[PowerManDL]

Originally Posted by Dr.SusanHarmonyPhD

Running burns more CALORIES than walking. But that doesn't mean it burns more FAT.

Because different kinds of muscle cells are active during vigorous movements and gentle movements and because these fibre types each burn a different fuel, it is possible to burn a huge amount of fuel while using up a TINY quantity of FAT.

Sugar is burnt by muscle fibers that produce powerful movements. Burning sugar makes you TIRED and HUNGRY,so that you need to stop for recovery and eat more.

The fibres that burn FAT are 'fatigue resistant' ; using them won't make you weary, or increase you appetite. They don't produce Lactic Acid (a breakdown product of sugar) so your legs won't feel 'rubbery' . You can keep a fat burning activity going indefinitely.

Dr. Harmony, may I ask what your degree and experience are in?

Because this is grossly incorrect and oversimplified -- not just from a physiological standpoint, but from the practical standpoint of anyone working in the field.

Are you aware of the concept of "insulin sensitivity", or a regulatory molecule called AMP-activated protein kinase, and specifically how these variables are acutely affected by exercise?

I would suggest spending some time on Pubmed reviewing the acute after-effects of high-intensity exercise both on AMPK activation and on calorie expenditure (to include substrate utilization, as glycogen/glucose or as fatty acid oxidation). You'll be somewhat surprised at the results, I think, considering what you've written here.

Most activities use BOTH fibres types but you can 'tip the balance' by working more gently (using more fat because you use less sugar ) for longer , or by working out vigorously (more sugar) in short bursts.


By working gently enough to keep going continously , you can EASILY BURN MORE CALORIES in a day than by doing short , exhausting sessions. (The processes involved in 'recovery ' also mainly burn sugar , so 'elevated metabolism' during rest is NOT helping to burn fat either

Dr, I would assume you have numbers from peer-reviewed sources to support this claim?

If you do, I certainly would like to see them. Because high intensity work will always burn more calories; this is simply not a matter that can be contested.

You're also not taking context into consideration, speaking from a rather narrow-minded viewpoint which can be challenged both with research and with empirical observation.

By working more gently your body will 'capillarise' more effectively (building new blood vessels) and control the blood flow better in the vessles its already got. By building up the capillaries in your Cardiovascular system , you will improve the avilablity of oxygen to your muscles.

This is irrelevant unless one is an endurance athlete.

Walking fast can burn more sugar than running slowly. But walking slowly burns more fat than either of these. Bottom line, for fat loss lift weights varying rep ranges and go for long walks .

Walking slowly burns more fat as a proportion of substrate used.

Walking fast and running burns more total calories.

What's the higher number:

80% of 200
40% of 600

The first example is aerobic activity. The second is high-intensity activity.

And to the sprinter's physique comments you make. Have I ever seen a fat sprinter. SURE I HAVE. Did ever see the guys in the NFL? They sprint and many are fat. Do a google search of Masters Sprinters - many are fat. The Olympic sprinters physiques are the result of WEIGHT TRAINING NOT sprints.

Now do a google search of the imgaes of hunter gatherer types who WALK. THEY are LEAN. They don't sprint much, if at all.

Lean, and not at all muscular.

You haven't defined any goals in your context-less statements.

Not to mention incredibly over-simplified, and not taking into account other causal factors.

As far as observational evidence look at the great health of Fauja Singh a 97 year old a vegetarian distance runner and a British man named Martin who is 101 years old and full of energy. You will hard pressed to find anyone as well off as them at that age.

Red herring. "Most" people seeking fitness are after a muscular physique with low bodyfat levels.

Again, you've defined no context, simply choosing to strawman the argument.

There is no scientific evidence the sprint program you propagate leads to a longer healthier life. Our ancestors were long distance runners.

Another red herring. This has nothing to do with the point; improved body composition is related to, but not the same thing, as improved health.