Aerobic endurance (also known as cardiorespiratory endurance) refers to the ability of your cardiovascular and respiratory systems to sustain moderate intensity exercise over extended periods. It is one of the five essential components of physical fitness, which can help you maintain good health.
Aerobic Activity Increases Endurance
While the word "aerobic" has commonly been thought of as a specific form of exercise, i.e. aerobic dance or aerobic activity, the official definition of the term is "in the presence of oxygen." Therefore, aerobic activity (also called "cardio") is any activity in which your heart is pumping oxygenated blood to working muscles. This pumping of oxygenated blood strengthens your heart. Over time and with sustained practice, cardiovascular exercise strengthens your heart and allows it to pump blood throughout the body more efficiently.
The term endurance refers to the ability to sustain repetitive motion over time, or as Merriam Webster says, "The ability to sustain a prolonged stressful effort or activity." In the case of aerobic endurance, the stressful activity is aerobic movement because it is placing healthy stress on your cardiovascular and respiratory system, which then allows your heart, lungs, and the body parts you use, to grow stronger and more efficient with repeated effort.
Elements Required to Improve Cardiorespiratory Endurance
To improve your cardiorespiratory endurance, there are several key elements involved.
Heart Rate
During aerobic activity, your target heart rate should be about 50 to 85 percent of your maximum heart rate. Maximum heart rate varies based on age, and you can find yours by using a heart rate calculator or consulting the American Heart Association's chart, which shows both target and maximum heart rate. When you are exercising and your heart rate remains within this target range, you are exercising aerobically and improving your cardiovascular endurance. If your heart rate is above or below the 50 to 85 percent of maximum, you are not exercising aerobically and won't increase your endurance.
The methodical raising of heart rate over sustained periods strengthens the heart and allows it to function more efficiently.
Measuring heart rate by taking your pulse during exercise tells you whether you are working within the range of aerobic activity, or if your exercise intensity is too low or too high.
Use the above-linked calculators or charts to determine whether your pulse rate is consistent with the definition of aerobic activity.
Respiration
Aerobic activity always occurs in the presence of respiration (in other words, breathing). As you breathe, your lungs provide oxygen to the blood and as you exercise, the requirement for oxygen increases, which means your breathing rate also increases. This is why when you exercise, your breathing becomes labored, and you may find yourself breathless. Your lungs are working harder to supply the oxygen required by the increased stress caused by activity.
Measuring respiration and oxygenation is complex, but as you exercise aerobically, notice whether breathing comes more quickly and breaths are deeper.
During aerobic exercise, your respiration should be deep enough and fast enough that you feel it quickening.
If you are working in a range that will increase your endurance, you won't be able to sing a song, but breathing should not be so heavy and deep that you cannot have a conversation with someone else or speak a sentence or two. In other words, if you are gasping for air or if you're singing a song, you are not working aerobically.
Repetitive Motion
In general, when you exercise aerobically you are engaging in repetitive, moderately strenuous motions that involve large and small muscle groups. This can include repetitive activities, such as walking, jogging, or swimming, or less repetitive, but still strenuous activities, such as dance. When you repetitively work a muscle by flexing, extending, pushing, and pulling, you increase the endurance of that muscle. While muscle endurance is a separate component of physical fitness from cardiorespiratory endurance, typically when you are improving one, you are also improving the other in the muscle groups you are using for the motion.
Improving Your Endurance
The best way to improve your cardiorespiratory endurance is to engage in various types of aerobic activity for 20 to 30 minutes a day, three to four days per week. In the beginning, especially if your endurance is poor, you may wish to start more slowly. The following schedules for beginning, intermediate and advanced exercisers can help you to ease your way into improving your endurance.
Beginners
Each week for the first six weeks, increase your activity by five to ten minutes.
Start with 15 minutes of mild activity in the lower range of heart rate (about 50 to 60 percent of the max). Walking or swimming may be good activities.
Complete two days per week of the activity.
Intermediate
After about six weeks, you can add days. Continue this for six to eight weeks.
Exercise for 30 minutes per day at 60 to 75 percent of your max heart rate.
Complete three to four days per week of the activity.
Advanced
After about 12 weeks, your cardiovascular and respiratory systems should be ready for full activity. Continue this indefinitely, adding intensity as your body adjusts.
Exercise for 30 to 60 minutes at 80 to 85 percent of your max heart rate.
Complete four to six days of activity per week.
Measuring Improvement
There are two ways to measure the improvement of your endurance. The first is highly subjective while the second is more precise.
Subjective: It Gets Easier
Subjectively, you can tell your endurance is improving when you notice the following things:
You breathe more easily during the activity and can talk in full sentences and don't find yourself gasping for air at a level of intensity that used to give you problems.
You can go for longer periods than you could before.
You feel fine engaging in the exercise more frequently.
Objective: Recovery Heart Rate
The way to measure your improving endurance objectively is with recovery heart rate. Your recovery heart rate is a measure of how quickly your heart rate returns to normal after exercise. You can use this process for calculating recovery heart rate. The more quickly your heart rate recovers, the better your endurance is.
Stronger Heart and Lungs
The goal of improving cardiorespiratory endurance is to strengthen your heart and lungs so that when you engage in activities, you are able to do so for longer and more easily. It's always a good idea to talk to your health care provider before engaging in any exercise program, but with all systems go, strengthening your endurance is a great way to enjoy life and get in better shape.
