Cardiovascular Fitness

This is the ability of your heart, lungs and circulation systems to bring oxygen to your muscles for your body to work more efficiently.

The faster your body can do this, the lower your blood pressure and resting heartrate will become, thus essential for overall health and wellbeing.

Many people feel that exercise will be too hard for them, however you don't need to exercise at high intensity - only 55-65% of maximum heartrate.

Guidelines for improving your CV fitness levels

FREQUENCY - 3 times a week
INTENSITY - 55-90% maximum Heartrate
TIME - 20 - 60 minutes a day  ( doesn't have to be in a single session)

The heartrate training zones on machines like Treadmill, Cross Trainer, Stationary bike etc.  are just a guide, everybody will adapt and function differently at different levels due to their physical make-up and current fitness level.
 A more realistic method to check how you are improving is to use a heartrate monitor watch. Here you can see your actual heartrate change and pump as you exercise and how it decreases when you rest. You can track how efficient your body becomes by seeing how long it takes for you to recover and what your resting heartrate reduces to over time.

Basically we just need to get moving, doing an activity that uses multiple muscle groups in different ways will get the body functioning more efficiently. Doing something that you ENJOY is of paramount importance because it will 'keep' you moving.