The thing to understand about conventional aerobics is that on the days you’re doing your aerobics, you’re benefiting, but on the days you’re resting, not much is being accomplished. This is why so many overload the frequency of their aerobic workouts. Personally, I believe no more than five aerobic workouts should be conducted each week, any more is excessive. Each workout itself might fluctuate between 30 - 60 minutes with occasional 90 - 120 minute sessions; like afternoon walks or bike rides. Overtraining sets in when one tries to rely on aerobics for total body conditioning reaching up to 7 workout days each week with excessively long sessions. At first, overloading the body with this volume of training might seem to be manageable, but if the body is not completely recovered before commencing your next workout, your recuperative needs will compound themselves over time and your results will stagnate and might even regress. This is when you know you’re overtraining.

On the other hand, if you try my suggestion of interval aerobics, on the days you’re exercising, you’re benefiting and, on the days you’re resting, you’re still receiving results! Interval aerobics will condition the heart and lungs while, at the same time, create the muscular trauma needed to ignite post workout metabolism building the lean tissue you need. Isn’t that amazing? It’s like making a great investment and enjoying the interest. Plus, you don’t have to exercise as often or as long.

Interval aerobics can be applied to walking, biking, running, stair climbing, rowing, and all other forms of this activity--the list is as long as the number of activities you can select from. You can also try alternating up hills then back to flat land while walking, biking, or running. Some of the new aerobic machines even have preset computer interval courses which make interval aerobics easy to apply.

Getting Back to the "Why's" of Aerobics
Aerobic exercise produces benefits you simply cannot live without. Getting a regular dose of aerobic exercise contributes to vibrant health and can extend mean life span. Specifically it benefits:

The Brain
As with any activity, voluntary or involuntary, the brain is the master controller of the human body. Those who are sedentary don’t spend enough time thinking about, or doing things for, their bodies. They also don’t engage in physically challenging activities which require specialized skills to perform.

On the other hand, those who engage in exercise regularly are like pilots in the cockpit behind the controls of a sophisticated machine. Exercise requires billions of psychophysiological actions that only the brain can pilot. As we condition ourselves, we have the ability to communicate with the various systems of our bodies and, in many ways, control the destiny of our health. Once a satisfactory level of conditioning is achieved, the body, and its various systems, begin to operate in efficient harmony, largely due to improved brain function.

The Heart
Conditioning the heart is probably the number one reason why most commit to aerobics, and aerobic exercise indeed targets the heart and its vascular system. The heart is a pump that, with each contraction, forces the circulation of blood throughout the body. With each heart beat our cells receive the nourishment needed to survive as oxygen and other vital nutrients are pumped into these cites through our vascular system.