Your intensity level is key to how many calories you burn and to the effects of your workout. You should always be aware of how hard you are working out. Try using a heart rate monitor to continually be in touch with your level of intensity. You can also measure your workout with your perceived exertion.   Make sure you are in the “fat burning” aerobic zone by paying attention to your body–your jaw should be dropped, breathing through your mouth, lightly sweating, only able to utter about 35 words in a row. If you can stay in this target zone while watching your favorite TV sitcom, that’s great!   Reading a book or magazine can be more difficult. Sometimes you have to slow down too much in order to concentrate on the small words, and your workout intensity suffers even though you may not notice. Not to mention, if you are concentrating too hard on reading words while moving up and down, you could slip or trip and your safety could be at risk. Try using the incline on a treadmill or elliptical machine at a slower pace. The incline increases the use of large muscle groups in the legs and burns calories–while allowing you to go at a slower pace so you can read.   Music is also a great motivator for many people. Pop in the right CD or use your mp3 player and create a music play list that motivates you. I have different play lists for different moods and forms of exercise, and I notice my effort increases when I’m into my music!   The bottom line is to go ahead and entertain yourself…but don’t forget to be aware of how hard you are working.