Breath: The New Science of a Lost Art

Sleeping with an open mouth exacerbates these problems. Whenever we put our heads on a pillow, gravity pulls the soft tissues in the throat and tongue down, closing off the airway even more. After a while, our airways get conditioned to this position; snoring and sleep apnea become the new normal.

When seasonal allergies hit, incidences of sleep apnea and breathing difficulties shoot up. The nose gets stuffed, we start mouthbreathing, and the airways collapse. “It’s simple physics,” McKeown told me.

Finding the best heart rate for exercise is easy: subtract your age from 180. The result is the maximum your body can withstand to stay in the aerobic state. Long bouts of training and exercise can happen below this rate but never above it, otherwise the body will risk going too deep into the anaerobic zone for too long. Instead of feeling invigora

When we run our cells aerobically with oxygen, we gain some 16 times more energy efficiency over anaerobic. The key for exercise, and for the rest of life, is to stay in that energy-efficient, clean-burning, oxygen-eating aerobic zone for the vast majority of time during exercise and at all times during rest.

Remember those cells that evolved to eat oxygen 2.5 billion years ago and kicked off an explosion of life? We’ve got some 37 trillion of them in our bodies.

These two energies are made in different muscle fibers throughout the body. Because anaerobic respiration is intended as a backup system, our bodies are built with fewer anaerobic muscle fibers. If we rely on these less-developed muscles too often, they eventually break down.

Our lungs and respiratory system haven’t caught up to supply the oxygen our bodies need, and so the body has to use anaerobic respiration. This also explains why, after we’re warmed up, exercise feels easier. The body has switched from anaerobic to aerobic respiration.

But anaerobic energy is inefficient and can be toxic, creating an excess of lactic acid. The nausea, muscle weakness, and sweating you experience after you’ve pushed it too hard at the gym is the feeling of anaerobic overload. This process explains why the first few minutes of an intense workout are often so miserable.

Anaerobic energy is generated only with glucose (a simple sugar), and it’s quicker and easier for our bodies to access. It’s a kind of backup system and turbo boost when the body doesn’t have enough oxygen.