While big chunks of America’s population continue to be ravaged by obesity, causing other problems such as cardiovascular disease and diabetes, there are many millions who choose to prevent those conditions by exercising regularly.

“The Centers for Disease Control recently estimated that only 20 percent of us get the recommended amount of daily exercise,” says Dr. Brett Osborn, author of “Get Serious, A Neurosurgeon’s Guide to Optimal Health and Fitness.”

If you’re going to exercise – which Osborn applauds – he warns that you will do more harm than good if you’ve bought into some of the myths and “conventional wisdom” that is, in fact, simply wrong. Osborn, an avid bodybuilder, shatters some of those misconceptions:

• More exercise is always better. Everyone wants more muscle and less fat, Conventional wisdom says that hours and hours of exercise will achieve those results. That’s completely wrong, Osborn says. Overkill is not only unnecessary, it can be counterproductive. You’ll get the best results with a strength-training regimen, tailored to meet your needs, which can be accomplished in three to four hours per week.
• More cardio is better than lifting. For all you chronic dieters and cardio enthusiasts out there trying to shed fat, the right strength-training program can boost your metabolism and help burn off more fat. By increasing lean muscle mass, you will increase your basal metabolic rate, BMR. Activated, contracting muscles are the body’s furnace. Excessive cardio and dieting can eat muscle tissue away, compromising this furnace.
• Women: “But I don’t want to look like a man.” Females who lift weights won’t look like men; they do not have the hormonal support to pile on a significant amount of muscle mass. Female lifters will, however, assume a shapelier figure. In fact, 99.99 percent of men older than 30 do not have the natural hormonal support to do so either. All elite professional bodybuilders use androgenic agents, including steroids.
• You need to buy “product X.” We live in a very money-based culture – so much so that we often place the almighty dollar above health. Get out of this mindset, at least regarding exercise. What counts for building muscle includes determination, intensity, consistency and safety. If you think buying the most expensive formula, training uniform or machine is necessary for reaching your potential, you’re wrong. Machines often compromise the intensity required for the body you desire.
• CrossFit is a good exercise program. If you want to build muscle, then CrossFit has many problems. CrossFit encourages ballistic movements from novice lifters, and since the program’s rise in popularity, there has been a marked increase in injury rates, which can set fitness goals back by many months. CrossFit encourages overtraining and has been linked to increased incidents of Rhabdomyolysis, or Rhabdo, which is the breakdown of muscle tissue that leads to the release of muscle fiber contents into the blood. Rhabdo can cause kidney damage. The creators of CrossFit have encouraged the Paleo Diet, a low-insulin diet. Insulin is a necessary part of building muscle.