Racing in the heat

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. 



  • 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.
  • 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. 

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


  • 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.

  • literatinliteratin ✭✭✭

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

  • 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! image

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

  • literatinliteratin ✭✭✭

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

  • 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:








  • 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?

  • 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! image

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


  • 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.

  • literatinliteratin ✭✭✭

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

  • RicFRicF ✭✭✭

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


  • 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 !

  • 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.

  • literatinliteratin ✭✭✭

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

  • DT19DT19 ✭✭✭

    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 weekimage

  • RicFRicF ✭✭✭
    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.

  • There is a race I do. The Midsummer Munro at Box Hill, Dorking. They wont start the race till it drops below a certain temperature. A lot of it has to do with it being very steep climbs.

    I have done half's that were flat but have done them slower than hillier races, purely because of the heat. It makes sense your times will suffer.

  • I've been looking at the results of some of the local races over the last couple of weeks and comparing the times to previous years. My rigorous analysis seems to indicate that the quicker guys aren't noticeably affected but those further back in the pack are slower.
  • literatin wrote (see)

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

    Hmmmm...the shade was indeed very welcome, but felt like I blew up a bit over the last couple of miles, and the turn off the road to climb back up the forest track felt like it virtually stopped me dead.

    Having said that, I've found some of the shared activities on the Garmin Connect website that shows others (including 30:42 and 31:02 runners) had a comparable drop off between the 1st and 4th mile splits that I had, so perhaps that was more to do with the profile than specifically the way the heat got to me - approx 55 seconds difference between mile 1 and mile 4 for me! Did pick it up again a bit in the final mile, and finished as 88th bloke in about 34:08. Would have been comfortably good enough to points score for the Senior Men's side, but they're struggling for depth and are well down the rankings, so the captain slotted me in just behind him as second points scorer for the Vets 'B' Team. Hoped for a little more, but not the worst of debuts I s'pose.

    How about you? Were you in the mix at the front of the gals race again? Have you got split times?

    Did see you at the finish, but you seemed to be going through some very complicated stretching routines with a clubmate (Geoff?), so thought I'd leave you to it, got involved in conversation and then didn't spot you again after that.

    EDIT: How soon do the results tend to come out? Couple of days or so presumably?

  • literatinliteratin ✭✭✭

    I was 2nd lady. image I wouldn't worry about the splits, as the first mile was pelting down a steep hill on tarmac, and the 4th one was running uphill on a woodland trail so they were always going to be a bit different.

    EDIT: results: a few days, I expect.

  • Excellent..congrats!

    5th, 3rd and 2nd for you now then isn't it in the Summer League? So the progression surely means at Teversal...


  • literatinliteratin ✭✭✭

    Haha, I will win the whole thing if that happens. But likely to be more faster people as it's not so far away so there will be a better turnout in general.

  • You'd think that, but looking at the last couple of years, the Worksop run has actually had a bigger turnout than Teversal, though that in itself doesn't necessarily reflect the quality of runner that will turn up of course. 

  • literatinliteratin ✭✭✭

    Well, there's only one person I need to beat anyway and I'm pretty sure she'll be there. Sent you my splits in a PM.

  • Sorry - completely missed the PM. Used to get mail notification of them, but that's another 'improvement' they've made to the forum by the looks of it. image

    Looks like a tasty final race in store at Teversal!

  • HellywobsHellywobs ✭✭✭

    Maybe I'm just rubbish in the heat! My 10k PB is 46:30 and I've run 3 10ks this year ranging from 46:45ish to 48:15ish.  Yesterday I did the pancake flat Dorney Dash in, well, 51:40 which is even more rubbish when you consider I got to 5k in around 24:30!  And it was "only" about 21 degrees but it was pretty humid.  I've run two personal worsts on the club handicap race course since the hot weather started as well. The problem is the more bad races I have, the more I worry and the worse it gets.  I seem to be ok up to 5k as I did 23:30 at a parkrun last Sat, which was ok and very steady, and a bit over 27 mins at the 5.6k JP Morgan Challenge but the heat/humidity seems to be sapping my stamina.

  • RicFRicF ✭✭✭

    How much do you really drink? I'm still coming across runners whose entire days intake amounts to two or three cups of tea and then complain they're struggling to train.


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