Transcript Does Weight Training Change Metabolism?

Does Weight Training Change
Metabolism?
Alter Metabolism?
 Many people believe that since muscle burns more calories
than fat, building muscle by weight lifting will noticeably
increase the body’s metabolism.
 This response is greatly exaggerated.
Metabolism
 Weight lifting has virtually no effect on resting metabolism.
 Any added muscle is minuscule compared with the total
amount of skeletal muscle in the body.
 And, muscle actually has a very low metabolic rate when it is
at rest, which is most of the time.
Metabolism
 Skeletal muscle burns about 13 kcals per kg of body mass
over 24 hours when a person is at rest.
 A typical man with a mass of 70 kg (154 lbs), has about 28
kgs of skeletal muscle.
Metabolism
 His muscles, when at rest, burn about 22% of the calories his
body uses.
 The brain and the liver use about the same number of
calories.
Metabolism
 If the man lifts weights and gains 2 kg (4.4 lbs) of muscle, his
metabolic rate would increase by 24 kcals per day.
 The average amount of muscle that men gain after lifting
weights for 12 weeks is 2 kg.
 Women will gain less.
Alter Metabolism?
 Years of weight lifting and substantial increases in muscle
mass will increase your metabolic rate.
 More muscular people burn more calories, even at rest.
 In the short-term (6 months to a year), it will not have an
effect on most people just because you cannot add enough
muscle mass to make a change.
What About Weight Gain?
 A corollary to this hypothesis is that by adding muscle you
can noticeably change you body weight.
 The idea is that when you do resistance training you may
actually be thinner yet weigh the same or a little more,
because muscle is heavier than fat.
Body Weight
 That holds a grain of truth, because muscle is more dense
than fat.
 The problem is that few people put on enough muscle in
proportion to their total body mass to make a noticeable
difference in their weight.
Body Weight
 The weight gain seen during the initial stages of weight lifting
is not caused by increased muscle mass
 As you train anaerobically, you increase muscle glycogen
stores.
Body Weight
 As you store more muscle glycogen, you store more water.
 Water is heavy
 Your weight goes up because you are storing more water
Body Composition Questions
 For every gram of CHO, 3 grams of H20 are stored in the
body.
 When glycogen stores are depleted, the loss of water leads to
a dramatic weight loss because each liter of water weighs
approximately 2 lbs.
Body Weight
 The idea that you will weigh the same or more, but you really
are thinner may be true if you work hard at weight lifting for
many months to years, otherwise, it is another myth.