Resistance training is not effective in weight loss or body fat reduction without dietary modification.
The best outcomes for weight loss and body fat reduction come from dietary modification.
Physical Activity is most useful for weight management and preventing weight regain and maintaining body weight after weight loss. Physical Activity will promote clinically signification weight loss.
The cardiac and direct caloric expenditure associated with resistance training is minimal. The muscle mass increase from resistance training may (not proven in clinical trials) increase total daily energy expenditure.
A 200 lb. male Running for 15 minutes will burn about 150-200 calories.
A 200 lb. male can eat 3000 calories per day and maintain their current weight.
Strength Training has no where near the calorie burn as running. It is so little it is too difficult to measure. There are many that incorrectly believe a heart rate monitor, that estimates (over estimates typically) calorie burn, can be used while strength training. Not true.
The amount of calories burned in a strength training workout is about 10 potato chips at best (10 potato chips = 100 calories).
It was mentioned in this question, some resistance exercises will increase heart rate. This is not necessarily a result of cardio pulmonary response. An increase in adrenaline will stimulate heart rate. For example fright and stress increase heart rate but DO NOT increase cardiac output volume.
The hemodynamics of cario respiratory exercise vs. anaerobic strength training are very different. So complex, no one really knows precisely the metabolic process that causes the heart to beat faster when exercising. Some very good theories, but no one knows for sure.
There was a very significant study done in Denmark recently where they found the increased heart rate did not increase the heart stroke volume because the blood vessels dilated (vasodilatation).
Link: Peripheral Vasodilatation Determines Cardiac Output in Exercising Humans
- Ten healthy and recreationally active male subjects participated in
- a catheter was placed in the brachial (4 subjects) or femoral (6
subjects) artery of the experimental leg
- another catheter was placed in the pulmonary artery going in
throughout the jugular vein
- During exercise, cardiac output is regulated to match oxygen delivery
to the metabolic demand.
- This study evaluated the role of heart rate and peripheral
vasodilatation in the regulation of cardiac output during exercise.
- heart rate was increased by atrial pacing in 10 healthy male
individuals during three different conditions: at rest, during
exercise, and during femoral arterial ATP infusion at rest.
- Increasing the heart rate by atrial pacing by up to 54 beats per min
did not increase cardiac output in any of the three given conditions
as there was a proportional decrease in stroke volume.
- These results indicate that cardiac output is regulated by changes in
peripheral vasodilatation, whereas an increase in heart rate is less
The increased heart rate that occurs with cardio respiratory exercise is the result of the need for increased cardiac output to transport oxygen to the muscles. The heart must pump more blood to meet the energy demand of the activity. Heart rate increases because of a demand for blood volume directly related to hemodynamic performance, pulmonary respiratory gas exchange adequacy, and muscle metabolism efficiency.
The increased heart rate that occurs with strength training is the result of changes in intrathoracic pressure and an increase in afterload stress. There is no corresponding increase in cardiac output, and thus only a modest increase in oxygen uptake. Heart rate increases because of a perfusion pressure gradient not relative to body tissue's current metabolic needs.
Just by definition anaerobic exercise does not have a "cardio respiratory" component.
1. (of an organism or tissue) living in the absence of air or free oxygen.
2. pertaining to or caused by the absence of oxygen. -http://dictionary.reference.com
Energy for anaerobic exercise comes in the form of chemical transformation involving energy phosphates, glycolysis, and not oxygen.
Unlike cardio respiratory exercise, the increased heart rate during strength training DOES NOT reflect either an increase in oxygen uptake or a significant increase in caloric expenditure. Moving quickly from machine to machine to keep the heart rate elevated does not change this fact. It is still a pressure load, not a volume load.
Resistance training with a high protein diet has shown some improvement in body fat reduction. Resistance training alone without dietary modification, has not been proven to reduce body fat.
Research studies on the subject are sparse and split on the subject. Some studies reported a modest loss in body fat with resistance training for a period of between 16 and 26 weeks. Other studies showed no reduction in body fat for resistance training periods between 12 and 52 weeks.
One study observing gender and age found fat reduction only in older men and no difference in body composition for young men or women of any age.
There are slightly more studies showing an increase in lean body mass without dietary modification.
Strong Statement from American College of Sports Medicine.
The American College of Sports Medicine Position Stand makes a strong statement with an Evidence Statement Category A (significant Randomized Trials with significant participants to support):
"Resistance training will not promote clinically significant weight
loss". - American College of Sports Medicine Position Stand Evidence Category A (A = significant studies with significant participants)
A training plan for weight loss and body fat reduction calls for a cardio respiratory regimen at about 60% of Maximum Heat Rate. The length of a cardio work out is dependent on current aerobic capacity, and resting heart rate. Maximum heart rate is age dependent.