turned on, the anaerobic system becomes active to supply the energy
needs. It’s not unlike an overtrained athlete who builds the anaerobic
system with too much hard work and too little aerobic exercise. In
both instances the same type of imbalance occurs — too little aerobic
and too much anaerobic activity.
Excess anaerobic activity, through some combination of over- or
under-exercise, work stress or diet, inhibits the aerobic system
through several mechanisms:
- Increased anaerobic function can change your muscle
fibers, resulting in more anaerobic fibers and fewer aero-
bic ones. - Increased anaerobic function produces more lactic acid
which can inhibit the enzymes necessary for the aerobic
fibers to function properly. - Eating too much carbohydrate, especially refined sugar,
increases the sugar-burning anaerobic system while
decreasing fat-burning. - Too much anaerobic function can be a significant stress,
and, like any stress, can increase stress hormones to dan-
gerous levels.
It’s possible to improve both aerobic and anaerobic function, with
the result of high levels of both. But the first step must be improving
your aerobic system. Since the human body is made up of mostly aer-
obic muscle fibers, most of your physical activity should be aerobic.
There is also a lifestyle factor to consider: For many people, from the
time they get up in the morning until they finally drop back into bed
at night, they are rushing, hurrying and continuously under stress.
We need to learn to better pace our lives for the 1,000-mile journey.
Aerobic exercise, along with good nutrition, can correct common
anaerobic system excesses, allowing you to build better health.
Case History
Gary, a high-level executive in a stressful job, started exercising
at his company’s gym. At first he felt great. He lifted weights
three or four times a week, jogged on the treadmill and played192 • IN FITNESS AND IN HEALTH