The answer is yes. When it comes to breathing, sometimes less is more. 

I was recommended James Nestor's 2020 book "Breath: The New Science of a Lost Art" by a colleague because of its deep insights into aspects of the Alexander approach to breathwork and I found many of this book's ideas surprising.  It is a highly recommended and refreshingly brisk read (though some of the extreme practices he labels as "breath plus" I wouldn't endorse), especially if you get the audiobook version which includes about a half hour of guided breathing exercises at the end. 

Here are some of the key insights from the book, with some commentary on how it connects to Alexander Technique work, along with some surprises I encountered. 

Should you try to breathe through the nose or the mouth? The Alexander Technique viewpoint is typically that breathing through the nose is more efficient. F.M. Alexander even claimed that doing so "cleaned" the air. Nestor confirms just that. Through exhaustive (literally) and extreme experimentation and research, he finds that chronic mouth breathing is connected to a number of ill effects including fatigue, sleep apnea and other sleep disorders, and cardiovascular troubles.  By contrast, nose breathing is connected to a number of benefits including improved energy, rest, and even athletic performance.  This only applies to chronic breathing--taking a few breaths through your mouth every once and a while isn't going to have any ill effect. It is about how you breathe in general.

One of the figures Nestor investigated in the book was breathing specialist Carl Stough, whose work is about jump-starting the the primary musculature of breath--the diaphragm. In order to do so, he created a series of exercises that involve, among other things, an emphasis on extending the exhale. The basic idea is that in order to take a deep breath, you have to fully give up your last one. The results of his exercises were reportedly dramatic: cured emphysema, the restoration of vitality to bedridden people. The Alexander Technique emphasizes the exhale in exercises such as the "Whispered Ah" and the "Silent lalala", and many Alexander Technique teachers (myself included) have incorporated some of Stough's ideas into our basic practices. You can see some of this emphasis in my video "Two Breathing Exercises" I released on YouTube:

Nestor finds that most of us breathe too quickly--we take many more breaths a minute than we need to, and this has a strong impact not only on our lungs but on the regulation of our nervous system. By consciously slowing our breath to a relaxed, even flow we have the possibility of downregulating our anxiety as well as helping our whole system function with more ease. There is even a theoretical optimum breath--five and a half seconds in, five and a half seconds out. 

Even though this is very much in line with A.T. thinking, I still found aspects of this idea surprising. I work with many of my performance clients to get fuller, larger breathing to support their voices. If you are singing a high "c", a voluminous breath is useful. It turns out that if you are just sitting on the couch, not so much. The reason why is fascinating--too much oxygen isn't great for your system, and carbon dioxide can be. To encapsulate the argument, the easiest thing to do might be to make a metaphor: when you take vitamins, your body can only absorb so much at once. So taking 10000 percent of your daily value of vitamin c isn't super useful. Furthermore, many vitamins have to be taken with other nutrients, such as fats, to be absorbed at all. Think of oxygen like it is the vitamin, and carbon dioxide like it is the fat--carbon dioxide acts as a conveyor for the oxygen that helps  your body absorb it. Overly voluminous breaths keep carbon dioxide from being produced, and as a result you cant absorb the oxygen you take in--as counterintuitive as it may seem, you starve yourself of oxygen by taking in too much air. In addition, huge breaths can put your nervous system into "emergency mode" and cause anxiety and other side effects. The solution is to breathe deeply, but in measure--two things that may seem to be at odds, but aren't. The key is having ease of breath and not tensing to pull it in. This works fabulously with each of the last two points--by breathing slowly and emphasizing the exhale, you are unlikely to overbreathe.

Perhaps the most surprising thing Nestor espoused to me is that both holding your breath and intentional overbreathing, two things that are not good for you when done chronically, can be therapeutic in short bursts. They can help to train your regulatory and nervous system and have a particularly profound effect on anxiety.  He lays out examples of exercises that are best done with a lot of specificity and in a safe place--therefore, I won't attempt to describe them in detail here, but I recommend checking them out. I have tried several since finishing the book and find the breath holding exercises particularly effective. Who knew?