Remember exercise protects against high blood pressure, diabetes, Alzheimer's, stress, depression, cancer, weight gain and many other conditions.
Try to exercise at least 3 times a week, for half an hour. If none of these exercises appeal to you, walking is great, wonderful exercise, and you don't even have to go outside to do it.
http://www.webmd.com/fitness-exercise/ss/slideshow-7-most-effective-exercises