Cardiac Drift

Quick facts...

Training properly for nearly a year. 40-50 mpw. 10k PB 38:38. Rest HR 40. Max HR 182

Todays 10 mile....

1 - 7:01 Av HR 142

2 - 7:09 Av HR 148

3 - 6:54  Av HR 151

4 -  7:21 Av HR 153

5 - 7:11 Av HR 155

6 - 7:19 Av HR 157

7 - 7:19 Av HR 158

8 - 7:24 Av HR 158

9 - 7:43 Av HR 157

10 - 7:18 Av HR 160

This kind of astronomical rise over 10 miles cannot surely be right? Could someone please offer some reasoning or advice? image


  • What was the terrain like? What was the weather? Was the intensity even throughout?

    I'd suggest running to a specific HR (for you ~125-130) and seeing if the pace remains constant over the run. 

  • Duckinator - thank for speedy response. Flat and 21 degrees; sunny. Felt hard work.

    Most of my running is easy at 136bpm (75%MHR) However my pace always falls by about 1 minute over 6 miles if I keep the HR constant.

  • Dr.DanDr.Dan ✭✭✭

    If you want no drift, you need to slow down. Simples.image

    If you want no drift at the same pace as above, you need to build aerobic base. Run your 10 mile with a MAX HR of 147 bpm - aim to hit 147 by about mile 3, so build up gradually ... forget the pace, just stick at or below 147 for the rest of the run. Repeat this once or twice a week, while doing the rest of your mileage at easy pace (127 bpm for LSR, 135 bpm for the rest of them). When you can consitently run mile 10 is the same pace as mile 3, raise the bar to 149/150 bpm and start again.

  • So is a large part of this (lack of) aerobic fitness? Perhaps I should add that I sweat a lot too.
  • Dr.DanDr.Dan ✭✭✭

    You will always get drift if you run harder than your aerobic capacity can handle. Looks like this effort was at about 85% maxHR which is tough to maintain for 10 miles without drift.

     It's clear that you can't run at this HR and remain aerobic, so you'd need to cut back to, say, 80% maxHR. You should be able to maintain a steady pace at that HR after a few weeks of trying.

  • In addition to what Dr Dan says, your comment "21 degrees; sunny" may have something to do with it.  Quite possible that you were becoming a little dehydrated towards the end, that will make your body work harder, push up HR, etc...

  • Some useful advice there. Dr.DAN is aerobic capacity predetermined like max HR or can it be improved? 40 mins  - I was more than a little dehydratedimage

    What I find interesting is RW state my MP is a sub 3hr 6:52m/m based on 10k PB.

    How interesting though that Power of 10 deem a sub 3 Marathon on par with a sub 36 10k. Don't they read RW? image

  • Aerobic capacity can most certainly be improved - that's what most of our training is for - particularly the long slow runs.  To an extent, max HR can also be improved....

    "Race calculators" which forecast times at one distance from another are usually pretty unreliable at the extreems - marathon and sprint distances.  From a personal viewpoint, they get my times from 3K to half marathon pretty close.  However for 400m my legs just won't go that fast, and marathon I end up some way off the pace.

    Interesting that Power of 10 come out with a different view on the 10K - marathon equivalence.  A girl at our club has done a sub-3 marathon off a 38:xx min 10K PB.

  • I've see a huge thread on aerobic base training on either this site or the US equivalent. 

    Its maybe 5 years old and was linked to in a training post earlier this year.

    Does anyone have the link?,,,knew I should have faved it

  • PhilPubPhilPub ✭✭✭

    I think the link between a 38 mins 10k and a 3 hr marathon is just about realistic.  (I find the RW calculator is a little aggressive in predicting marathon times from shorter distances, and prefer McMillan for this, but it's in the ball-park.)  So actually it confirms what you're seeing with HR drift at slower-than-MP, i.e. you've got the basic speed for a 3 hour marathon but not the required aerobic base fitness.  I also agree, however, that a significant part of it may be down to dehydration - I also sweat a lot and on warm runs this can definitely affect HR/pace over a longish distance.

    I think Dr Dan's on the right track with practising 'high-aerobic' pace but very much sticking to HR, and hoping to see the HR/pace ratio improve over a number of runs, whilst doing lots of easier mileage at a lower HR.

  • 40 minutes wrote (see)

     To an extent, max HR can also be improved....

    Erm, what? MHR can't be increased, only decreased as we get older.
  • OK - not increased, but the rate of decline can be subdued.  There was a US study on middle aged regular competitive cyclists who were shown to have higher max HRs than their couch potatoe equivalents.  It was concluded that years of long intense exercise had protected their mex HR from the usual rate of decline.  Much more impressive were the low resting HRs, and hence the working HR range of the cyclists, compared to the control group.

    Personally I wondered if the couch potatoes could exercise enough to actually reach HR max, but that's another matter...

    Either way, this is a minor side issue to Cop-out's originial question about HRdrift, and his subsequent question about improving aerobic capacity.

  • Today I did an easy flat 6 miles to show you the issues. Granted its 25 degrees and very sunny but in all honesty should I see someone about this?

