Trouble Commuting.

Quoted message said:

juice. Wonderful though I think coffee is, it's a diuretic (actually dehydrates you to some
extent) so not necessarily the best thing before a big ride.

I have always thought so but read recently that it is not significantly so.I would say it makes me
pee. Did anyone notice where I read this? (Cycling plus or Cycle probably.)and any references to the
study quoted? TerryJ

Thus spake "Terry J" <[email hidden]>

Quoted message said:

Quoted message said:

juice. Wonderful though I think coffee is, it's a diuretic (actually dehydrates you to some
extent) so not necessarily the best thing before a big ride.

Quoted message said:

I have always thought so but read recently that it is not significantly so.I would say it makes me
pee. Did anyone notice where I read this? (Cycling plus or Cycle probably.)and any references to
the study quoted? TerryJ

I remember, when I did an introductory Sports Medicine course, 10 years ago, one of the lecturers
stated that the latest research suggested that caffeine did not act as a diuretic if the subject was
exercising or dehydrated. (IIRC!)

Isostar has contained significant amounts of caffeine for several years and this is why I avoided it
when long-distance cycling. I did not want disturbed sleep after a long ride...

--
Helen D. Vecht: [email hidden] Edgware.

Helen Deborah Vecht said:

Isostar has contained significant amounts of caffeine for several years and this is why I avoided
it when long-distance cycling. I did not want disturbed sleep after a long ride...

I bought some a couple of weeks ago, for the first time in a couple of years. The tub has "New
Formula" emblazoned across it, and I was pleasantly surprised to see that it no longer
contains caffeine.

--
Danny Colyer (remove safety to reply) ( juggler.netdannyOpen ↗ ) Recumbent cycle page:
speedy5.freeserve.co.ukrecumbentsOpen ↗ "He who dares not offend cannot be honest." -
Thomas Paine

Quoted post said:

Originally posted by Tim Woodall
On Mon, 19 May 2003 18:41:44 GMT,

Tenex said:

Tim Woodall wrote:

557*4200/3600 = 650W.

Is that right? 650W sounds awfully high for trundling along the flat at 16mph. Isn't that more "Lance going up a mountain" power?

Cheers,

Andy

Helen Deborah Vecht said:

Isostar has contained significant amounts of caffeine for several years and this is why I avoided
it when long-distance cycling. I did not want disturbed sleep after a long ride...

Why on earth would they do that ? Wouldn't the diuretic effects of the caffeine be just what you
wouldn't want ?

In message <[email hidden]>, Andy Dingley
<[email hidden]> writes

Quoted message said:

Helen Deborah Vecht said:

Isostar has contained significant amounts of caffeine for several years and this is why I avoided
it when long-distance cycling. I did not want disturbed sleep after a long ride...

Why on earth would they do that ? Wouldn't the diuretic effects of the caffeine be just what you
wouldn't want ?

The International Olympic Committee considers caffeine a performance-enhancing drug but you would
have to consume quite a lot (equivalent of 6 to 8 cups of coffee) in a short time to get a ban.
Caffeine is thought to boost performance by forcing the body to use fatty acids for fuel, conserving
glycogen and delaying fatigue. It may also increase the force of muscle contraction and aid some
asthmatics by widening blood vessels in the lungs. Marathon runners quite commonly drink diluted,
defizzed cola during races.
--
Michael MacClancy

andy_welch said:

Tim Woodall said:

Tenex said:

Tim Woodall wrote:

557*4200/3600 = 650W.

Is that right? 650W sounds awfully high for trundling along the flat at 16mph. Isn't that more
"Lance going up a mountain" power?

Consider that involves one hour's effort of moving approx. 170lbs. Doesn't seem too high.

OTOH, I'm not sure Tim was being complimentary about my rowing performance, which I think is a
useful means of burning calories at almost twice the rate of 16 mph cycling. ;-)

On Wed, 21 May 2003 09:47:17 GMT,

Tenex said:

andy_welch said:

Tim Woodall said:

On Mon, 19 May 2003 18:41:44 GMT, Tenex <[email hidden]> wrote:
> Tim Woodall wrote:
557*4200/3600 = 650W.

Is that right? 650W sounds awfully high for trundling along the flat at 16mph. Isn't that more
"Lance going up a mountain" power?

