warm weather hydration data
Donovan Rebbechi
weather running. The data are quite interesting, thought it would be worth
sharing.
Stats:
pre-run weigh-in: 149lb with reasonable hydration, BMI 20.x
temperature: warm -- low 80s. Somewhat muggy.
the run:
weigh-in (149.0)
9.7 miles at about 7:50,
weigh-in (145.4)
break for drink,
weigh-in (147.4)
7 miles at 8:00
weigh-in (144.0)
Water loss: 3.6lb in 77 min, 3.4lb in 56 min (about 1lb/20 minutes)
This is a somewhat faster rate than the "standard" 1kg/hr formula, despite the
fact that I am fairly thin and well acclimated. Larger or less acclimated
runners may lose more than this.
Note that with the one drink stop in the run, I'm still 5lb down. This is about
the max I can drop without it feeling pretty bad at the end of the run.
The bottom line, it makes me think Tony's idea of just lugging around a water
bottle is probably a pretty good idea for a lot of people. If I lost water any
faster, I'd probably need to find a way to take an extra 1-2lb of fluids during
the run (I find it pretty hard to take more than 2lb in one sitting)
Cheers,
--
Donovan Rebbechi
http://pegasus.rutgers.edu/~elflord/
Phil M.
> Recently, I've tried doing fairly careful pre and post-run weigh-ins for warm
> weather running. The data are quite interesting, thought it would be worth
> sharing.
>
> Stats:
>
> pre-run weigh-in: 149lb with reasonable hydration
I seem to recall you weighing ~165. Have you lost 15 pounds in the past
year? Maybe due in part to dropping the weight lifting from your
regimine?
> weigh-in (149.0)
> 9.7 miles at about 7:50,
> weigh-in (145.4)
> break for drink,
> weigh-in (147.4)
> 7 miles at 8:00
> weigh-in (144.0)
>
> Water loss: 3.6lb in 77 min, 3.4lb in 56 min (about 1lb/20 minutes)
>
> This is a somewhat faster rate than the "standard" 1kg/hr formula, despite the
> fact that I am fairly thin and well acclimated.
Like I mentioned in Dan's Bulldog thread, in 80+ temps it can be as
high as 5 lbs per hour, at least from what I've been reading. What were
your weather conditions? What exactly were you drinking? I'm thinking
absorption rates of different fluids may impact your results.
> Larger or less acclimated
> runners may lose more than this.
I gotta get smaller (sans drugs). ;-)
> The bottom line, it makes me think Tony's idea of just lugging around a water
> bottle is probably a pretty good idea for a lot of people. If I lost water any
> faster, I'd probably need to find a way to take an extra 1-2lb of fluids during
> the run (I find it pretty hard to take more than 2lb in one sitting)
I'm drinking about 36 to 40 oz of Cytomax per hour, but not at one
sitting. Usually 12 oz per 2 to 2.5 miles.
--
Phil M.
David Geesaman
> weigh-in (149.0)
> 9.7 miles at about 7:50,
> weigh-in (145.4)
> break for drink,
> weigh-in (147.4)
> 7 miles at 8:00
> weigh-in (144.0)
>
> Water loss: 3.6lb in 77 min, 3.4lb in 56 min (about 1lb/20 minutes)
Interesting indeed. Did you strip off clothing for the weigh-ins, or
just sock feet?
Dave
Donovan Rebbechi
> Interesting indeed. Did you strip off clothing for the weigh-ins, or
> just sock feet?
Usually I don't, but this time I needed to remove my singlet because it was
drenched.
Donovan Rebbechi
> Donovan Rebbechi wrote:
>
>> Recently, I've tried doing fairly careful pre and post-run weigh-ins for warm
>> weather running. The data are quite interesting, thought it would be worth
>> sharing.
>>
>> Stats:
>>
>> pre-run weigh-in: 149lb with reasonable hydration
>
> I seem to recall you weighing ~165. Have you lost 15 pounds in the past
> year? Maybe due in part to dropping the weight lifting from your
> regimine?
Dropping the weight lifting helped, but I was 160 just a few months back.
I dropped the last 10lb mostly by just watching my intake very carefully.
> Like I mentioned in Dan's Bulldog thread, in 80+ temps it can be as
> high as 5 lbs per hour, at least from what I've been reading. What were
> your weather conditions? What exactly were you drinking? I'm thinking
> absorption rates of different fluids may impact your results.
The drink was just ordinary diet soda.
Weather was low 80s and humid.
Ed Prochak
Donovan Rebbechi wrote:
> Recently, I've tried doing fairly careful pre and post-run weigh-ins for warm
> weather running. The data are quite interesting, thought it would be worth
> sharing.
>
> Stats:
>
> pre-run weigh-in: 149lb with reasonable hydration, BMI 20.x
> temperature: warm -- low 80s. Somewhat muggy.
