Aerobic exercise beats resistance training for weight and fat loss: physical activity, such as walking, running, and swimming, seems best for losing both weight and body fat.
Previous studies suggested that resistance training was the winner in helping people lose weight by increasing the resting metabolic rate--the rate at which energy is used (calories are burned) when the body is at complete rest. The American College of Sports Medicine recommends strength training as part of a health and fitness regimen "to increases fat-free mass and further reduce health risks."
However, the effect of resistance training on fat mass remains unclear, and the Duke research team wanted "clear, evidence-based exercise recommendations" to help people lose weight and body fat.
RESISTANCE, AEROBIC, OR BOTH? To accomplish that goal, 234 (119 finished the program) overweight or obese adults, ages 18-70, were enrolled in the National Institutes of Health-funded study at Duke and randomly assigned to one of three groups:
1 Resistance training (weightlifting exercises three days per week, three sets per day, 8-12 repetitions per set)
2 Aerobic training (walking/ moving approximately 12 miles per week)
3 Aerobic exercise and resistance training (three days per week, three sets per day, 8-12 repetitions per set, plus 12 miles of aerobic exercise per week)
After the eight-month trial, the outcomes were measured in terms of body composition, weight, waist circumference, cardiopulmonary fitness, and strength and compared to those taken when the study began. t
* The aerobic exercise-only group averaged 133 minutes per week training and successfully lost weight.
* The resistance-only group gained weight because of an increase in lean body (muscle) mass.
* The resistance training-only group spent about 180 minutes/week exercising without losing any weight.
* The aerobic-plus-resistance-training group lost more weight than those who did resistance training only, and recorded the largest decrease in waist size. But they did not show more significant reductions in fat mass or body mass than the aerobic group, and spent twice the time exercising as both other groups.
TIME TO RECONSIDER. "No one type Df exercise will be best for every health benefit," says research coordinator Leslie Willis, MS, exercise physiologist at Duke University "However, it might be time to reconsider the conventional wisdom that resistance training alone can induce changes in body mass or fat mass due to an increase in metabolism. Our study found no change."
AGE-SPECIFIC EXERCISE. Recommendations for exercise are age-specific, researchers note. Older adults have muscle atrophy; resistance training can offset that loss. Younger adults in good health who want to lose weight would see better results doing aerobic training. Resistance training is good for building muscle strength and muscle endurance, but it's not good for burning fat or losing weight.
The Duke study is believed to be the largest randomized trial ever conducted to measure body composition before and after three modes of exercise, yet almost half of the subjects dropped out. Finding ways to keep people engaged in a weight loss/ fat loss program may be as important as discovering which type of program is best for each individual.
* Jumping rope
* Exercise machines
RELATED ARTICLE: THE VIEW FROM DUKE
CONNIE W. BALES, PhD, RD, 6 Professor, Department of Medicine, Duke; Associate Director, GRECC, Durham VA Medical Center
"The suggestion that lifting weights to build up the muscles will rev up metabolism, burn extra calories, and induce weight loss is an attractive one. It's commonly accepted as true and makes sense, too. But there is little proof that increasing muscle by resistance training burns enough calories to cause an energy deficit and reduce body fat. This study clearly illustrates that aerot: exercise trumps resistance exercise for weight loss. As noted by Dr. Willis, resistance training offers a number of important benefits. But IF the most important body habitus problem is excessive body fat and IF the most urgent health priority is weight reduction, then for those whose exercise training time is limited, it should be devoted to training of the aerobic type."
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|Title Annotation:||NUTRITION & FITNESS|
|Publication:||Duke Medicine Health News|
|Date:||Mar 1, 2013|
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