Many exercise machines allow you to read, watch TV, or listen to music while working out. Work out at a level that feels fairly light to somewhat hard. You may be sweating and breathing hard, but not gasping for breath. Your doctor should recommend an exercise heart rate that is considered safe and appropriate for you. This may involve taking an exercise stress test to determine your peak heart rate.
Some people worry about having a heart attack while exercising.
It's true that your risk is a bit higher during a workout than while resting. Thus, resistance training can decrease the demands on your heart during work and leisure-time activities. Strength training should work all the major muscle groups in your body. Ask your doctor or other healthcare provider for exercises that stretch all the major muscle groups. In addition to a specific exercise program, you can help your heart further by increasing your activity in daily life.