While out riding i occasionally get what i think of as a magical breath. it is deeper than normal and almost euphoric. i can never reach down that deep deliberately, it just sometimes comes when i am not expecting it. normally happens when i am riding hard either during a long ascent or pushing it hard on a flat. wondering if i am the only one that get this from time to time.

Breath control is an entire discipline of its own, often neglected by most amateur and even some pro athletes. Some trainers don't pay much attention to it, if at all.

Each sport has unique requirements for optimal breath control. The same diaphragm breathing technique that works well for high intensity endurance sports won't work for martial arts where a blow to the body can be incapacitating. Most boxers and martial artists endure heavy blows to the torso in training from "medicine" balls and even punches with sparring gloves to toughen up the abdominal and intercostal muscles. That technique works well for the usual 2-5 minute rounds with full minute breaks. But it's not necessarily useful for cyclists or runners.

After being hit by cars twice (2001 and 2018) I've had some long recovery periods regaining breath control. Even after my shoulder recovered pretty well from the 2018 incident, I'm still having difficulty with stiff and painful intercostal muscles. On most longer rides this year -- 50-60 miles -- after around 30 miles I was panting for breath. It wasn't the usual allergies, asthma or even my recent bout with a respiratory virus. The torso muscles were tightening up, cramping and preventing getting full, easy breaths. And during any intensive effort it doesn't help much to concentrate on breathing deeply. That mindfulness stuff doesn't work that way. We have to practice breath control before the event.

So I cut back on the group rides, which force us to ride at a pace set by someone else, and focused on solo training of 20-40 miles, paying attention to when my torso would tighten up and hinder good breathing. And I'd work on that at home, with core exercises, etc. And I still use the incentive spirometer I got at the hospital after my surgery last year.

Occasionally, after a good warmup, including stretching and using a percussion massager, I'll feel like my lungs are suddenly opening up. But it's just hitting the sweet spot of diaphragm and intercostals finally loosening up that day and enabling full breaths without panting and gasping. It finally peaked this week and I was able to set my fastest times on a 30 mile route I've ridden hundreds of times, improving 1-2 mph overall in neutral wind (3 mph or less, no particular direction). My previous best times were often wind assisted, and all occurred before the injury last year. Often either my legs or lungs will tire before the other, but this week the body and respiration have been pretty much in sync. Took a lot of work and physical therapy to get there.

Google around and you'll find some good tutorials and videos on breath control for athletes. Very helpful stuff.

What you're experiencing could be a massive surge of endorphins...aka "runner's high". I used to get it fairly often while swimming in my 20s. Somewhere around the 20 minute mark a warm, relaxing feeling would wash over my body and I felt as if my muscles "relaxed" yielding deeper, stronger strokes.

I've been biking almost daily since 1992, but I had never felt this over-whelming warm rush of "well-being" while biking, until a year or two ago. It happened twice within a month, but alas, hasn't returned no matter how hard I push, how far I ride, or how long I stay in the saddle.

I still feel some elevation of "spirit" after a few minutes on the bike, and the small aches and pains that announce the approach of 60 years of life get muted for an hour or two after a ride (except my hands...dammit). And I do find myself "in the zone" fairly often...but that warm rush of overpowering euphoria and well-being with the associated relaxing and "deepening" of muscle strokes and breath....that has remained elusive to me.

I know there is a physiological explanation for all this...but I agree with your nomenclature...

...it IS magic!

It sounds a lot like the "runner's high." Which I remember a comedian saying, "I'm a smoker, so I don't need to jog 10 miles to get a runner's high. All I need to do is climb a flight of stairs."

distinctly remember a single occasion where that happened to me while running one night approx 40 yrs ago. I was so surprised by it, that I mentioned it to my parents