>
> the run:
>
> weigh-in (149.0)
> 9.7 miles at about 7:50,
> weigh-in (145.4)
> break for drink,
> weigh-in (147.4)
> 7 miles at 8:00
> weigh-in (144.0)
>
> Water loss: 3.6lb in 77 min, 3.4lb in 56 min (about 1lb/20 minutes)
>
> This is a somewhat faster rate than the "standard" 1kg/hr formula, despite the
> fact that I am fairly thin and well acclimated. Larger or less acclimated
> runners may lose more than this.
the warm, humid weather certain can make it worse. Will you run this
experiment again in closer to ideal temperatures? Could be a good
experiment. (I have thrown some numbers on weight loss on the run in my
log, but maybe I'll try this too.
>
> Note that with the one drink stop in the run, I'm still 5lb down. This is about
> the max I can drop without it feeling pretty bad at the end of the run.
>
> The bottom line, it makes me think Tony's idea of just lugging around a water
> bottle is probably a pretty good idea for a lot of people. If I lost water any
> faster, I'd probably need to find a way to take an extra 1-2lb of fluids during
> the run (I find it pretty hard to take more than 2lb in one sitting)
yes a little now and then, spreading the water intake over time and
miles works better for me too. I know for a long time that seemed to be
my montra in this group (HYDRATE!), but it is a very important lesson.
Measure your water loss so you know how to manage it, rather than
guessing and getting into dehydration trouble.
>
> Cheers,
> --
> Donovan Rebbechi
> http://pegasus.rutgers.edu/~elflord/
Thanks for the report. Time to add some more data.
Enjoy the run,
ed
Donovan Rebbechi
> the warm, humid weather certain can make it worse. Will you run this
> experiment again in closer to ideal temperatures? Could be a good
It's a good idea -- I'll give it a shot when it cools down. I think the
water loss will be substantially less (close to half). I can get away with
*no* drink in a 2hr run if it's cool, so it's probably less than 2.5lb/hr.
Tony S.
news:slrndh62tj...@panix2.panix.com...
Interesting you lost that much (3 pounds per hour) in somewhat average
summer conditions. As you were running about 2:10, your risk was managable.
For longer stuff you really need a strategy, as your post demonstrates. This
is the reason many of us try to do long training on loop courses where we
can stops at our cars to refuel every hour or so. It's boring but it beats
lugging many liters on your back. (I lugged 4 liters (a very minimal amount
for temps that day of 80 to 91 with medium humidity) on my back for a 5 hour
trail run last weekend and it didn't ride that well the first 3 hours).
I find even for medium efforts (1:20 to 1:45), having a bottle along helps
keep things in balance for after the run, when my priority is to eat a
mini-meal rather than trying to play catch-up on hydration. This is one
thing I love when biking. I can carry 2 liters easily. For running I usually
drink 10oz right before the run, then carry a 20oz bottle, which I hand
carry until it's 1/2 empty, then I put it in the waist pack.
This weekend I've got a ~7 hour run/hike scheduled in preparation for
Vermont. The dilemma is not only what course to run, but how to manage
hydration (and nutrition). While my strong desire is to do a long wilderness
loop to make it both enjoyable and easier to stay motivated, I have to have
*sure* water sources on such a run, or carry it all - a daunting prospect.
The alternative is to do local loops where I can hydrate well and also do a
variety of loops. But it's much harder to stay motivated doing 8 loops or
whatever than when doing a real long trail run. The former feels like work,
the latter an adventure.
-Tony
Doug Freese
If nothing else it gives you a perspective of what Dan, Tony, Phil and I
have to contend with when running ultras. This is one of the reasons
that we are so concerned with salt, dehydration and hyponatremia. Some
hundreds are so health concerned that they weight you during the race
and if you hit 7% weight loss your ass is out of the race. 5-6% and you
get a mandatory seat close to the aid table.
-DougF
Phil M.
> If nothing else it gives you a perspective of what Dan, Tony, Phil and I
> have to contend with when running ultras.
Wait just a sec, don't group me with that bunch of goofs. I haven't run an
ultra yet. ;-) Although running 20 miles in the Atlanta heat/humidity can
sometimes be ultra nutty (wife's term).
--
Phil M.
Phil M.
> I find even for medium efforts (1:20 to 1:45), having a bottle along
> helps keep things in balance for after the run, when my priority is to
> eat a mini-meal rather than trying to play catch-up on hydration.
Good point. Sometimes when I get back from a long hot one I'm fammished and
I really feel like having some solid food. But if I'm dehydrated also that
has to take priority. In that case, I'll break out the smoothie machine and
dump a bunch of calories into the mix.
> This weekend I've got a ~7 hour run/hike scheduled in preparation for
> Vermont. The dilemma is not only what course to run, but how to manage
> hydration (and nutrition). While my strong desire is to do a long
> wilderness loop to make it both enjoyable and easier to stay
> motivated, I have to have *sure* water sources on such a run, or carry
> it all - a daunting prospect.
Sounds like you need a crew. I'll be there, just pay for my travel
expenses. ;-)
--
Phil M.
Sam
hour. 1L=1kg for practical purposes.
So you are at about 1.5 l/hr--pretty normal.
"Donovan Rebbechi" <ab...@aol.com> wrote in message
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