What is an “optimal” exercise prescription?
What will bring about the greatest results for the time invested in an exercise program? 

A study by researchers at Duke University Medical Center and East Carolina University published in the November 2011 issue of the American Journal of Physiology – Endocrinology and Metabolism provides some insight. The researchers compared aerobic training to resistance training to see the impact on fat stores, along with some other health-related measures, in a group of overweight or obese inactive adults. Although both visceral fat (the fat within the abdominal cavity surrounding the internal organs) and subcutaneous fat (the fat just under the skin) were assessed, the focus was on visceral fat due to its relationship with type 2 diabetes, heart disease, and even some cancers. Researchers found that aerobic exercise including use of treadmills, elliptical trainers, and/or cycle ergometers was superior to resistance training for reducing body mass, subcutaneous fat, and visceral fat. Aerobic exercisers included an equivalent of about 12 miles per week (about 132 minutes) at an intensity around 75% of their peak oxygen uptake while the resistance training group exercised 3 days per week, 3 sets per day with 8-12 repetitions per set, for 8 different exercises.

Based on the study results, for individuals with limited time to exercise, aerobic exercise appears to be more time-efficient and effective than resistance training to reduce body weight and fat. Does this mean that resistance training is of no value?  Rushing to that conclusion is premature. Realize this study focused on very specific outcome measures and thus did not examine the effect of resistance training on improvements in other important health parameters like blood pressure or bone mass, both of which have been found to be improved with resistance training in other studies.

Bottom line: Resistance training IS important for improving strength and lean body mass, even if its role in reducing visceral fat wasn’t found in this study.  Thus, don’t throw out the concept of a balanced exercise program for overall health, which includes both aerobic exercise and resistance training. 

For a complete look at the research study, see http://ajpendo.physiology.org/content/301/5.toc.  For more information on the benefits and components of a complete exercise program, see ACSM’s Position Stand on Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory, Musculoskeletal, and Neuromuscular Fitness in Apparently Healthy Adults: Guidance for Prescribing Exercise (http://www.acsm.org/access-public-information/position-stands) or a summary of this material at http://www.healthyourwayonline.com/?s=bushman. 

Dr. Bushman is a Professor at Missouri State University and is American College of Sports Medicine (ACSM) certified as a Program Director, Clinical Exercise Specialist, Health Fitness Specialist, and Personal Trainer.  She is the editor of ACSM’s Complete Guide to Fitness & Health (Human Kinetics, 2011, http://www.humankinetics.com/products/all-products/acsms-complete-guide-to-fitness–health), a book focused on optimizing both exercise and nutrition to improve fitness and health for individuals of all ages. For more health and fitness related tips, join Dr. Bushman’s Fitness ID Facebook page (http://www.facebook.com/FitnessID) to discover, develop, evolve, and personalize your FITNESS ID. Dr. Bushman also is the lead author of ACSM’s Action Plan for Menopause (Human Kinetics, 2005,