News You Can Use: More Research Updates

Here are some more research summaries from Exercise Etc.

FitBits
December 15, 2005
Exercise ETC's Review of Exercise Related Research
Compiled by Jeannie Patton, MS, CSCS

Running Faster Does Not Necessarily Result in Increased Fat Burning Rates

Low intensity endurance training is often recommended to ensure compliance and enhance fat burning, but If the goal is weight loss, theoretically the caloric cost of the activity should be as high as possible. The purpose of this study was to determine if there was a difference between energy expenditure and substrate use running the same distance at a high versus lower intensity.

Ten males and 4 females that were moderately endurance trained served as subjects. On separate days. Each subject performed a five-mile run at 70% and 95% of their individual anaerobic threshold. Energy expenditure was significantly greater during the higher intensity run, but there was no significant difference in the absolute amount of fat that was used, although the higher intensity trial used a statistically significantly greater amount of carbohydrates.

The results of this study indicate that both high and low intensity endurance exercises are effective for weight loss and fat loss. If caloric expenditure is the goal, then the time needed to reach that goal will be less with high intensity exercise versus low intensity exercise, but Fitness Professionals need to consider several other aspects when interpreting these results. The motivation of the client must be considered when recommending high intensity exercise. Clients working at higher intensities may perceive the exercise as uncomfortable and punishing, which could have an impact on adherence.

Rosenberger, Friederike. Et al. Running 8000m fast or slow: Are there differences in energy cost and fat metabolism? Medicine & Science in Sports & Exercise. 2005: 37(10), 1789-1793.


More Evidence That Strength Training Is A Viable Choice for Weight Loss

The American College of Sports Medicine and the Centers for Disease Control and Prevention recommend 30 minutes of moderate intensity physical activity at least 4 days per week. Moderate intensity is defined as physical activity that is performed at an intensity of 3-6 metabolic equivalents (METs) with an energy expenditure of 150 to 200 calories within those 30 minutes. The purpose of this study was to compare the calories burned during cardiovascular and strength training at moderate resistance.

Ten trained men performed 30 minutes of intermittent free-weight squatting at 70% of 1 repetition maximum and continuous cycling at 70% of VO2 Max. Measurements included VO2, caloric expenditure, heart rate, respiratory exchange ratio, work and rating of perceived exertion.

The researchers found that average caloric expenditure was 442 calories for the cycling activity versus 269 for the resistance activity. The subjects had a higher average VO2 for the cycling activity, and the total work was also higher for cycling than squatting. (Interestingly, perceived exertion was higher during squatting , although heart rates were identical for both cycling and squatting.)

On the surface, it appears that continuous aerobic activity results in a higher caloric expenditure than strength training for the same amount of time, but several factors must be considered: The 30 minutes of resistance training consisted of both work and rest periods so the actual time spent in work was only about 6 minutes compared to 30 minutes of continuous cycling. The work output per actual minute of exercise was almost double for the squatting exercise versus the cycling exercise. Fitness Professionals must also consider the effect of excess post-exercise oxygen consumption (EPOC,) which increases lean mass and metabolic rate and is associated with resistance exercise. When these factors are considered it appears that resistance training is a viable mode of exercise for weight management and can be used to fulfill the minimum amounts of recommended physical activity for Americans.

Bloomer, Richard. Energy cost of moderate-duration resistance and aerobic exercise. Journal of Strength & Conditioning Research. 2005, 19(4), 878-882.


Americans Living Longer Despite Increases in Obesity, Hypertension

The Associated Press reports that American life expectancy is at an all time high: 77.6 years. This is in spite of statistics that show that half of middle aged Americans have high blood pressure, 28% report "recent" low back pain, and 40% are obese. One reason for the increase in life expectancy, despite the increases in hypertension and obesity, are major advances in health care that allow people to live longer despite unhealthy lifestyles. Thanks to the increased use of cholesterol lowering drugs, cholesterol levels actually decreased, even as obesity increased. This study focused on Americans age 55 to 64, since these "near elderly" citizens represent a huge potential influence on the American Health care system. For example, in 2004 there were 29 million Americans in this age group; by 2014 there will be 40 million near-elderly Americans, thanks to the aging of the Baby Boomers.

Life Expectancy Hits All-Time High: Health Officials Say Obesity and High Blood Pressure Are Trouble Spots As reported by MSN. Mike Stobbe. AP 12-08-05 15:28 EST