Racing in the heat

How much pace per mile do you give up to it?

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17/07/2013 at 09:52

I'm after a spot of advice.

I only started running in November, so the current hot conditions are rather alien to me in terms of just getting out of the door for an easy run, never mind racing.

I've got a 5 miler tonight, and it's forecast to be 27C, possibly even warmer at the race start time. I had another 5 mile race about a fortnight ago when it was 22C and I found that very oppressive, but got myself round in 33:34, or around 6:42 pace.

I can tell from a 7 miler on Friday night, and a shorter run with a bit of pace thrown in last night, however, that 22C to 27C (or more) is another big step up in terms of the effect that the heat has on your body and its ability to run, particularly at pace.

Although I know each individual will be affected slightly differently, I'm therefore interested to know how much pace others would plan on giving up to the conditions compared to racing in milder weather? Should the previous 6:42 pace be more like 6:50, or even 7:00? I've really no idea.

It's my first race for a club I've just joined, so whilst I'm concerned about going off too hard and blowing up in spectacular fashion, I'm also keen to give it my best shot. 

cougie    pirate
17/07/2013 at 09:59
It really depends on you. Skinnier people should cope with the heat better than well upholstered people. I really dont think there is any hard and fast rule. Apparently it helps if you're cooler before you race - so take along a slushie type drink and sit in the car with the aircon on until its time.
17/07/2013 at 10:21

College Pines is not too hilly with some shade in the woods Bob. You might just be okay for 5 miles. Wouldn't want to go any further than that. Remeber that it's all about positions so it's the same effrect for everyone. 

17/07/2013 at 10:22

Maybe you could take your watch off and just run to how you feel. 


17/07/2013 at 10:30

Thanks, Cougie. I'm certainly skinnier than I was this time last year, as an overweight, lazy sort, so that's encouraging. I'm going straight from work, but have brought a cool bag and several bottles to take water with me - I might put the smaller bottle in the freezer mid-afternoon then, to try to get it iced up a bit before I head off.

Funnily enough, I'd also thought about the air-con option in the car. Was planning on getting my warm up done in time to go and sit back in there for 5-10 minutes with that blowing at me full blast before the race.

Sussex - Indeed. I'd read about the shade - small mercies and all that! You're right about it being for positions of course. And that's an interesting thought, but I'm not sure I'd trust myself without the watch. My inexperience means I'm inclined to go off far too hard, so I use my watch to moderate my pace to something a bit more sensible over the first mile.

Thanks both.

17/07/2013 at 10:39

It's only 4.9 miles anyway. It'll be EASY.

17/07/2013 at 11:13

Taking into account both response and appearance, I shall remind you of that comment, and see if you still feel the same after the race, Lit! 

(Assuming you're not half way back to Nottingham by the time I wheeze in.)

17/07/2013 at 11:22

You won't be able to find me. I'll have melted.

17/07/2013 at 11:24

17/07/2013 at 11:44

Someone posted this (appropriately) on Cool Running:

Galloway's Book on Running (1984) has a chart called "Adjusting race pace for heat".

Estimated temperature at finish...Slower than goal pace
55-60 degrees.....1%
60-65 degrees.....3%
65-70 degrees.....5%
70-75 degrees.....7%
75-80 degrees.....12%
80-85 degrees.....20%
above 85.....forget it, run for fun


Converting to proper units this would be:








17/07/2013 at 13:04

Tom, I imagine that's for people accustomed to a temperate climate like ours? I would have thought those who live in and are therefore acclimatised to sub/ tropical temperatures would do better?

Does the book (Galloway's Book on Running) make for good reading?

17/07/2013 at 13:07

Thanks, Tom. Interesting - looks a bit pessimistic from Galloway though perhaps?

Would predict an approximate 5% deterioration in performance from my 33:34 at 22C, giving me around 35:15 tonight. Hope I can do a little better than that.

What I do like however, though find even less likely, is the 7% he's giving me on the 33:34 had it been run at, say, 10C, predicting me to be in 31:20 shape over 5 my dreams! 

I wonder whether his scale is more applicable to longer distances?


Edited: 17/07/2013 at 13:08
17/07/2013 at 13:51

I haven't read Galloway's Book on Running, if it came out in 1984 it might be out of print. I read his Half Marathon: You Can Do It book when I was training for my first half, found that useful as it's mostly aimed at beginners.

According to this, ideal temperature is lower for longer distances:

 So I think the heat will affect you more the longer the distance you run.

17/07/2013 at 14:07

Excellent link, Tom - looks like women's optimum temperature for racing 10k goes up to almost 80F. Pleasing.

17/07/2013 at 14:50

All my fastest times up to and including the HM were set in heat of at least 80F or 26.5C.


17/07/2013 at 21:17

Humidity is probably worse than heat. People who sweat heavy have good cooling systems but need to replace the lost fluids over a distance. Longer distance races have more factors of dehydration than shorter ones and the heat has a big psychological effect. You think you are beat, then you already are !

Edited: 17/07/2013 at 21:17
17/07/2013 at 21:43

Mcmillans heat adjustment calculator is based on temperature and humidity.  I am too tight to pay for Mcmillan Pro, and in any case my own statistical research shows I am absymal in the heat.

17/07/2013 at 22:39

Update: was fine actually. Lots of shade in the woods like Sussex Runner said. How did you do, Bob?

17/07/2013 at 23:14

Those time drops offs from Galloways book seem extremely generous. Even in a marathon situation I cant see a 4hr runner  in 25c being able to run 3hr 30 in 20c. I'd like to believe them however as it would mean I have been catapulted to a 38 min 10k runner based on my two 10ks last week

18/07/2013 at 02:28
Sussex Runner (NLR) wrote (see)

Humidity is probably worse than heat. People who sweat heavy have good cooling systems but need to replace the lost fluids over a distance. Longer distance races have more factors of dehydration than shorter ones and the heat has a big psychological effect. You think you are beat, then you already are !

Totally agree with this SR.

For that reason I drink at the start 100ml for every mile to race. I don't drink during the race but pour the water on my head instead.

The drop off times mentioned are aimed at beginners and average runners. The result of not having a clue of how to race in hot conditions.

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