As the fitness industry has grown, so have the myths about how and why we should exercise. With so much information available, it's often difficult to sort fact from fiction. The following are a few of these myths currently circulating. Walking or running with light weights on your arms or legs can increase your fitness level. False. By strapping Velcro-fastened weights around your ankles or carrying small hand-held weights, all you do is hurt your joints and ligaments. Plus all the excess weight does is slow you down, so you get even less benefit from the aerobic exercise. To top it off, the weight isn't enough for you to get the benefits of strength training. Swimming is the best exercise. False. While this is a great exercise, especially for people with joint problems, you can still strain your body using bad technique. It won't do much for your body shape either, unless you are working correctly and with intensity. To get the most out of swimming, it's a good idea to take a swimming course every now and then. All types of exercise can help you to lose weight. False. Calories are used up when doing activities that raise the heart rate such as running, cycling or tennis. Slow, isolating exercises such as Pilates or certain types of yoga that involve staying in one position for a few minutes will only burn a few calories. With the right exercise, you can spot reduce your trouble areas. False. Certain exercises that work your abdomen will only strengthen the muscles underneath the subcutaneous layer of fat that gives the appearance of flab. You will only lose weight by burning more calories than you put in. Where you lose it depends on your genetic makeup. In general, though, losing weight from around the waist is easier than off the hips. Exercise burns loads of calories. False. People often believe that exercising gives them a licence to eat. It does, but only if you're working out five hours a day or training like an Olympian. Even cyclist Lance Armstrong was careful about his calorie intake while training, since he only used up about 300 calories an hour during many of his training rides. In general, running or walking burns about 100 calories. But sitting still uses 50 or 60, so the extra isn't that huge. Also, another misconception is that you keep burning considerably more calories for a long time after you stop exercising. But research shows that your metabolism is really only elevated for the first five or six minutes after you stop working out and by 40 minutes, you're back to where you started. Weight machines give an all-over body workout. False. The shiny machines you see in many fitness facilities are only good for working muscles in isolation, but the body doesn't move that way. On the machines, the body is supported, so the stabilising muscles don't get a workout. This results in muscular limbs but weak core strength and stability in the spine. No pain, no gain. False. Many people still believe that aching muscles are the only signs of a beneficial and effective workout. But in fact, what this means is that you've worked above your fitness level. Your body wasn't able to supply the muscles with enough oxygen, causing a build-up of lactic acid. Also, a health study by Harvard University in the United States has found that moderate-intensity exercise has similar benefits to and improves health just as much as high-intensity exercise. The one major advantage that high-intensity exercise does have is that it saves time. It takes less time to burn the same number of calories when you are working out at a higher intensity.