Exercise that develops your heart and lungs is called cardiovascular or aerobic fitness. Indeed, many people consider cardiovascular fitness to be the most important component of a workout program.
Protecting your heart and lungs is crucial, with cardiovascular illnesses the number one killer in modern society.
The range of exercises is vast – everything from running to rowing, skipping to swimming, so read the guidelines to get the lowdown on the best way to perform the various exercises.
The great thing about cardio exercise, is you can generally perform it everyday, as unlike weight training for your muscles, these will need rest to recover and rebuild stronger.
With cardio work, if you train smartly then you can train your body to work different muscle groups whilst always working that most important muscle in your body - your heart.
Triathletes do this well, they will often train on the bike one day, then run the next with some swimming maybe inbetween.
Aim to vary your cardio in order to improve your all-round aerobic ability, remembering to always listen to your body, so if you feel tired, then maybe take a rest day, or look at what you had to eat the day before.
If you make your cardio fun and try and train with a partner, then chances are you will get far more out of it...
Reading the notes on aerobic training will give you guidelines on how to exercise at the correct level.