[email protected] wrote:
> it's common knowledge that running in cold weather
> is easier.
Hmmm. If this is so, why do many people on r.r complain
about the cold and/or run on treadmills when it's "cold",
whatever that means? Ok, they also complain about the heat
and/or run on treadmills then.
>why exactly is this? i know you sweat less, and the air
>probably has more oxygen, but is there more to it?
Since I'm not sure what you mean by "cold" nor "easier" nor
what you are comparing it to, I'll take usenet license and
interpret in a broad sense
- actually two senses
The "easy" itself will refer to (1)
number of hassles and (2) pace. I'll assume "easier"
refers to a comparison with "warmer" weather
[If you're only interested in the +40F to +80F range or
something near that, then skip to end - BUT you didn't
indicate that in question
]
I'd suggest that the easiest running is at some optimal
temperature - neither hot nor cold - that probably depends
on each person and their training as well as heat/cold
adaptation at the time. As things get colder or hotter from
there, pace (assuming decent footing - that is, not snow/ice
or sand dunes) will probably get slower.
Based on what people here seem to think of as ideal
temperatures for a marathon (based on race reports), I'm
guessing for many (not all) people the optimum temperature
may be near 40F/5C (plus or minus a few degrees), esp. if
overcast. It's also about half way between some of the
extreme temperatures I've seen for races. I think Badwater
gets up around 120F/60C (maybe 130F and road temperatures
much higher). Fairbanks has races at -40F/-40C, maybe
colder, and the Iditarod Invitational currently in progress
has temperatures at least that low. Guess where the midpoint
between those extremes are, approximately.
Hassles:
1. Fluids Hot - need lots of water and electrolytes to
reduce chance of heat injuries - discussed here
frequently. Keeping fluids at a palatable temperature
might be an issue. Cold - also need water to reduce
chance of cold injuries (hypothermia, frostbite), but
fluids are likely to freeze unless you master the
equipment and techniques for keeping your fluid fluid at
-20F. You may not sweat as much (unless overdressed), but
you'll be losing moisture through respiration. Cold air
(+10F/-12C and colder) tends to be dry. (I don't have
quantities or temperature relations on how much is lost,
but it is something I'm looking for literature on.)
Somewhere in between, you just need *some* fluid and it's
not going to freeze on you and will be palatable.
2. Clothing Hot - some go minimal, some dress to minimize
skin exposure, but some degeree of concern is needed.
Cold - lots of issues as to how to layer to keep warm but
not sweat. Discussed here frequently.
Somewhere in between, you just need one layer without a lot
of thought for what to wear.
3. Muscle/tendon function Hot - action will probably be more
fluid than in cold temperatures unless overheated. Cold -
muscles, even when running for 1/2 hr or more, may not be
as internally warm at -20F as at +80F. (Not sure if this
is generally true or not, but for me last summer when
doing some hill work in +80+F temperatures, my achilles
was far more flexible than it ever gets in the winter.)
Somewhere in between, there may be optimal function without
overheating.
4. Metabolism. I've seen some secondary literature
suggesting that metabolism in cold temperatures may use
more fats. (looking for primary literature on it as well
as some other cold weather physiology issues relevant to
running in the cold (cold being subzero F))
5. Eyes - need to protect from bright sun and/or cold
temperatures. Not sure I've heard of anything about heat
injury to eyes, other than sun related.
6. Equipment damage - extreme heat like Badwater can cause
some shoes to fall apart.
Cold/heat adaptation in humans is a few dissertations.
Pace: You might look at Running Club North in Fairbanks.
http://www.runningclubnorth.org/rcn_4res.htm They record
weather for many of their race results, and Fairbanks (as
well as many interior US/Canada areas) has temperatures from
-40F to 90F, maybe higher. Many of the Fbks races involve
trails and/or hills and/or snowshoes so you'd have to pick
which ones to look at. You might also look at some of Lorne
Sundby's race reports, but might need to pay attention to
windchill vs temperature on his. iirc, he had consecutive
races at the two extremes - I'm thinking it was in spring
2002 (maybe 2003). In one of his posts back then, he also
gave an indication of how much faster he got as the weather
warmed. I'd look, except I don't need the numbers to know
that paces get faster, and it's much easier running in
warmer weather - at least where I am
My actual numbers
are confounded by snow, dark, snowshoes, hills, and amount
of training in summer vs winter.
If nothing else, when reducing the number of layers being
worn, it will reduce the dead weight you are carrying as
move from cold (0F and below) to warmer temperatures (20F
and above).
But if you're just talking about pace somewhere around 80F
vs 40F, then it's probably primarily a cooling mechanism.
When you start dealing with temperatures like +120F vs -40F,
the amount of oxygen in a volume of air may have an effect
perhaps equal to a few thousand feet elevation change (check
the formulas I posted the other day). But at 80F vs 40F I
doubt that it's significant.
Dot +30F is much easier (workload) than -20F because of
fewer layers and no showshoes. That's *my* common
knowledge
--
"Success is different things to different people" -Bernd
Heinrich in Racing the Antelope