From: bear@tigger.cs.Colorado.EDU (Bear Giles)
Subject: Re: Starting to Exercise: Advice wanted
Organization: National Oceanic & Atmospheric Adminstration / Boulder Labs
Date: Tue, 28 Jul 1992 01:04:14 GMT

In article <1992Jul27.195913.25975@inmet.camb.inmet.com> mazur@inmet.camb.inmet.com (Beth Mazur) writes:
>In article <1992Jul25.002149.3342@colorado.edu> bear@tigger.cs.Colorado.EDU (Bear Giles) writes:
>>There are two points to remember:
>>
>>1) You lose a _lot_ more fat with sustained exercise.  It takes ~20
>>   minutes of sustained exercise to burn off your blood sugar and
>>   gycol (?, stored in liver) before your body will start to directly
>>   metabolize fat.  Shorter exercise only has a secondary effect
>>   (you reduce the amount of 'stuff' available to put into fat cells).
>>
>One major point to remember.  There is really no true consensus about
>any of this.  Ya picks your guru, and you go with what makes sense.
>
>For example, Covert Bailey (yeah, I'm a disciple :-) essentially contradicts
>the above in The New Fit or Fat.  What he says is that you burn fat all
>the time, and the point of exercise is to get your body to burn even
>more fat all the time (as he calls it, making you a "better butter burner").
>
>Anyways, one of the points he mentions is that many overweight people would
>in fact be better off exercising 12 minutes *at their target heart rate*
>several times a day than doing a longer stint of exercise.  

Odd, I remember him saying basically the same thing I said.  (Well, it
was in a different segment of his program...)

There are two phenomena at work here: the first is the effects of a
raised metabolism due to _any_ exercise.  Well, not quite any exercise;
as you get into shape it's harder to reach your target heart rate with
a fixed activity.

For instance, my daily bike ride to/from work takes 12/20 minutes (I take
different routes due to the presence of a steep hill!) but I doubt I
reach my THR for more than a few minutes -- I'm compelled to ride slowly
(on multi-use paths), waiting for a traffic light, coasting downhill, etc.
I've seriously considered riding out-of-the-way just to get enough 
exercise commuting, but Boulder is just too small!  (Seriously, I could
get the distance with on-street bike lanes but I then have _longer_
traffic waits since these lanes are along minor streets).

This may account for a few hundred calories a day, a non-trivial
amount.  But, in contrast I rode by bike nearly 30 miles at lunch
today and burned _at least_ 1500 calories (according to Kenneth
Coopers book, but he quoted figures for someone 150 lbs riding 13 mph;
I weigh 205 lbs and averaged over 17 mph -- I estimate it was closer to
_2600_ calories).  The additional hundred calories lost since I didn't
break the ride into several pieces are negligible.

>So who really knows?  I think the best advice is to do what you'll stick
>with and not worry so much about what is "the true way."  We're all
>individuals, and if anything is really true, it's that what is the "the"
>way for one person is not necessarily what is true for someone else.

I agree, but people should also be aware that circumstances change.
Something that works for a sedentary person with over 50 pounds to
lose will _not_ work when that person has become fairly active and
is trying to lose the final 20 pounds.  Contrawise, stuff that active
person can shrug off could kill the sedentary person... or at least
make them wish they were dead!  :-)

(Before somebody asks, it is possible to be moderately overweight
(20 pounds, arguably closer to 30 pounds) and still be in fairly
good shape.  Being 6'2" helps a lot, but mostly it's because my
weight problem has a physiological component which causes mild
weight swings (generally ~10 pounds, but for some unknown reason
the last one was considerably larger)).

(Also, buring 2600 calories at once is not a panacea since I still
have to watch my nutrition carefully; probably more carefully than
most people.  Dizziness, for instance, could be fatal if it struck
while I was riding in heavy traffic.  This means I have to eat
quite a bit more, losing weight slower than you might first expect).

 
Bear Giles
bear@fsl.noaa.gov
(p.s., e-mail may bounce since we're reorganizing our systems).