A number often bandied about is that an additional pound of muscle will burn 50 calories a day. What about already existing muscle? Wouldn't that muscle also burn 50 calories a day too? The 50-calorie-a-day number can’t be true if one makes the assumption that the muscle tissue you all ready had before adding that pound of muscle will produce the same calorie burn - i.e. all lean muscle tissue consumes 50 calories a day. A 155 pound man with 62 pounds of skeletal muscle would have to consume 3100 calories each day just to support his muscles.
A more reasonable assumption is that strength training will results in an increase in resting metabolism for existing muscle plus and an additional increase in metabolism for new muscle. That is the conclusion of Wayne Westcott in his article, Why The Confusion on Muscle and Metabolism?. From the results of two well designed studies he concludes:
A standard three-month strength training program may produce the following effects in previously sedentary adults and seniors:
1. Increase lean (muscle) weight by about 3 pounds.
2. Increase daily resting metabolic rate in all of the trained muscle by about 1.5 calories per pound (from 5.7 calories per pound to 7.2 calories per pound).
3. Increase overall resting metabolism by about 7 percent.
Strength training does have a significant elevating effect on resting metabolic rate, and is therefore a highly beneficial exercise for increasing daily calorie utilization and enhancing fat loss. It would appear that the metabolic increase occurs in all of the strength trained muscle tissue, and that the additional energy utilization may be about 1.5 calories per pound of muscle per day.
Interestingly both studies were conducted using brief, intense 30 minute workouts of the type we use at our facilities- Austin Personal Trainers and New Orleans Personal Training. With strength training you burn calories four ways:
1. The workout itself
2. Excess Post-exercise Oxygen Consumption (EPOC) - recovery and rebuilding muscle as a result of the workout
3. Added muscle burns additional calories
4. Existing muscle regularly trained will experience an increase in tone and an increase in resting metabolism
Not only will stronger people burn more calories at rest, people who are stronger can engage in more activities and do them for longer periods with less chance of injury creating a beneficial cycle of fat burning. Strength training is something one might want to consider if one is embarking on a weight loss program. For those will little free time you might want to consider high intensity strength training. For time spent nothing burns more calories than high intensity strength training - nothing. One study examining the effect of high intensity strength training on metabolism showed a nine-fold improvement in fat burning.