CARDIOVASCULAR RESPONSES When we participate in exercise our contracting muscles require a continual supply of nutrients and oxygen to support energy production. These requirements are more intense during exercise, compared to when we are carrying out normal activities at work or when we are resting. In order to meet these demands our heart has to beat harder and faster. If these demands are repeated frequently as a result of continued training, over time our heart will get stronger.

Heart rate anticipatory response The nerves that directly supply our heart and chemicals in our blood can rapidly alter our heart rate. Before the start of exercise our heart rate usually increases above resting levels, which is known as the heart rate anticipatory heart rate. Our bodies start to anticipate that our body is going to be doing some form of physical activity and starts to prepare our body for it. The greatest heart rate anticipatory response is seen in short sprinting events. Activity response At the start of exercise, or even slightly before , nerve centres in our brain detect cardiovascular activity. These results in adjustments by our cardiovascular system to help us through physical activity by increasing the heart rate and pumping strength of the heart. At the same time regional blood flow is altered in proportion to the intensity of the activity is undertaken.

Increased blood pressure Vasodilation and Vasoconstriction Blood pressure is the pressure of blood against the walls of our arteries and results in two forces. Systolic blood pressure is when blood is pumped from the heart, through to the arteries around the body. Diastolic blood pressure occurs when the heart is relaxing. During exercise our cardiac output also increases. During aerobic exercise, oxygen consumption and heart rate increases in relation to the intensity of the activity. Vasodilation and Vasoconstriction During exercise some of our muscles (the working muscles) require more oxygen, which travels through the blood. To enable this to happen vasodilation and vasoconstriction occurs. Vasodilation happens when the capillaries that surround our muscles get bigger to enable this blood to get through. Vasoconstriction is when the capillaries around the muscles that aren’t needed are made smaller.