Jonny Bowden, author, nutritionist and weight loss coach cuts through all the misconceptions about diet and fitness to help you transform your body, your health and your life.

OK, I admit it -- I've not been a fan of long mindless aerobic exercise, certainly not when it comes to weight loss. Recently I wrote a piece -- "The Problem with Cardio"-- that might have led you to believe I think cardio is a waste of time. That's not actually true. I think that aerobic exercise is way oversold as a weight-loss strategy, and truth be told, most people could get positive calorie burning effects in a much shorter time with high-intensity interval training. But just because jogging an hour a day may not be the most effective way to lose weight, doesn't mean you should abandon your cardio work.

Not long ago, scientists at McMaster University Department of Medicine, Health Sciences and Rheumatology Division, compared the findings of 17 studies examining the effects of exercise on anti-aging and the immune system. They wanted to answer the following question: What, if any, are the effects of regular aerobic and/ or resistance exercise on the immune system in healthy older adults?

They looked at these studies with a very critical eye, extracting only results that met very rigorous critera. Their conclusion: Aerobic exercise appears to be a friend of the immune system.

OK, remember, these guys are scientists and tend to couch their findings in very conservative terms. But considering the incredibly rigorous standards they applied to their review of the research, the conclusion is pretty impressive. Coupled with all the other benefits we know even moderate aerobic exercise can offer -- on the brain, for example, as well as on blood pressure, mood, well-being and the circulatory system -- there's no reason to abandon those 30-minute a day walks, just because they may not be the best way to go when it comes to losing weight.

And by the way -- though daily moderate-intensity exercise (like walking) may not be the best way to lose weight, it may be an essential component to keeping weight off. Findings from the National Weight Control Registry, which follows people who've successfully lost a minimum of 30 pounds and successfully kept it off for a minimum of a year, show that approximately an hour a day of moderate intensity exercise is one of the key strategies for weight maintenance.