Breathing is simple, right? We do it all day long without thinking about it—at least, until a flight of stairs makes its way into the picture or sprints are the workout of the day. You’ll be fine if you never give a second thought to the breaths you take throughout the day, but you’ll be far better if you do.

Just ask Peter Lee Thomas, lifelong martial artist and trainer to A-list celebrities like Halle Berry. He looks like a bodybuilder, could make easy work of kicking your ass (but wouldn’t), and counts practicing breath training techniques as one of the foundations of his daily routine.

Going out of your way to consciously breathe may sound far out, but some of the world’s fiercest athletes can vouch for it. Bruce Lee may be the most well-known, but even if you’re no martial artist and think that this is no activity for a gym rat to use in their routine, consider the fact that legendary six-time Mr. Olympia Dorian Yates is also into it.

The concept of diaphragmatic breathing—the much less far-out-sounding way to say taking control of your breaths—is nothing new. It’s a practice that dates back as early as the first millennium, B.C., and even modern psychological studies have found that it can be an effective, non-pharmacological way to reduce anxiety, depression, and stress.

Those psychological benefits are what keeps Thomas hooked, and they’re important now more than ever in light of the coronavirus pandemic, which has countless people understandably stressed and frustrated.

“This is where the breathing taps in,” he says. “This is where collective calmness, that warrior mindset where you have to be fully relaxed in the most unrelaxed environments, comes in. This is what gets me through my day, is truly tapping back into the breath.”

We picked Thomas’ brain to find out how he uses breathing techniques, what they’re all about, and his tips for beginners to start their own breath training journeys.