|Space||Pause/Play video playback|
|Enter||Pause/Play video playback|
|m||Mute/Unmute video volume|
|Up and Down arrows||Increase and decrease volume by 10%|
|Right and Left arrows||Seek forward or backward by 5 seconds|
|0-9||Fast seek to x% of the video.|
|f||Enter or exit fullscreen. (Note: To exit fullscreen in flash press the Esc key.|
|c||Press c to toggle captions on or off|
How the Body Responds to Exercise
Exercise changes not only the way you look on the outside, but also the way your insides work. For example, blood vessels become more elastic when you exercise. This means they can easily expand to allow more blood to flow while you are exercising. They can also narrow when you stop and the blood flow goes back to normal.
In this video, watch how a group of people improved their fitness levels by training for and running a race. They started out with average or below-average fitness and became marathon runners. Click on the left to watch the video.
After you watch the video, list three changes that occur in the body as a result of exercise.