You do not need to exercise:

Unless you want to achieve optimum health or at least good health there may not really be a good reason for you to exercise. Despite the fact that our bodies are the results of many generations of physically active people we may have pretty decent health as very sedentary folks, at least until middle age or later.

Our ancestors did not need to go to the gym or health club (none of which existed) because they were up and active daily taking care of life's necessities. A day of gathering food, caring for off spring, protecting the family from predators and taking care of other family needs was physically as well as emotionally demanding.

But think of the huge advantages:

• no outlandish electrical bills or other utilities
• no hassle with the cable companies
• no worry about whether to get the latest I-Phone, problems with computers, I Pads, tablets, remotes, etc.
• no frustrations with Congress or politics or ISIS
• no worry about good carbs, bad carbs, good fats, bad fats, pesticides, insecticides, etc. in our food supply or concern about the hazards of processed foods.
• no hassle about medical care and insurance deductibles, networks, which Dr. you could see
• no politicians telling you what size of slurpy you could buy with your own money

On the other hand there were:

• very short life spans
• diets limited only to what could be grown, caught or killed
• cooking only over a fire you had to build
• air conditioning consisted of trying to find a breeze or use a fan
• heating was only from building a fire in a protected place
• the main need for your children was you teaching them how to survive
• no immunizations, no antibiotics for infectious diseases, no anesthesia for surgery
• no knowledge of how to avoid the spread of disease
• no x-rays, CT scans or MRIs to evaluate injuries and medical problems

So we have these bodies genetically programed to be physically active to have maximum function. This include an estimated 75 trillion cells all of which have dozens of functions and require movement and nutrients in order to help them move nutrients into the cells and to move toxins and metabolic products out. It seems that all systems that produce energy must have an exhaust system to get rid of by products that were used to produce energy and are now waste materials. Physical activity seems to be a must to give our cells the maximum ability to do these things and to produce energy and to achieve optimum health.

So like most things in life we have some choices:

• With average genes we can usually enjoy average health until sometime around 40 without much regard for our nutritional intake or exercise level
• We can usually have pretty good health with reasonable energy level and infrequent illness with intermittent exercise and modestly good food choices
• We can learn about out body's needs and supply them and will be able to achieve optimum health which includes having good immunity and resistance to infectious diseases and cancer. No one should make these choices for us because it requires giving up temporary pleasures for long term gains and it is O.K. if we choose not to do that. To achieve financial comfort or to achieve optimum health require similar decisions and trade offs.