An exercise is considered an endurance activity if it lasts at least 10 minutes. Swimming is no exception. As you breathe deep, kick your legs and forcefully move your arms, your cardiovascular system circulates blood and oxygen to fuel your working muscles against the water's resistance. Without a strong cardiovascular endurance system, your swim is cut short and you are left treading water.
Built for Speed
First, you determine if swimming is an aerobic exercise. Swimming fits the criteria of being an activity that is sustained, uses large muscle groups, lasts for 30 to 60 minutes and is performed three to five days a week. Your heart rate increases as your swimming speed increases and often may exceed the endurance-training zone. The way to remain within your endurance-training heart rate is to keep a pace at which you can carry on a conversation.
An Oxygen High
A tremendous amount of oxygen is required for endurance exercises. If you swim laps, you understand the need for oxygen to keep up with your elevated heart rate. At the endurance level, your body converts energy stores into usable fuel for your swim. A swimmer's body does this efficiently and has twice the endurance capacity of a sedentary person. This cardiovascular endurance is important to maintain the swim for 30 to 60 minutes.
Dare to Compare
Swimming burns a high number of calories, which is also a way to determine that it is an endurance exercise. A comparison of swimming and volleyball show the same number of calories burned during a 25-minute swim as an hour of playing volleyball. The Centers for Disease Control recommends two and a half hours a week of cardio exercises such as swimming to improve health and reduce risk of illness such as cardiovascular disease.
According to the CDC, swimmers have half the risk of death compared to sedentary people. Death risks include cardiovascular diseases, high blood pressure and diabetes. Not only do you improve and use your cardiovascular endurance, you reduce your joint impact for a comfortable workout. Swimming is also used as a test for endurance fitness since it uses large muscles and creates intensity during the extended durations.