James Nestor is a journalist who has written for Outside magazine, Men’s Journal, Scientific American, Dwell magazine, National Public Radio, The New York Times, The Atlantic, the San Francisco Chronicle magazine, and others.
I will preface this with what James states himself on the topic of what should an asthmatic do in hearing this information -
"I'm not a breathing therapist. I'm not a doctor. And one should continue going to his doctor and taking their bronchodilators. So I'm a journalist who went into this field with zero slant, with zero objective. Then I would tell one after that disclaimer that I would seek a therapist who has experience dealing with asthma attacks and using breathing to help them there."
Breathing is essential to recovery, endurance, and performance
“If you’re not breathing right, you’re never really going to be healthy” – James Nestor
Breathing allows levers into systems we can’t otherwise control
Breathing needs to move from something mystical to everyday practice
Nasal breathing is the most efficient and beneficial way of breathing with beneficial effects for asthma, anxiety, blood pressure, and much more
For breath work newbies: Start with a 6-second inhale and a 6-second exhale
Noticeable benefits of breathing depending on the level of fitness – athletes who use nose breathing regularly will need more intensive practice than someone with chronic asthma who will notice improvements almost immediately
James claims studies have shown that teaching asthmatics to take control of breathing can reduce the number of asthma attacks within one month
Recommended breathing techniques for asthmatics (under therapist supervision): Papworth, Buteyko - these are actually mentioned in the mayo clinic article here.