Anybody see any charts regarding performance loss in relation to heat index?
No, actually, I haven’t seen anything like that. This is way outside my knowledge base, but a very quick search of the lit shows most papers are concerned with hydration, so it seems that the effects studied are more indirect than what you are looking for. I did find one review regarding nutrition in the heat which might or might not help. If you want it, PM me your email.
I know there is some research on how a body handles heat and why lighter, shorter runners usually do better in the heat. Send me a PM tomorrow and I’ll look things up. I have too much work tonight.
Race lately? And why not?! Excuses, excuses. 
I swear I saw a table in Noakes’ book, but can’t find it now. Will let you know if I find it.
Physiological Bases of Sport Performance Chapter 10.
Might not be quite what your looking for… but some interesting stuff.
I think I did read something, a while back, called the “Wuss-a-fication index”.
get riding nancy boy
I know that I never run well when the barometric pressure is low, so if anyone digs up any literature that explains why I’d love to see it.
How about moon phases? Any data on that? I know I always seem to be slower during a full moon. Maybe it’s all the extra hair.
never been one to check the barometer before i head out, so i don’t have a clue how that affects me. but an extremely non-scientific guesstimate is that as the heat goes up the heart rate will follow, given the same intensity during the workout. i was thinking about this as i completed the run portion of a brick wednesday here in the tropical heat of the south. the heat index was around 110. my heart rate was at least 10 beats higher than it normally would be. i was well hydrated by the way.
Good question if you get any results…please post.
my coach published an article here on slowtwitch, called something like “Thermoregulation.” it was a goody: the guy’s a champ athlete and a PhD in environmental physiology. i think it’s under the “training” tab off the main page.
-mike
I wouldn’t expect to see charts - altitude tends to affect everyone similarly, heat effects are much more individual. As Brian noted, lighter shorter runners tend to be less affected. The physiological reason IIRC is that they have a better surface area/weight ratio, which translates into better cooling. But it’s still very individual - an interview with Meb Keflezighi in this month’s RW notes that Stefano Baldini is known as a good hot-weather runner, so was expected to be a threat at Athens. He’s 5’9", big for a marathoner never mind a hot-weather one.
Also interesting, the womens’ Athens results,
- Noguchi 4’11" 88lbs
- Ndereba 5’3" 99lbs
- Kastor 5’4" 104lbs
and the unfortunate Paula Radcliffe, 5’8" and 117lbs. I don’t think she ever had a chance in that heat…
If you have a copy of Daniels book on page 191, Table 10.1 shows the effect of heat on running performance…
Race duration of 2:10 in good conditions will typically take +2minutes in 70 degree weather, and +8 minutes more in 100 degree weather.
Race duration of 4:00 in good conditions will typically take +4minutes in 70 degree weather, and +17.5minutes more in 100 degree weather.
The table has many more temperatures and run durations listed, I just noted the lowest listed and the highest listed. I don’t have the literature at my side, but this table is similar to many of the tables listed in my many different physiology of exercise books that i use in school. My educated guess is that the effect on running in a tri would be even more profound as we are baking in the sun for who knows how long before we start running. I hope this helps a little bit.
Daniels, Jack. *Daniels Running Formula. *pg. 191. Human Kinetics Publishing, Champaign, IL. (1998) – Not sure what is needed to site someone elses work on this site, so here this is just in case…
Air density is lower; similar to moving to higher altitude.