Re: Short Bursts of High Intensity Exercise

[Guest guest]

This is pretty logical if you think about energy metabolism during endurance

type activities.

The " wall " a classic marathon mile 20+ characterization of how it feels to run

out of stored glycogen can be pushed out two ways.

First you increase your amount of glycogen stored, secondly you improve your

efficiency of burning fat and thus conserving glycogen

since we typically only have a few thousand Kcal of Glycogen stored despite

carrying pounds and pounds of fat (except for you know

who :-).

A short burst type exercise would preferentially deplete glycogen. Repeated deep

depletion of glycogen will stimulate the body to

increase storage capacity. However this will do nothing to improve fat burning

efficiency which is also important for maximum output

during endurance events.

I can easily imagine an experimental design that demonstrates improved glycogen

stores for brief exercise. I suspect this is of

limited utility for actual endurance training which already suggests working

both mechanisms (speed work and slow runs). It's like

doing the speed work only. OK if all you want to do is run sprints. I guess it

comes down to how you define endurance. Such training

will allow you to run more sprints, but won't fully prepare you for endurance

activity.

Perhaps more important how does glycogen storage capacity impact CR goals.

Increasing glycogen stored will actually prolong the time

it takes for transition to fat metabolism (ketosis) during fasting. I don't know

if wide meal spacing approaches a true fast but if

it does this could make it harder to get there.

In general a CR friendly exercise doesn't burn calories. Likewise mother nature

rarely gives you something for nothing. Be sure this

is really a CR positive. Less is less.

JR

-----Original Message-----

From:

[mailto: ]On Behalf Of Rodney

Sent: Thursday, June 16, 2005 4:19 PM

Subject: [ ] Short Bursts of High Intensity Exercise

Hi folks:

About a couple of months ago a study was posted here which showed

IIRC that cycles of short, thirty second, bursts of exercise at full

speed, with intervening four minute rest periods was just as

effective at improving endurance performance as forms of exercise

that involved much higher levels of caloric expenditure.

Can anyone tell me where I can find that study? I searched the

archive using the word 'exercise' and did not find it. Thanks.

Rodney.

[Guest guest]

Hi JR:

I guess I am looking at this from the point of view that we on CR are

hoping to become elderly people eventually, and to both survive for a

long time being elderly, and be physically capable of doing what we

want to do when we are elderly - including being nimble enough to

avoid falling and breaking bones.

So, elderly people need some stamina, but not that of an olympic 10k

contender; some strength, but not that of a professional weight

lifter; and reasonable flexibility, but not that of a contortionist.

And we would like to be able to achieve this with the smallest

expenditure of extra calories.

I wonder how far " short bursts of high intensity exercise " totalling

about nine minutes a week (seven sessions every two weeks, with five

30-second bursts in each session) would go to satisfy these

objectives.

Rodney.

--- In , " " <crjohnr@b...>

wrote:

> This is pretty logical if you think about energy metabolism during

endurance type activities.

>

> The " wall " a classic marathon mile 20+ characterization of how it

feels to run out of stored glycogen can be pushed out two ways.

> First you increase your amount of glycogen stored, secondly you

improve your efficiency of burning fat and thus conserving glycogen

> since we typically only have a few thousand Kcal of Glycogen stored

despite carrying pounds and pounds of fat (except for you know

> who :-).

>

> A short burst type exercise would preferentially deplete glycogen.

Repeated deep depletion of glycogen will stimulate the body to

> increase storage capacity. However this will do nothing to improve

fat burning efficiency which is also important for maximum output

> during endurance events.

>

> I can easily imagine an experimental design that demonstrates

improved glycogen stores for brief exercise. I suspect this is of

> limited utility for actual endurance training which already

suggests working both mechanisms (speed work and slow runs). It's like

> doing the speed work only. OK if all you want to do is run sprints.

I guess it comes down to how you define endurance. Such training

> will allow you to run more sprints, but won't fully prepare you for

endurance activity.

>

> Perhaps more important how does glycogen storage capacity impact CR

goals. Increasing glycogen stored will actually prolong the time

> it takes for transition to fat metabolism (ketosis) during fasting.

I don't know if wide meal spacing approaches a true fast but if

> it does this could make it harder to get there.

>

> In general a CR friendly exercise doesn't burn calories. Likewise

mother nature rarely gives you something for nothing. Be sure this

> is really a CR positive. Less is less.

>

> JR

>

> -----Original Message-----

> From:

> [mailto: ]On Behalf Of Rodney

> Sent: Thursday, June 16, 2005 4:19 PM

>

> Subject: [ ] Short Bursts of High Intensity Exercise

>

>

> Hi folks:

>

> About a couple of months ago a study was posted here which showed

> IIRC that cycles of short, thirty second, bursts of exercise at full

> speed, with intervening four minute rest periods was just as

> effective at improving endurance performance as forms of exercise

> that involved much higher levels of caloric expenditure.

>

> Can anyone tell me where I can find that study? I searched the

> archive using the word 'exercise' and did not find it. Thanks.

>

> Rodney.

>

>

>

>

>

>