Heart Rate dropping on tri bars

Discussion in 'Australia and New Zealand' started by DaveB, Jan 6, 2007.

  1. DaveB

    DaveB Guest

    In the past I had a feeling my HR dropped when I moved onto the tri bars
    but assumed because of the aerodynamics, that the lower heart rate was
    because of less effort to remain at the same speed. But for the past few
    months I've had the tri bars on my wind trainer bike. I've noticed that
    dropping onto them, but maintaining the same cadence, almost immediately
    drops the HR by 2-3 bpm. Coming back off them then increases HR by that
    2-3 bpm.

    I was discussing this with Gags this morning (if you can call it a
    discussion when my contribution was something like - puff, pant, ...yep
    ...puff, gasp, ... ahuhh ...gasp puff). He was thinking it may be a more
    relaxed position so less stress on the body. I was thinking it may be
    lowering the body requiring less effort for the heart to pump blood
    above itself. Anyone else got a theory? Has anyone else seen this? Come
    on Tam/Carl I'm sure you've got info on this.

    DaveB
     
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  2. rooman

    rooman New Member

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    Hey Dave, so you have a heart! (ducks)

    Not suggesting any expertise on this whatsoever, just theorising and those who know may clear this up.

    maybe you are breathing better when on the tri bars, either due to being more relaxed or you are opening your lungs a touch more ( usually not the case though with narrower elbow position..) better respiration lower heart rate.

    Have you considered also the effect of HR drift?, not just the lag we get with HR as we warm up or exert to AT, but on a continued effort the HR goes above normal expected effort due to a number of factors, hydration, stress, temperature, etc... this may have some bearing, on how your heart rate drift pattern operates .

    I kinda think you are more relaxed and thus see a lower HR for same output...
     
  3. Martin

    Martin Guest

    DaveB wrote:

    > In the past I had a feeling my HR dropped when I moved onto the tri bars
    > but assumed because of the aerodynamics, that the lower heart rate was
    > because of less effort to remain at the same speed. But for the past few
    > months I've had the tri bars on my wind trainer bike. I've noticed that
    > dropping onto them, but maintaining the same cadence, almost immediately
    > drops the HR by 2-3 bpm. Coming back off them then increases HR by that
    > 2-3 bpm.
    >
    > I was discussing this with Gags this morning (if you can call it a
    > discussion when my contribution was something like - puff, pant, ...yep
    > ..puff, gasp, ... ahuhh ...gasp puff). He was thinking it may be a more
    > relaxed position so less stress on the body. I was thinking it may be
    > lowering the body requiring less effort for the heart to pump blood
    > above itself. Anyone else got a theory? Has anyone else seen this? Come
    > on Tam/Carl I'm sure you've got info on this.
    >
    > DaveB


    Very interesting observation. There are pressure sensors (baroreceptors)
    on the carotid arteries in the neck. These pressure sensors have a rapid
    response and lengthen the resting phase of the heart beat when the
    pressure in the carotid arteries rises. They respond within a second or
    two and form a feedback mechanism for short-term control of blood
    pressure. When you lower your head the blood pressure in your carotid
    arteries probably rises slightly (because the difference in hight
    between heart and neck is smaller) and the feedback mechanism lowers
    your heart rate. That's one possible explanation.

    To take things one step further, I think the baroreceptors also affect
    the constriction of all small arteries (also to control blood pressure),
    but this mechanism is slower. If these theories are correct you might
    see your heart rate recover partially after you have been on the tri
    bars for about 30-60 seconds, as the arteries dilate a little to reduce
    blood pressure. The reduction in the pressure caused by the arterial
    dilation would make the baroreceptors increase the heart rate again.
    There might too much other variability in heart rate and not be enough
    resolution in the measurement to see these secondary effects (if they
    exist).

    My lazy Sunday afternoon thoughts.

    Martin

    --
    Removed z before replying by email.
     
  4. TimC

    TimC Guest

    On 2007-01-07, DaveB (aka Bruce)
    was almost, but not quite, entirely unlike tea:
    > In the past I had a feeling my HR dropped when I moved onto the tri bars
    > but assumed because of the aerodynamics, that the lower heart rate was
    > because of less effort to remain at the same speed. But for the past few
    > months I've had the tri bars on my wind trainer bike. I've noticed that
    > dropping onto them, but maintaining the same cadence, almost immediately
    > drops the HR by 2-3 bpm. Coming back off them then increases HR by that
    > 2-3 bpm.
    >
    > I was discussing this with Gags this morning (if you can call it a
    > discussion when my contribution was something like - puff, pant, ...yep
    > ..puff, gasp, ... ahuhh ...gasp puff). He was thinking it may be a more
    > relaxed position so less stress on the body. I was thinking it may be
    > lowering the body requiring less effort for the heart to pump blood
    > above itself. Anyone else got a theory? Has anyone else seen this? Come
    > on Tam/Carl I'm sure you've got info on this.


