| Author |
Topic: Running in the Heat |
SkipAZ
Cool Runner |
 posted Jun-26-2007 12:11 PM
  
Hey All,A number of comments in the daily about dealing with the heat. I thought we should try to gather some of the collective wisdom in one place. (Maybe eventually move it to the Wiki, eh Sally?) So here's my suggestion: Dial back your expections. You're just not able to run as effectively in hot whether. One reason for this is your body diverts blood flow from the exercising muscles to the skin for cooling. So how much of an effect? Here's a graph I put together when we had this discussion here in CR almost exactly two years ago:  As I recall, the Tinman data is the work of Dr. Jack Daniels done on mostly elite distance runners - solid scientific data on the cream of the crop. Glover (NYRRA coach) provides a thumbrule for the rest of us more average sorts. Neither specifically address the effect of humidity but if you use "Real Feel" temps vice just what the thermometer reads, I think you can factor it in. So what does the graph mean? Let's say you ran a PR in early April and the temp was 55-60F. All other things equal but today the temp is 90F. On the same steller effort today would see about a 10% loss in performance so your 22 min 5K PR fitness level would only get you ~24:12 minutes today. This is nominal - individually you may be more or less affected than the curves suggest. Take away: Dial back your expectations in the heat/humidity. This applies to training paces as well as racing. I hope others will add to this thread with tips/questions and answers about running in the heat & humidity. Be safe out there friends. Skip
[This message has been edited by SkipAZ (edited Jun-26-2007).]
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Canfit
Cool Runner |
posted Jun-26-2007 12:27 PM
mcsolar replied to a question I posted in the daily thread yesterday which offered some good advice on this topic.
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Interesting how the heart rate moves up despite slow pace, due to heat. When your HR is high like that, does that mean it doesn't count as an "easy" run?
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the best thing about running in the heat is that i have to slow way way down. this means that my legs don't get as much of a workout, but my aerobic system gets worked. it almost seems like cross-training to me at times.still, if you really want an "easy" workout in the heat, you need to slow down and go with an easy heart rate. this is important if you've got a race coming up or another tough aerobic workout (long tempo or long run) soon.
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enkephalin
Cool Runner |
posted Jun-26-2007 12:35 PM
SkipAZ, Thanks so much for posting that graph! I was just today going to ask the board if they could find some real data on it.Time to start dialing back my expectations for my next race.
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TheProFromDover
Cool Runner |
posted Jun-26-2007 12:37 PM
Just as an aside. I love heat. Because it affects other runners more than me. So sure, my time is slower, but I am higher in the rankings. Let's hope for 90's for the Corporate Challenge in Boston on Thursday.Best of luck tonight Skip!!
-cAIgt
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Tramps
Cool Runner |
posted Jun-26-2007 12:44 PM
Just as an aside. I hate heat. Because it affects me more than other runners. So my time is slower and I am lower in the rankings.
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Spareribs
Cool Runner |
posted Jun-26-2007 01:09 PM
In one of his books, Bill Rodgers advised that if you are training, to do it early in the morning or indoors to find some way to get out of the heat. He doesn't feel you can train properly in the heat. I had always maintained that running strong all through the TX summer heat put me in good shape for the fall races when temps were cooler. So I asked him about this. His point was that you can't do good quality work in the heat (which is true) and he acknowledged that good base work and slow miles were indeed a good idea in the heat, but if you want to get the most from your quality workouts, heat is an impediment to top performance. I now understand his point.Lydiard had a most bizarre point of view about the effect of humidity, and you may recall that Ted Andresson asked about this some time ago. Ted is a scientist about everything and I directed him to Lydiard's book, since I didn't want to write the entire page on CR, but I never heard back about what he learned. I try to work hard the first 3-4 weeks of our hot season here in order to get used to the heat, but beyond that I don't have high expectations for racing. For a fiveK, I am in about 6:45/mile fitness, which I did this spring. My last two races have been 7:09 pace for tenK and 7:01 pace for a fiveK, and I am probably fitter now than when I was running 6:45's. I am not concerned about it, as I have no big races schedule for the summer in Texas. It is good you posted this Skip. A couple of years ago I used to fine people for complaining about the heat, as if they were the only ones who had to run in it. Spareribs
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tomwhite
Cool Runner |
posted Jun-26-2007 01:28 PM
......oh, Shoot//...........Tramps just stole my Excuse....