    1 - 8:03 HR 131

    2 - 8:01 HR 136

    3 - 8:22 HR 137

    4 - 8:52 HR 136

    5 - 9:09 HR 136

    6 - 9:24 HR 136

    Thats a big slow down for anyone.With this sort of drift I'd be lucky to break 5 hours for a Marathon let alone 3!

  • If you were marathon trained, you certainly shouldn't see that sort of drift!

    However, why not try ruling out the sun/heat influence, and have a go at the same route & HR very early one moring while it's still cool?

  • Allow me to dig out some examples from last year:

     This was a 5.2M run, done to 142bpm in similar conditions to yours:

    1 - 8:39/131bpm

    2 - 8:56/135bpm

    3 -  9:12/136bpm

    4 -  9:07/136bpm

    5 - 9:23/136bpm

    5.19 - 8:56/134bpm

    So tons of drift for me as well and hence a pace dropoff. Cardiac drift can be quite severe depending on hydration levels. No, I don't think you need to see anyone. What you will find over time is A. The drift becomes less severe, and B. Your pace @ 136bpm becomes faster.

  • By way of contrast, here's some data from me from my last long run, on a very flat route:

    1 - 8:20 126

    2 - 7:57  134

    3 - 8:12  133

    4 - 8:21  134

    5 - 8:09  138

    6 - 8:08  137

    7 - 8:21  137

    8 - 8:19  137

    9 - 8:23  137

    10 - 8:06  139

    11 - 7:74  143

    12 - 7:16  151

    13 - 6:59  159

    So fairly constant HR & pace for 10 miles; then 3 miles quicker which rather destroyed any evidence of drift!   However, I know that if I'd continued at the 10 mile pace to about 16 miles there would have been an obvioius rise in HR as my endurance isn't that great.

  • Both very interesting ,including your 11th mile 40 minutes image.

    I feel better having read yours Duckinator. Having spent too much time thinking about this today I'm going to weigh myself before and after a run. I think i'm losing too much fluid. After my six miles today I needed to take on 3 litres of water including 500ml of rego and 250ml some lucozade drink.

  • Well spotted!  Mile 11 was 7:44, which makes far more sense.

    Are you sure about that fluid intake?  Don't think I could drink that much, even if it included alcohol...

  • It does sound rather a lot I know but you'll have to trust me.  I did 1 litre immediately after the run and then consumed the remainder over the next hour.

    Seeing your example over 13 miles makes me very envious. I guess we are all made differently. My wife says she can't believe I'm moaning when I do the 10k times I do. Pah! image

  • ... and I'm very envious of your 10K time!  My PB is 40:10.

    Perhaps I just need to drink more?

  • PS Duckinator. Just quickly checked out that link you put up. This could be the info that makes it all understandable. Thanks.
  • Cop-out, are those shade temps you are quoting? I would never try a long run even with a shade temp that high although I probably got away with it when I was younger. If it's out in the sun it'll be way hotter of course. Another small point but personally I would chuck out the data for the first mile as the av HR is reduced a bit by the startup part of the HR curve. That makes your initial data look less dramatic.
  • Yes Joe that was shade temp. I'll give you that 1st mile point but it still pretty disturbing data, even with the temp factor. Today was slightly less awful and over a hilly route....

    1 - 7:45 HR 131

    2 - 8:09 HR 136

    3 - 8:05 HR 137

    4 - 8:28 HR 136

    5 - 8:33 HR 136

    6 - 8:45 HR 137

  • Stick at it Cop-out.  The cardiac drift will slowly reduce but it take 3 weeks to see any improvement and 6 weeks for something really noticeable.  Worth noting that in my experience running in the heat does increase cardiac drift however when it cools down you'll see a dramatic difference.  Hadd training is good advice.
  • Cheers Clearly but I've been doing this for a year now. image Halfway through Hadd this morning and its making a lot more sense. In essence my aerobic capacity is poor. I also belive genetically I'm stuffed due to losing so much in sweat during even moderate exercise. In the above run I weighed myself before and after and lost 1lb 4oz in weight over the 50odd minutes easy run.
  • Cop-out
    You did get me thinking about this, and for the first time ever I've been weighing myself pre & post run.  I'm losing 1-2lb over 5-6 miles in this heat.  It doesn't concern me, so I wouldn't worry about it either.
    The important thing is to start hydrated, and drink consistently afterwards to ensure good recovery for next time (and life in general!)
    Hadd (ie good base training) is excellent stuff, as Clearly says.  Anyone who hasn't done it would benefit from a good cycle of it.  I'm not following it at present as my training is currently at the other end of the spectrum, but I shall return to it after my Autumn half marathon before I hit my marathon training programme.

  • CO, aerobic base training requires  the patience of a saint and you'll often feel like you're going backwards for periods of time. It's important to look at the big picture and guage progress over 6 months rather than a month or so.

    I'm sure Dan will be happy to give you his progression over the last few months nad from when he started as he's been a perfect example of just how good a runner it can make you. 

  • Ok. Final post before I let this thread die.

    Posted because I think it shows some normality in race conditions.

    Last night I did the Pewsey midweek 5 miler. Its a road race and hilly/undulating.

    1 - 6:02 HR 161

    2 - 6:09 HR 170

    3 - 6:21 HR 171

    4 - 6:17 HR 171

    5 - 6:21 HR 174

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