AIUI, 650W is fuel burned (i.e. calories consumed). At 25% efficiency this is about 160W
power output.

Quoted message said:

Consider that involves one hour's effort of moving approx. 170lbs. Doesn't seem too high.

OTOH, I'm not sure Tim was being complimentary about my rowing performance, which I think is a
useful means of burning calories at almost twice the rate of 16 mph cycling. ;-)

Wasn't intended to either be or not be complimentary. You are comparing 5 mins on a rowing machine
(at I assume a high effort) with a gentle trundle on a bike. Based on the same table I burn
something like 700 cal/day just commuting. This works out at about 65cal per 5 mins, 816W or,
assuming 25% efficiency just over 200W power output.

Of course, my commute isn't completely flat (gains about 150 feet in 8 miles) with some (minor) ups
and downs in the middle. While this doesn't seem like a lot, I regularly average 20mph+ on the way
home and on a couple of occasions averaged 25mph+[1] (probably with a tail wind as well :-) while I
rarely manage 20mph on the way to work (I'm also not prepared to push quite as hard on the way to
work as I don't want to get too hot)

Regards,

Tim.

[1] Unfortunately I didn't time my fastest ever journey. All I know is that from getting up
from my desk to get changed to getting into the house (after putting the bike in the shed)
was 25 minutes.
--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

tjw.hn.orgtjw.hn.orgOpen ↗ locofungus.btinternet.co.uklocofungus.btinternet.co.ukOpen ↗

Tenex <[email hidden]> wrote:
: andy_welch wrote:
:>
:> Is that right? 650W sounds awfully high for trundling along the flat at 16mph. Isn't that more
:> "Lance going up a mountain" power?

: Consider that involves one hour's effort of moving approx. 170lbs. Doesn't seem too high.

650W is low since it's based on calories used (ie work done by the body, most of which is
wasted as heat).

If you could get 650W sustained down through the wheels OTOH then you'd be kicking everyones [censored]
(Lance sustains ~450W for an hour I believe).

Arthur

--
Arthur Clune clune.orgclune.orgOpen ↗ Power is delightful. Absolute power is absolutely delightful -
Lord Lester

Tim Woodall said:

Wasn't intended to either be or not be complimentary. You are comparing 5 mins on a rowing machine
(at I assume a high effort) with a gentle trundle on a bike.

I wasn't making a comparison, I just thought that 3-400 calories per hour suggested wasn't a lot
when I burn ~85 in 5 minutes rowing. I assumed the figure must be higher.

You provided a higher figure of 557 which sounded more reasonable. "fairly mediocre" didn't sound
too complimentary when used as a comparison.

My point was simply that the original suggestion was an underestimate.

Quoted post said:

Originally posted by Tim Woodall
On Wed, 21 May 2003 09:47:17 GMT,
Tenex <[email hidden]> wrote:

AIUI, 650W is fuel burned (i.e. calories consumed). At 25% efficiency this is about 160W
power output.

Ah silly me. Comparing apples and oranges again. So 650W of work done by me only puts 160W through the wheels (as Arthur puts it). Not exactly an efficient cycling machine am I?

Cheers,

Andy

andy_welch said:

Tim Woodall said:

On Wed, 21 May 2003 09:47:17 GMT, Tenex <[email hidden]> wrote: AIUI, 650W is fuel burned (i.e.
calories consumed). At 25% efficiency this is about 160W power output.

Ah silly me. Comparing apples and oranges again. So 650W of work done by me only puts 160W through
the wheels (as Arthur puts it). Not exactly an efficient cycling machine am I?

25% feels low to me but numerous websites seem to agree. OTOH, the brain uses a lot of the oxygen
(and hence fuel) consumed by the body and doesn't do a lot to improve your speed. (Mind over
matter excluded)

It would be interesting to know what the efficiency of the cycling muscles was (including digestion
losses) but excluding the general running of the body.

The upper limit for efficiency of a car engine is around about 60%. Getting the real figure is much
more difficult and, even then, does the various figures banded about include losses by using the
AC/Lights etc?

Regards,

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

tjw.hn.orgtjw.hn.orgOpen ↗ locofungus.btinternet.co.uklocofungus.btinternet.co.ukOpen ↗