.............hey skip//.............got any Heat Rash Tips??
[This message has been edited by tomwhite (edited Jun-26-2007).]
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Dark Horse
Cool Runner |
posted Jun-26-2007 01:47 PM
quote:
Originally posted by SkipAZ:
So what does the graph mean? Let's say you ran a PR in early April and the temp was 55-60F. All other things equal but today the temp is 90F. On the same steller effort today would see about a 10% loss in performance so your 22 min 5K PR fitness level would only get you ~24:12 minutes today. This is nominal - individually you may be more or less affected than the curves suggest.
I don't think a change in temp like that would cost me 2:12 in a 5K, or anything close to 2:12. When I ran a 5K in August in humid 90+ temps, my time was 21:10. When I ran another 5K in September in humid 60 degree temps, my time was 20:26. My time in the cooler race was 44 seconds faster, but it was also a much flatter course, which explains much of the difference. That said, one of the leaders in my August race, when it was 90+, collapsed a couple hundred yards short of the finish line and had to be treated by medical personnel. I think he was on pace to run 15:XX. I know him, and I doubt he would have collapsed in cool temperatures. I guess he was working harder than I was. Dark Horse ------------------
I'm a dark horse, running on a dark race course
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mcsolar99
Cool Runner |
posted Jun-26-2007 03:05 PM
hey skip, great timing. i've been wanting to look at this more quantitatively. could you post the numerical values for that chart? just looking at say the decrease in partial pressure of O2 with temperature (nkT) seems to provide a nice fit to the first part of tinman's data. after 90f and below 60f there must be thermal regulation issues... i wonder how that's been quantified?ok, so i eyeballed the values off the graph. as the atmosphere heats up, the number of oxygen molecules in a given volume decreases. so, the number of molecules in tinman's lungs decreases as the temperature of the air increases (just like at altitude). if we use the perfect gas law, and convert temperatures to kelvin, then the percentage of o2 at temperature t compared to at temperature 60f (= 289K) is simply given by the ratio of the temperatures 289/t. at 100f (= 311K) there are only 93% as many oxygen molecules in a given volume than in the same volume at 60f. (all of this assumes constant pressure; apparently this varies too, but it's a much smaller effect, less than 0.5% from 60-80f http://www.noaa.gov/questions/question_121902.html) you'd expect that the amount of aerobic work he could do would also decrease, since that's directly related to the amount of oxygen he can supply to his muscles. so the dashed line is simply the decrease in the o2 number density in his lungs, and it provides a great fit to the measured performance drop across the 60-100f range.  this completely neglects any heat transport effects... i.e. does he become less efficient at higher temps. you can see that these effects likely come into play at 110f, where his performance drops below the o2 density drop. the drop at cold temperatures must be something else too. [This message has been edited by mcsolar99 (edited Jun-26-2007).]
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Karl Rysted
Cool Runner |
posted Jun-26-2007 03:09 PM
Great thread! Hopefully any newbies who haven't trained in the heat yet can avoid problems.If you've read any of my posts in the daily, you know how up and down the Oklahoma weather has been so far this summer. It's unusally wet, and I'm thanking my lucky stars but will use the treadmill as necessary for now. Luckily I don't plan to run fast after the Missoula Half next month. I'll be doing my first trail marathon in August, Haulin' Aspen, and while the temps in Bend, Oregon shouldn't be a problem, the training here I would normally do for a PR would be. This will be the first year I've entered a race in July or August. So I'm considering dropping speedwork after Missoula. Haulin' Aspen is supposed to be very difficult anyway because of the huge elevation changes, so I think a PR is out of the question. Sorry for rambling but thanks for listening. As always, I'm open to suggestions. ------------------
My Profile
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Ileneforward
Cool Runner |
posted Jun-26-2007 05:27 PM
I don't think heat affects me like the way that curve on the graph looks. When I am running it feels like the heat doesn't affect me at all until it gets about 85 degrees and then I am affected by it.
Maybe women regulate their body heat differently? Is this chart based on data about male runners only? 
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Econo
Cool Runner |
posted Jun-26-2007 05:51 PM
Speak for yerself, Ileney!  This dewy Portland rose wilts in the heat. Salt, please!
