Running in the heat
Discussion
I’ve been back running since October, always on the treadmill in the gym until April when I switched to outdoors.
I’ve posted on here before about my running that tracks V02 max as an indication of fitness - I know many don’t think it’s a good measure to go by, but for me I think more or less it’s a vaguely good gauge of how I’m doing.
Obviously it’s been very hot for several weeks, so I’m hoping I’m right in thinking that your heart has to work a lot harder to keep you cool while running, which is why recently the app has indicated declining fitness.
Back in April I was “fairly” easily running 24 mins 5ks, but recently it’s been a real slog to hit the 25 mins mark.
The last couple of runs I’ve dropped my pace and run further, but the app has again said my fitness is declining.
Is the heat just messing everything up in terms of how far/fast I’m able to run and also what the app thinks my heart rate etc is doing?
I’m hoping that by just carrying on with the running, come cooler temps in autumn I’m going to see a pretty nice improvement in what I can manage
I’ve posted on here before about my running that tracks V02 max as an indication of fitness - I know many don’t think it’s a good measure to go by, but for me I think more or less it’s a vaguely good gauge of how I’m doing.
Obviously it’s been very hot for several weeks, so I’m hoping I’m right in thinking that your heart has to work a lot harder to keep you cool while running, which is why recently the app has indicated declining fitness.
Back in April I was “fairly” easily running 24 mins 5ks, but recently it’s been a real slog to hit the 25 mins mark.
The last couple of runs I’ve dropped my pace and run further, but the app has again said my fitness is declining.
Is the heat just messing everything up in terms of how far/fast I’m able to run and also what the app thinks my heart rate etc is doing?
I’m hoping that by just carrying on with the running, come cooler temps in autumn I’m going to see a pretty nice improvement in what I can manage
You divert a massive proportion of your blood volume to skin for cooling. This leaves less of your circulating volume taking fuel and oxygen to muscles.
All your device knows is that you have gone more slowly at the same or higher average HR
Hence it thinks you are less fit.
If you're really keen on monitoring VO2 max, you are better off scheduling a regular (say six weekly) rested max effort run in ideal conditions. If there is an improvement, it should record this as the new VO2max.
ETA my Garmin will 'hold' the new VO2 max for quite a while. By all means train VO2 max but there's really no need to fuss about it or test it week to week. It's a difficult metric to shift unless you're really unfit to start with. Training VO2max is like trying to make an engine increase capacity/power by repeatedly revving it to the limiter. For me, my 5-10% shifts in body mass have more of an impact on the figure than my absolute output.
All your device knows is that you have gone more slowly at the same or higher average HR
Hence it thinks you are less fit.
If you're really keen on monitoring VO2 max, you are better off scheduling a regular (say six weekly) rested max effort run in ideal conditions. If there is an improvement, it should record this as the new VO2max.
ETA my Garmin will 'hold' the new VO2 max for quite a while. By all means train VO2 max but there's really no need to fuss about it or test it week to week. It's a difficult metric to shift unless you're really unfit to start with. Training VO2max is like trying to make an engine increase capacity/power by repeatedly revving it to the limiter. For me, my 5-10% shifts in body mass have more of an impact on the figure than my absolute output.
Edited by oddman on Tuesday 21st July 09:37
In the heat, I try to either run early in the day or late in the evening.
Rather than run to a pace, run to a heart rate. Can set this up on Garmin, works great.
My V02 max dropped quite a bit after a weeks holiday, no exercise and AI so plenty of drinks! Its taken 4 weeks to get it back to where it was.. running in the heat made it drop so by running to HR instead, means I am back up to where I was.
Rather than run to a pace, run to a heart rate. Can set this up on Garmin, works great.
My V02 max dropped quite a bit after a weeks holiday, no exercise and AI so plenty of drinks! Its taken 4 weeks to get it back to where it was.. running in the heat made it drop so by running to HR instead, means I am back up to where I was.
Ok thanks guys, good to confirm what I thought so I'll be taking my app's opinion with a massive pinch of salt. It has been quite hard mentally to tell myself to slow down my pace......I'd always been of the opinion that I should be going as fast as possible at all times. But it has been nice being able to run further at a slower pace and not feeling like I'm right at the edge of giving up.
UTH said:
Ok thanks guys, good to confirm what I thought so I'll be taking my app's opinion with a massive pinch of salt. It has been quite hard mentally to tell myself to slow down my pace......I'd always been of the opinion that I should be going as fast as possible at all times. But it has been nice being able to run further at a slower pace and not feeling like I'm right at the edge of giving up.
As you get older you'll have to get your head around it 
UTH said:
Ok thanks guys, good to confirm what I thought so I'll be taking my app's opinion with a massive pinch of salt. It has been quite hard mentally to tell myself to slow down my pace......I'd always been of the opinion that I should be going as fast as possible at all times. But it has been nice being able to run further at a slower pace and not feeling like I'm right at the edge of giving up.
The only metric which really counts is the stopwatch.If you want to get faster with minimal effort, you need to do a bit of research on how to train. I self trained from couch via a hilly 1.45 HM age 50 to 2nd place in Age Group Triathlon in two years using this method without significant injury or burnout.
