Grand Pa says "i need my childhood bicycle back"

Increase health of your heart
Bicycling is a good cardiovascular exercise that could increase the health of your heart. A bike with several speeds will allow you to increase you fitness level as your cardiovascular function improves.

Release your stress
It's also great way to release your stress from daily work either if you work at home or have a regular job. You can do it inside the house with an exercise bike, but also you can take your bike out and enjoy nature.
Weight management
A 15-minute bike ride to and from work five times a week burns off the equivalent of 11 pounds of fat in a year.
Fitness
Bicycle your way to Fitness.

Some Safety needed

The most common cycling overuse injury occurs in the knees, affecting cyclists at all levels. These are caused by many factors:
Incorrect bicycle fit or adjustment, particularly the saddle.
Incorrect adjustment of clipless pedals.
Too many hills, or too many miles, too early in the training season.
Poor training preparation for long touring rides.
Selecting too high a gear. A lower gear for uphill climb protects the knees, even though your muscles are well able to handle a higher gear.

Drawback
One concern often expressed is the thought that riding in traffic exposes the cyclist to higher levels of air pollution.