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euphoric
Cool Runner |
posted Jun-26-2007 06:08 PM
I'm in the Ilene camp. That is, if she'll let me in.
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egrd
Cool Runner |
posted Jun-26-2007 06:11 PM
Econo, every summer, my DH installs a salt lick in our backyard.
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FlyingFinn
Cool Runner |
posted Jun-26-2007 06:12 PM
I'd rather run at minus 10 than 80. Running through sprinklers would feel good, if I could just get the neighborhood to turn them all on for my run.
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Soundrunner1012
Cool Runner |
posted Jun-26-2007 06:40 PM
I blow your theory too, Ilene. Anything over 60 I consider a hot day for running. I'm in a singlet at 45 degrees. Shorts at 35. I much prefer the cold and rain.I went out around 1:30 today and melted. 80 degrees. Turned around at mile 1.5 with the shakes and dizzies. Could've been the fact that I was starving when I headed out, I suppose . . . Where's my 6th grade whiz kid when I need him? I can't read charts. "Dial back my expections." That, I get.
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RunsTheBitterroot
Cool Runner |
posted Jun-26-2007 06:47 PM
Thanks for the info Skip. I think that graph reflects how I feel at the different tempuratures. I am kind of wondering how, pavement, direct sunlight, wind and humidity figures in there. I have noticed direct sunlight and slight tail wind seems to effect me most. Tim Noakes in his book Lore of Running has some good info on aclimitizing in the heat. I guess if you are going to run a race in the heat then some of the training should be in the heat. Larry------------------
"If you see a man running up a mountain trail in Montana with a fly pole attached to his back, you are probably lost. LDD
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choover
Cool Runner |
posted Jun-26-2007 07:39 PM
Interesting, Skip, except I think my death spiral begins at lower temps than your graph shows.I agree with FF in that I'd rather run at -10 than 80. I think our
Southern California girl Ilene is just much better acclimated to warm temps than those of us with more seasonal temperature swings. Seems like I just start to get used to warmer temps and then the mornings grow chilly again. This would be great to include on the wiki.
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Dark Horse
Cool Runner |
posted Jun-26-2007 07:55 PM
I don't know for sure that heat bothers me less than most people, but it may be true--at least for 5K and below.The insignificant change in my 5K times--when adjusted for course--is one data point. On an anecdotal level, when the Newburyport, Massachusetts temperature climbs toward 100 degrees, almost no one shows up for the Thursday cross-country race at the park at 5 p.m. The rolling field of tall grass is an empty wasteland of shimmering heat. But I always show up, saying, "What's the big deal?" Of course, this may just indicate I am more reckless than other people. Dark Horse ------------------
I'm a dark horse, running on a dark race course
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hally
Moderator of Boomers and Beyond |
posted Jun-26-2007 08:32 PM
Ilene, the insulation theory doesn't work either.I've got plenty of it. I would rather be in 25 then 75. I don't even need gloves after I've been moving for about 10 minutes.
Shade does help immensely though, don't know if that's mental.
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cajohnson5
Cool Runner |
posted Jun-26-2007 11:41 PM
quote:
Originally posted by choover:
Interesting, Skip, except I think my death spiral begins at lower temps than your graph shows.I agree with FF in that I'd rather run at -10 than 80. I think our
Southern California girl Ilene is just much better acclimated to warm temps than those of us with more seasonal temperature swings. Seems like I just start to get used to warmer temps and then the mornings grow chilly again. This would be great to include on the wiki.
As long as we are wishing, I would rather run at 50 than either of those temps...
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euphoric
Cool Runner |
posted Jun-27-2007 05:44 AM
I don't know if this makes any difference, but we don't have air conditioning. Maybe that helps with Camp Ilene? It was 80 degrees inside our home by yesterday late afternoon, and I was not uncomfortable. The dew point is in the 60s. Only looked at the temp because of this topic. I spend very little time in air conditioned environments, including the car. Maybe the ratio of time spent in air conditioning to actual temps has an impact on acclimation? Also, I don't train at the level many of you do. I'm sure intensity of effort also plays into the effect of heat and humidity.
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Ileneforward
Cool Runner |
posted Jun-27-2007 10:29 AM
I think my camp mate euphoric is on to something. I also don't have air conditioning, and I live in a pretty warm year round climate.
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