Before your workout, warm ups are useful to help prepare your body for activity. In the warm up, we should think about two different things:
1. Raising your pulse. Think jogging on the spot or star jumps, something that gets you moving. This will increase blood flow to the muscles and prepare the cardiovascular system.
2. Think about mobility which will be moving the joints you are going to be using through the range they will work in. For example, for a runner, you may do ankle circles and hip swings.
After your workout, cool downs are a great way to decrease the intensity of the exercise and return our heart rate and cardiovascular function to normal. A slow walk after exercise or doing some light stretching can be beneficial.