Breathing is simple, right? We all do it, a dozen times a minute, at least. Even a newborn baby can do it.

But that most basic of human processes can be improved upon, so we get more out of it.

“Breathing well, in my view, is using your lungs to their best capacity to bring in oxygen most efficiently,” said Dr. Sumita Khatri, a pulmonary physician and co-director of the Asthma Center at Cleveland Clinic in Ohio.

There is no singular “best” way to breathe.

“When you need more [oxygen] you do more deep breathing rather than shallow,” she said. “It’s also a matter of you getting rid of carbon dioxide. Oxygen comes in to create energy, and you’re creating waste carbon dioxide. Breathing deeply allows that carbon dioxide to be eliminated. You don’t have to breathe deeply all the time. [But] it’s more efficient slow and deep than fast and shallow.”

Dr. Ingrid Yang, a Chicago physician who is also a yoga instructor and author, said that how we breathe is activity-dependent. Running or gymnastics requires one type of breathing, yoga another. Still, she said, breathing is always there, “and that is the magic of it. Even when we are sitting in front of our computers at work, or waiting for the doctor to call, or on a first date, it is always there for us to come back to and focus upon, so it brings us into our bodies, our moments, and invites a sense of well-being if we will allow it in.”

Here is advice from the experts on optimal breathing:

The mechanics: The American Lung Association explains the process thusly: Air enters the body through the nose or mouth. The throat, or pharynx, passes the air to the trachea, which branches into two passageways that lead to the lungs. Below the lungs is a wall of muscles, the diaphragm. By moving downward, it allows air to enter the lungs; when it moves upward, air is expelled.

Getting the most: Khatri said that we use only 75 percent of our capacity. “One of the things we don’t realize is our lungs have a great deal of reserve. We may get short of breath [when we exercise], but our lungs are not limiting our capacity.”

If a person keeps everything else healthy — eats right, maintains a good weight, exercises, pays attention to environment — the lungs can step up and do even more, she said. Things such as aerobic exercise and swimming seem to help with exercise capacity.

She also points to the discipline of yoga, in which breath control is emphasized along with the body movements. “You learn strengthening of the shoulder and chest muscles,” Khatri said, “which also affects breathing.”

Be aware, feel the flow: The first step to better breathing is to become aware of your breath: Realize how your diaphragm is performing as you inhale and exhale, Yang said. You’ll become used to the idea that when the diaphragm contracts and the lungs fill, the abdomen expands, as well. Depending on your posture, you also may feel the expansion of your rib cage along the sides and even along the back.

“In the process of training your body to breathe, you are simply learning to recognize the signs of good breathing and feel the flow of the breath in an unbroken, relaxed stream,” she explained.

Yoga: In basic yoga breathing, there are four stages, according to Yang.

The first is inhalation, or puraka, when you draw in air smoothly and continuously in a single inhalation through the nose. The second is a pause after inhaling, or abhyantara kumbhaka. During that stage, the air is being retained in the lungs without any movement.

“Beginners may try hard as to not breathe during the pause, motionless,” Yang said. “This gets easier and more automatic eventually, though.”

The third stage is exhalation, or rechaka, which also should be smooth and continuous and through the mouth. Yang said this is easier than inhalation because the first stage requires some muscle energy; this stage relaxes tensed muscles. The fourth stage is the pause after exhaling, also known as the empty pause or bahya kumbhaka, when the person pauses before inhaling again. The empty pause is the end of the cycle, and inhaling again begins a new one.

Compromised breathing? Khatri said that people with physical limitations — asthma, emphysema, COPD (chronic obstructive pulmonary disease) or lung cancer, for example — can improve their breathing and quality of life through a pulmonary rehab program.

These programs consist of muscle strengthening of the upper and lower body. There are supervised treadmill-based exercises, and patients are closely monitored and coached and get oxygen if needed. The routines typically last three months. She says that fitness and wellness centers are places to find and investigate such programs.

Types of breath control: “In yoga, we practice pranayama breath [conscious control of the breath],” Yang said. “This is when we use a deep diaphragmatic breath along with a constriction of the pharynx so the length of the breath is elongated. This gives us time to consider our breath, very precisely and consciously, to bring us further and deeper into the present moment. On the other hand, in meditation, or at least the type that I teach and practice, we practice an ‘easy’ breath: one on which we are not necessarily trying to control it — we are simply observing it.”

Don’t force it: As people pay more attention to their breath, the length of each breath gets longer as they exercise the muscles — especially the diaphragm — that help them breathe. Use it, work it, and the diaphragm will strengthen and allow for deeper breathing.