Heart rate - during a marathon

Dear all,

Just achieved a new PB at the Hampton Court Half (1:40:36). Felt strong throughout and managed a sprint finish.
https://connect.garmin.com/modern/activity/1581651269

Planning to run a sub 3:45 in Paris in April (calculator suggests a 3:31 would even be possible), but paranoid about over-doing it heart-wise (this will be just my second marathon).

What sort of HR% should I be at during a marathon? I know that cardiac drift will occur over the run, so I am wary about maintaining a 7mph pace if my heart reaches a HR% that's unsafe.

I would just push myself through pain without these sorts of indicators and probably injure myself, so any advice would be appreciated.

Thank you.

Dean




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Comments

  • SHADESSHADES ✭✭✭
    edited February 2017
    Unless you have a heart condition you won't be able to push yourself through any pain and do yourself any damage.   What will happen is that you will hit the wall and have a very miserable last few miles.    Marathon running isn't about pushing yourself through any pain, it's about sticking to your race plan by not setting off too fast and trying to maintain that pace as long as you can.

    The average heartrate that I run a marathon is about 85%, average max heart rate not working heart rate.
  • Thanks Shades. That makes good sense. Appreciate your input.

  • SHADESSHADES ✭✭✭
    I don't want you to have a difficult marathon.    You know how well your training has gone and your half marathon PB is good evidence of that so set yourself a sensible pace for the first half of the marathon, the 2nd half will take care of itself.
  • Personally I'd not bother with the HR.

    You've done a 1.40 - so that should translate to you hitting your goal. 

    Set a timer so you run say 3.44 for the marathon - divide that into 42.2km - and pace off of that.

    As you say - cardiac drift will happen so the HR isn't that useful.

    If you've prepared properly and done the long runs too - you should be good to go.
  • Thanks Cougie. Yeah so I'll aim for 8:30 min/mil and see how it goes.
  • Not done Paris - but do they have mile markers ? You may want to convert into Km and go off the Km markers.

    I know GPS isn't accurate enough for London Marathon - all the tunnels and buildings mess it up so its safer to go off the course markers. Not sure if you need to in Paris ?

    Have a good run !
  • If you want to run a marathon following HR I recommend you google the MARCO method. You basically divide the race in thirds and have a gradually rising HR target. I agree the mean would be about 85% maxHR.
  • if you do decide to do it by heart rate let us know how you get on.
  • https://connect.garmin.com/modern/activity/1592141925?share_unique_id=4

    Sunday long run - 20 miles - at approximately marathon pace. Heart rate looking good.

    Feeling confident about cracking 3:45.

    Half marathon last week went very well. https://connect.garmin.com/modern/activity/1581651269?share_unique_id=5

    Thanks for all the tips. Will look into the MARCO method and keep you all posted.
  • Interesting question Dean...  and good answers I think.  The marathon training  book I've followed most (Pfitzinger & Douglas) recommends an average marathon HR of between 83 and 87% so talk of 85% fits bang in the middle of that range.    My own HR seems a bit odd so I've no personal experience I can give other than...  1) I do believe that running the first couple of miles a bit slower than average is a good thing.   And 2) my marathon HR is below that minimum.. around 81% last time - in what was a good PB run.

    I just looked up that MARCO website. Interesting.  It does state that the first 2 miles should be very controlled... maybe around 20s per mile slower than average... so I can see sense in that.   But it also suggests going for a pretty strong negative split. For a 3:20 marathon, it suggests a 1:41/1:39 negative split...  and I don't believe that's the optimum It might be satisfying to conserve energy early on and overtake loads of people in the last few miles but I do believe that a negative split does mean that you probably could have got a faster time if you hadn't conserved so much early on.
  • There is a nice data-driven analysis of whether negative splits are the thing to aim for at http://fellrnr.com/wiki/Negative_Splits. Personally I find it is a good correction to the widespread tendency at all levels to give too much too early, or to correct the fallacy of putting time in the bank. YMMV. Not least, for the sake of pleasure, it means I can enjoy an event like Boston for the first half to two-thirds of the race before the suffering really starts :)

  • I suspect that if you start with the intent of finishing with a big negative split then there's a good chance that you'll conserve too much early on, because you want to make sure.  Logic to me says that you start at a pace you think you can sustain for 26.2 miles but no more - if your judgement is close then sometimes that would end up being a slight negative split, sometimes slightly positive.  Either of those means you're unlikely to have run much quicker with a different strategy.

    Boston is a bit different because if you overcook the first half then the second half will bite back a lot harder than a flat marathon would.  Problem is, it's so tempting to take advantage of the net downhill in the first half.

  • I'm running Boston for the first time this year, and pacing seems to be a dilemma there. My theory has always been to go for consistent splits from start to finish, and ideally being about 30 seconds ahead at halfway. Just enough to act as a cushion (psychologically at least), but not enough that I've overcooked it. I read somewhere that it's a bit like fuel efficiency in a car - if 56mph is the best speed for fuel efficiency, then you'll get a better mpg if you drive at a constant 56mph than if you're constantly changing speed, even if this averages at 56mph. I suppose the trick is finding what pace is the equivalent of 56mph for each runner!
  • Rodeo - there's some useful pacing info for Boston here:

    https://runnersconnect.net/boston-marathon-coach/pace-calculator/

    The spreadsheet seems to be downloadable by members only (whatever that means) but I've got a version from 2008 that I can email you if you PM me.

  • rodeo... just set off at 56mph. Simple.
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