Cardiorespiratory endurance is a term that's often used interchangeably with other labels such as cardiovascular or aerobic fitness. Even more casually, it's talked about in terms of how long you can sustain activity and exercise without tiring out. As you increase your cardiorespiratory endurance, your body goes through a series of changes both inside and out, usually resulting in greater health for you and a fuller, more active life.
The more oxygen your blood can carry, the more energy you can produce. That's why endurance athletes often get busted for shoveling extra oxygen into their systems. When you exercise, your body needs more oxygen to give you energy to sustain the movement. Your blood has to get it to various places faster and longer. The more you work out, the more efficient your body becomes at transporting oxygen.
The oxygen-delivery system revolves around your heart. Because it's what moves your blood through your body, your heart has to work harder during exercise to pump your blood so it can deliver the oxygen to your muscles. That's why, when you start moving, your heart beats faster. Your body knows it needs more oxygen, and it's starting to respond. The more you exercise, the stronger your heart gets and the easier it becomes for the heart to move blood throughout your body.
Your lungs also play a huge role in your cardiorespiratory endurance. They are responsible for bringing in the oxygen your body needs and removing the air you've already used, which is carbon dioxide waste. The more you exercise, the stronger and more efficient your muscles become at using oxygen, meaning they both require less and produce less waste. Your lungs won't have to work as hard, and you'll feel like it's easier to breathe, after you've developed your endurance.
How to Begin
While increasing your cardiorespiratory endurance is hard work, it's a simple concept. All you have to do is work out harder and longer. As you increase your workouts, your body develops its oxygen efficiency and you are able to keep up the movement for longer periods of time. You will go through periods of fatigue and labored breathing, but your body will get stronger and more capable with each session. Just avoid doing too much too soon or you could risk muscular injury, and always check with your doctor before you begin any new exercise program.