Matt Fitzgerald's 80/20 running is a good place to start.
oddman said:
UTH said:
Ok thanks guys, good to confirm what I thought so I'll be taking my app's opinion with a massive pinch of salt. It has been quite hard mentally to tell myself to slow down my pace......I'd always been of the opinion that I should be going as fast as possible at all times. But it has been nice being able to run further at a slower pace and not feeling like I'm right at the edge of giving up.
The only metric which really counts is the stopwatch.If you want to get faster with minimal effort, you need to do a bit of research on how to train. I self trained from couch via a hilly 1.45 HM age 50 to 2nd place in Age Group Triathlon in two years using this method without significant injury or burnout.
Matt Fitzgerald's 80/20 running is a good place to start.
I set a new PB at parkrun of 23.50 in April. I then had some illness/injuries/holiday and got back to full fitness just as the heatwaves started to hit.
I could not get near that PB at all, a couple of minutes slower and that was at max effort. Felt hot every single week. Started to think I had peaked.
First cool parkrun for a while last Saturday so went for it. 23.34
I could not get near that PB at all, a couple of minutes slower and that was at max effort. Felt hot every single week. Started to think I had peaked.
First cool parkrun for a while last Saturday so went for it. 23.34
MOBB said:
I set a new PB at parkrun of 23.50 in April. I then had some illness/injuries/holiday and got back to full fitness just as the heatwaves started to hit.
I could not get near that PB at all, a couple of minutes slower and that was at max effort. Felt hot every single week. Started to think I had peaked.
First cool parkrun for a while last Saturday so went for it. 23.34
Good intel......as long as I keep my arse in gear and keep at the running, I am very intrigued to see what the cooler weather will do later in the year.....it even gives the end of summer something to vaguely look forward to! I could not get near that PB at all, a couple of minutes slower and that was at max effort. Felt hot every single week. Started to think I had peaked.
First cool parkrun for a while last Saturday so went for it. 23.34
worsy said:
UTH said:
Ok thanks guys, good to confirm what I thought so I'll be taking my app's opinion with a massive pinch of salt. It has been quite hard mentally to tell myself to slow down my pace......I'd always been of the opinion that I should be going as fast as possible at all times. But it has been nice being able to run further at a slower pace and not feeling like I'm right at the edge of giving up.
As you get older you'll have to get your head around it 
I've never run for PB etc just to maintain fitness and thought I'd just look at some stats on where I'm at. So my daily route of 5.37km has me (currently) running it in 29.45. I'm down this week, normally 28.30 is the more consistent but having been away on holiday for 4-weeks it's taking time to get it back to 'normal'.
Running the estimates based on my current pace Google predicts a 10k at 55.20. I haven't run a 10k for over 25yrs and back in my late 30s I was at c47mins. Old age, the gift that keeps on taking
I need to recalibrate my Garmin Vivosmart as it has my route at 3.89miles but mapping it out it's actually 3.33miles. So I'm worse than I thought I was!
Yeah, have noticed this, performance has dropped off, was hitting the 27 min bracket for 5k, 57 ish for 10k.
But, taking a minute or two longer now in the heat, it’s just your cooling system using energy that would otherwise contribute to forward motion.
Am on holiday in an All inclusive in Greece but am making sure I knock out 5k on a treadmill each morning, today’s effort was bang on 30 min as set it at that speed, never really run on a treadmill before. Young lad got on the same time, set it to 5k and lasted seven minutes before gassing out, quite funny when a 20 odd year old can’t match a bloke well into his fifties.
Am looking forward to cooler weather at home with regards to running, was fantasising about a 5C run in drizzle the other day at 28C. Am hoping my times drop a bit, got a two month gap between holidays, week away then a month before my first half marathon, meant to front load my training in readiness.
So, yeah, it’s hard for running at the moment but come autumn you will be shifting some with all that running in the heat under you belt.
But, taking a minute or two longer now in the heat, it’s just your cooling system using energy that would otherwise contribute to forward motion.
Am on holiday in an All inclusive in Greece but am making sure I knock out 5k on a treadmill each morning, today’s effort was bang on 30 min as set it at that speed, never really run on a treadmill before. Young lad got on the same time, set it to 5k and lasted seven minutes before gassing out, quite funny when a 20 odd year old can’t match a bloke well into his fifties.
Am looking forward to cooler weather at home with regards to running, was fantasising about a 5C run in drizzle the other day at 28C. Am hoping my times drop a bit, got a two month gap between holidays, week away then a month before my first half marathon, meant to front load my training in readiness.
So, yeah, it’s hard for running at the moment but come autumn you will be shifting some with all that running in the heat under you belt.
I have been getting back into running recently after injury. I did a few runs during the warm weather. It felt much more difficult at 30°C, especially when humid, than it would have been at a more typical temperature. 6km of laps around a field was enough.
I did feel as if I was acclimatising to the heat towards the end of the warm weather.
As above, don't worry about the pace, just the effort. I do runs on road, on tracks/paths and on grass, so my pace varies anyway.
I did feel as if I was acclimatising to the heat towards the end of the warm weather.
As above, don't worry about the pace, just the effort. I do runs on road, on tracks/paths and on grass, so my pace varies anyway.
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