies in the early 1970s that included smokers and patients on heart disease medication, and almost no subjects over the age of 55. A better formula, Tanaka has found, 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. You can also get a decent estimate by wearing a heart rate monitor for a 15- to 20-minute run in which you gradually accelerate from a jog to an all-out sprint for the last few minutes.
Ideally, finish with a couple of laps on a local track, advises veteran Atlanta-based running coach Roy Benson: “After every hundred meters, look at your heart rate and accelerate as hard as you can,” he says. “You’re looking for your heart rate to peg at an upper limit.” You could do this at a local 5K race, where the crowds and competition will help motivate you to reach your true maximum—but the key is beginning gradually, so that your legs don’t fail before your heart maxes out.
Knowing your true max allows you to get a more realistic sense of what training zone you’re in. Still, there are other pitfalls you need to watch out for. In hot and humid conditions, sweating can reduce your blood volume and cause “cardiac drift”: your heart will beat faster even though your effort stays low. In cool and dry conditions, the opposite can occur, keeping your heart rate artificially low even when you’re going at the desired pace. That means that, while the heart rate monitor is a useful tool, the final judge of training effort should always be how you feel.
What’s the best way to breathe during exercise?
Birds do it, and so do horses. So it seems natural to expect that humans would synchronize their breathing with rhythmic activities like running, cycling, or rowing. Sure enough, decades of studies have found links between stride rate and breathing rate for both novices and experts, at slow and fast speeds, in many different activities. Some studies suggest this unconscious synchronization makes your movement more efficient—but the latest research suggests that trying to force yourself to breathe in a certain pattern can backfire.
Horses maintain a fixed one-to-one ratio between strides and breaths because their lungs and breathing muscles are shaken rhythmically by the impact of their hooves on the ground. Flapping wings put birds under similar constraints. Humans, on the other hand, walk upright, so the jarring impact of each foot-strike doesn’t directly interfere with breathing muscles.
Still, a series of studies in the 1970s showed that if you put subjects on a treadmill or exercise bike, some (but not all) naturally fall into a pattern where their breathing rate is synchronized with their cadence.
The ratio of full strides (i.e., counting each time the right foot hits the ground) to full breathing cycles (i.e., counting each exhale) varies widely among subjects, with common observations of 1:1, 2:1, 3:1, 3:2, 4:1, and even 5:2. The most common among runners is two stride cycles for each breath.
A Swiss study in 1993 found that runners seem to burn slightly less energy when their breathing is coordinated with their stride rate—a finding that spurred some coaches to encourage their runners to focus more on their breathing. Numerous studies since then have explored whether synchronized breathing makes movement feel easier or burns less energy, with conflicting results.
After several decades of research, the failure to demonstrate any clear link between synchronized breathing and efficiency suggests that if there is any effect, it’s too small to be of practical significance. Still, the idea that there’s a “correct” breathing pattern has persisted ever since.
More recent research has suggested that trying to consciously control your breathing is quite different from letting your breathing adopt a rhythm subconsciously, and it may even have negative effects. A 2009 study from the Institute of Sports Science in Münster, Germany, had runners focus their attention on either their surroundings or their breathing. When they focused on their breathing, the subjects took deeper breaths and slowed their breathing rate from 37 breaths a minute to just 30.
The result: they burned almost 10 percent more energy compared to when they simply let their mind wander. The researchers conclude that we’re pretty good at picking the right breathing rate without thinking about it, so we just make things worse when we try to interfere.
Still, there are some useful breathing tips that new exercisers should know. For instance, it’s easier to get lots of oxygen in by breathing through your mouth and nose rather than either one on its own. And synchronizing your breathing is important if you’re lifting weights: exhale as you lift and inhale as you release, making sure not to hold your breath.
But in general, if you find yourself panting uncontrollably as you start a new cardio activity, it’s far more likely because you’re starting too fast than because you’re breathing wrong. Slow down, enjoy the scenery around you, and let the breathing take care of itself.