The Cardiovascular system Lesson Objectives: Be aware of what the cardiovascular (CV) system consists of. To understand what is meant by CV endurance. To consider how CV endurance can be measured and improved.

The Cardivascular system This is the name given to the system consisting of the heart and blood vessels that circulate and transport blood around the body.

Cardiovascular endurance This is the ability of the heart and lungs to keep supplying oxygen in the bloodstream to the body in order to provide energy to enable physical movement. So when someone takes part in activity that requires them to move for long periods of time, they need to take CV endurance into consideration and try to improve it.

During sustained activity you will notice: Increase in your breathing rate (BR) Increase in your Heart rate (HR) – pulse Increase in your blood pressure. This is because your working muscles are having more demand put upon them and so require more oxygen to provide energy. Blood pressure: the force of the circulating blood on the walls of the arteries.

Improving CV endurance: An essential requirement for participants in physical activity. Everyone should look to improve their levels of endurance or maintain them at a high standard. To do this you must make your heart and lungs work harder in order to get them to adapt to the increased demand. Your HR has to be kept at a high level for a period of time.

The following graph shows the levels your HR should be raised to relative to your age using the calculation: Maximum HR = 220-your age e.g MHR = 220 – 15 = 105

To gain full benefits of exercise you should aim to work within the aerobic zone and the training zone for at least 15 mins. Build up your effort slowly and do not do too much too quickly.

Testing CV endurance: Resting HR : a general indicator. The lower it is the better your endurance level is. HR recovery rate: The quicker this returns to your normal resting HR, the higher your endurance levels are. These 2 simple tests help you to monitor your CV endurance levels over a period of time.

Examiners tip: Questions on this topic are likely to relate to why levels of CV endurance are important and the ways in which they can be improved and measured.