Running in the heat - any benefits?

Now the summer is arriving, I'll be indulging in an old habit: going for my weekend runs at the hottest part of the day. 

Mrs samoff thinks I'm daft, but I honestly love it and as long as I'm careful with hats and drinks and sunscreen I can see no harm in it. It's hardly the serengeti after all.

My question is can I point to any actual benefits of running in, say, 20C compared to 12C? I'm hoping someone will tell me I'm less liable to injury or more likely to burn the right sort of sugars, or some such nutritional detail.  

Go ahead, make my (sunny) day.


  • Three things come to mind:

    1. Burning more calories: theconsensus is against the myth you sometimes see that sweating a lot is causative in burning more calories. (Maybe this stems from boxers trying to get under a weight limit by traning in a sweatsuit, when in fact this simply causes loss of liquid, which is made up later.)
    2. Protection against injury: Warm muscles and ligaments cf. cold might help avoid injuries a bit.
    3. Heat acclimatization: If you're planning in a race where it is warm then training in the warm a couple of weeks before will help. Some folks in extreme heat races even do some acclimatization in the sauna.


  • Samoff , why not ?? Running in sunshine is great as long as you're sensibleimage I'm with SteveC , I ran a lot last summer in the heat to acclimatise for the Majorca Marathon including the 2 weeks holiday in Puerto Rico , it helped me get my fluid intake right , just as well because it was bloody melting in Majorca image

  • RicFRicF ✭✭✭

    Paul Tergat recommended training in the hottest part of the day.

    Keep fully hydrated with the sun-block in place and there's advantages to be gained.

    The heat will increase the blood flow to the skin so the volume needs  to be kept up to supply the muscles. So a gut full of water is required. The overall result will be a larger blood volume.

    The first race on a cold day will see the results. Less blood to the skin means more to the muscles, so less fatigue.

    That's really what warm weather training is about. Not just about getting used to heat.

  • Hmm.  Far be it from me to get in the ring with Paul Tergat, but I did all my training for the Chester marathon 2012 while living in West Africa.  I don't think it made a lot of difference, except that many runs were inevitably harder/slower than they would have been in the UK.  My race time was more or less what I'd have expected if I'd done the exact same training in cooler conditions.  

    I don't think it's like training at altitude, where you really do get physiological adaptations that last for weeks and improve overall performance.  The blood volume thing seems wrong to me as it's totally short term, i.e. it's a temporary adaptation that helps you deal with the conditions you're running in.  As soon as you've sweated or pissed out the extra fluid your blood volume goes back to what it always was.

    Basically, running in extreme heat and humidity is good for one thing, which is acclimating to extreme heat and humidity.  Oh, and learning the best way of cleaning out a Camelbak after putting isotonic powders in the water.

  • A question related to the original post. Where I live (4000 ft of elevation) summer temps are regularly in the 90 to 100 degrees F range. This puts the air density altitude above 7000 ft. Wouldn't running at temps in this range be the same as running at 7000 ft. and cooler temps. I know this effects airplanes and drag racers why not people? Just for kicks put in the current temp of 103 and barometric pressure, and got a density altitude of 8000 ft

  • samoffsamoff ✭✭✭

    Hoo. I seem to have started a healthy debate, which is always gratifying. 

    I'm not sure about your barametric thing jsal. Wouldn't humidity come into play if we talked about air density?

    Martin: I tried to make it clear in my original post that I already run in hot conditions and that I enjoy it. Unfortunately I'm not acclimatising to anything as I can't afford to go anywhere warm.


  • NayanNayan ✭✭✭

    Use sunblock and a hat

  • samoff wrote (see)

    Martin: I tried to make it clear in my original post that I already run in hot conditions and that I enjoy it. Unfortunately I'm not acclimatising to anything as I can't afford to go anywhere warm.


    Don't worry, the warm weather's coming to us:

    So you will be ahead of the game once +2C kicks in, and all the rest of us are panting and sweating.  Unless you live in Norfolk, in which case taking up swimming might be a better move.

  • samoff: Was using a density altitude calculator with inputs of  elevation, air temperature, barometric pressure (adjusted for altitude) and dew point.  Never really thought about the effect of humidity as we have none here (currently at 6%). When I changed the dew point from it's currrent 29 degrees F to 80 degrees F the density altitude went from 8100 to 8500 feet! Don't think I would run in that.

  • MuttleyMuttley ✭✭✭

    You need reasons to go running in warm sunshine rather than freezing cold and pissing rain? image

  • +1 what Muttley said....

    I did a marathon last weekend - no shade - c20 degrees.  I wore a light-coloured cap and kept filling it with water to keep my head cool.  The rest of the time I took on water and gels as normal.

  • samoffsamoff ✭✭✭

    Ho hum. I thought it was obvious that I wasn't complaining about the heat and that actually I really enjoy it. 

    Never mind.


  • I for one envy you Samoff  -  I detest running in heat and can think of nothing nicer (truly) than a decent downpour or, failing that, a nice bit of drizzle.  My best HM time was achieved in a vest and shorts when my OH was going blue in his thermals, gloves and bobble hat.

    He's getting his own back at the moment though  image  You enjoy it while it lasts and he reckons that he injures himself much less frequently as long as he hydrates properly. No scientific backup, just personal observation!

  • You get used to running in the heat, it's over 40 during the day here but a run in say 35 degrees feels comfortable. As for rain, we had some in March! 


  • Do what I did this lunch time in our sunny bit of London: apply sun cream liberally, grab a bottle of water, and enjoy image

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