laiflonglearner’s Reviews > Breath: The New Science of a Lost Art > Status Update

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 invigorated and strong after a workout, you'd feel tired, shaky, and nauseated

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.

This process explains why the first few minutes of an intense workout are often so miserable. 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.

Anaerobic energy is generated only with glucose (a simple sugar), and it's quicker for our bodies to access. It's kind of a backup system and turbo boost when the body doesn't have enough oxygen. But anaerobic energy is inefficient and can be toxic, creating an excess of lactic acid. The nausea, muscle weakness, and sweating after you've pushed it too hard at the gym is the feeling of anaerobic overload.

No matter what we eat, how much we exercise, how resilient our genes are, how skinny or young or wise we are—none of it will matter unless we're breathing correctly