Proper breathing while exercising is essential for a successful workout, according to personal trainers.

THE PROVIDENCE JOURNAL / BOB THAYER

My favorite thing about yoga classes — other than the part at the end when you get to lie down and act like a corpse — is that the instructors always remind me to breathe. Pretty much without fail, whenever I get the cue “Don’t hold your breath,” I am. And as soon as I go for a deep, belly-expanding inhale, I feel amazingly able and at ease.

It’s no mystery why this happens. Stress causes us to tense up, while breathing brings oxygen to the muscles and allows us to relax. “It helps with concentration. It increases endurance. It slows your heart rate,” rattles off Alvaro Maldonado, co-owner of a personal training gym. In short, full lungs do a heck of a lot more than just keep you alive, especially during strenuous physical activity.

Any personal trainer worth his spandex knows the basic rules: You want to exhale on the exertion part of a movement, and inhale on the recovery. During cardiovascular exercise, short, shallow breaths are a clue that you’re overdoing it. And if you can develop a pattern for your breathing, you’re likely to last longer.

But much of the time in gym settings, the breath takes a back seat to other concerns: what we’re lifting, how we’re squatting, when we’re leaving. That may be why when Karen Sherman, a senior investigator at Seattle’s Group Health Center for Health Studies, looked into treatments for chronic low-back pain in 2005, weekly yoga classes plus home practice appeared to be slightly more effective than weekly sessions of aerobic, strengthening and stretching exercises plus home practice.

“What’s the active ingredient?” asks Sherman, whose results were published in the Annals of Internal Medicine. No one knows why yoga was more effective than the other exercises, but Sherman believes part of the answer is attention to breathing.

“It’s not that people don’t think about breathing, but they don’t give you the same language and imagery that creates more awareness,” she says. “For someone with back pain, one of the possibilities is they haven’t been paying attention to their bodies.” If you’re doing more-vigilant surveillance, there’s a better chance you’ll notice that you should stand straighter or move differently, and those tweaks could provide the treatment you really need.

When it comes to how to breathe, Deborah Norris, an American University psychologist-in-residence and a specialist in behavioral medicine, is fairly nonpartisan. There are countless forms of breath control in yoga that have specific instructions about when to inhale, exhale and hold, and Pilates emphasizes a style of breathing that focuses on expanding the rib cage while keeping the abs fully engaged.

“My approach is to tune in to how the body chooses to breathe, watching the breath, allowing it to happen and observing every dimension,” Norris says. “It’s cool as it passes through the nostrils or mouth, warm as it enters the lungs. Is there movement in the chest or belly? Do your shoulders or back move? Do you feel it in your arms and legs?” No matter what your answers, you’re likely getting the desired effect, which is a greater sense of self and a feeling of control.

Maldonado taps into a similar approach with his weekly stretching and alignment class, which draws from Pilates, yoga and multiple dance techniques to enhance flexibility, coordination and performance. “The bottom line is, there isn’t a specific way to breathe. We all have different rhythms, and we all have to find a way to send oxygen to the muscles,” he says.

Once you figure out how best to get air flowing in and out of your body, then you can attempt to master the sorts of moves he teaches. The bends, extends and reaches all rely on the power of the exhale to stretch your limbs further. And if your tummy is bloated with air when you need to lean over, you’ll block your own progress.

There’s also no cheating when it comes to breathing. “I can hear if they’re relaxed and focused and the body is doing what it’s supposed to be doing,” Maldonado says. When they’re not, his trick — other than reminding them to inhale and exhale every few seconds — is to tell them not to stiffen their faces. “If they’re like this,” he says, demonstrating a pained, tight expression, “they’re not relaxed.”

Exercise can often seem like the opposite of relaxation. Our goal is to exhaust our muscles, shoot our heart rates up and overcome the competition (whether that be a person or a personal best). But performance actually improves when you figure out how to keep calm while exerting yourself.

“Breathing badly is something that’s going to make you fatigued faster and hurts form, and that’s what gets you injured,” says Emory Land, a triathlon coach. “You’ll never reach your potential.”

So, let this be a reminder to you — and me: Don’t hold your breath.