    Diversion time:

    It's amazing what you learn at height safety certification courses,
    but the heart apparently doesn't pump with enough pressure to pump
    bloody back up from the legs -- it's a pump, not a vacuum cleaner.

    When upright, the body relies on you constantly moving your legs which
    does the pumping. So it's not fidgetting, restlessness or nervousness
    that causes you to walk around and jiggle your feet when you're up in
    front of an audience giving a talk -- it's your circulation in action.

    This enters into height training via what happens when you suffer
    suspension trauma after being fall arrested. Even if not unconcious,
    cycling (ha! bicycle reference!) your legs on an invisible bicycle is
    not enough to pump the blood -- you need to be pushing up against
    something. Or merely having your thighs pulled level with your hips
    is good enough (there are straps on harnesses for this reason), but
    not stretched out vertically. If suspended from your back, stuck
    vertical but not able to rescue yourself (if suspended the usual way
    from your back, unless you have some structure nearby to help maneuvor
    yourself, you won't be able to resue yourself), for more than 20
    minutes before rescue, then the blood pools in your legs, and starts
    getting poisioned with CO2. You will be unconcious at this point.
    Standard first aid will also now kill you. After fainting, standard
    first aid teaches the first aider to place the body level and if
    possible, feet up in the air. This will then cause poisioned blood to
    rush to your brain. The suspension trauma victim must be made to sit,
    legs level with their hips to get the blood to recirculate, but
    *slowly*. Their body must never be allowed to be level with their
    legs, for several hours until recovered. Of course, by this time, the
    paramedics with specialist instruction in suspension trauma are
    already there, right?

    Here endeth longest diversion in history.

    So yeah, having the height difference between the heart and feet
    lowered leading to less stress on the heart sounds plausible.

    --
    TimC
    C Code.
    C Code Run.
    Run, Code, RUN!
    PLEASE!!!! --unknown
     
  5. MikeyOz

    MikeyOz New Member

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    well don't know about being an expert but from fairly extensive Tribar use, yes Heart Rate drops anywhere from 2 to 5 BPM. Think you might find it will just be a gravity thing, blood does not have to travel as far up, so takes less effort from you heart to get it to your noggin and everything else which is now lower. Hence things like when working out Tri specific heart rate training zones, you tend to take this into account if you want to be really padantic, hence one of the contributing factors why you are able to get your heart rate higher when running VERY easily, where as it takes a little more effort while cycling. Swimming as well, you are flat, blood does not have to travel as far. This was my reasoning behind it and I think I read something similar later on while doing some research as well maybe on Trinewbies.com

    I actually find my aerobar position far from comfortable, however, as you have found in terms of heart rate it is much more efficient, drag wise as well.
     
  6. Dave Hughes

    Dave Hughes Guest

    On Sun, 07 Jan 2007 14:28:35 +1100, TimC wrote:


    > It's amazing what you learn at height safety certification courses, but
    > the heart apparently doesn't pump with enough pressure to pump bloody
    > back up from the legs -- it's a pump, not a vacuum cleaner.


    I find that hard to believe. I've seen too many people stand *very* still
    for extended time periods, certainly long enough for there to be some loss
    of circulation if this were the case. However sitting, especially in a
    safety harness, constricts the flow so you can get some blood pooling in
    the feet.

    > If suspended from your back, stuck vertical but not able to rescue
    > yourself (if suspended the usual way from your back, unless you have
    > some structure nearby to help maneuvor yourself, you won't be able to
    > resue yourself), for more than 20 minutes before rescue, then the blood
    > pools in your legs, and starts getting poisioned with CO2.


    That's what I was talking about above. It's a fairly well known thing in
    rock climbing circles that you can't simply hang in a harness for too
    long, so if you think you'll have to you take larger seats so there's
    scope for wriggling. You can also do this to a limited extent in the
    harness.

    --
    Dave Hughes | [email protected]
    "Reading computer manuals without the hardware is as frustrating as
    reading sex manuals without the software." - Arthur C Clarke
     
  7. jur

    jur New Member

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    From the MAPP:

    Body Position on the Bike will Influence Heart Rate. Let's say I am riding on an indoor bicycle trainer with my upper body parallel to the ground (Hands on the drops) at a heart rate of 145. Raising upright while continuing to cycle at the exact same workload will result in an increase in heart rate of about 5 beats per minute. Trust me I have experimented with this effect on many a winter evening! This is due to decreased venous return in the more upright position. Heart rate increases to compensate for the slightly decreased venous return and stroke volume, keeping cardiac output constant. Whe I return to the drops, the heart rate drops again.
     
  8. Dave Hughes

    Dave Hughes Guest

    On Sun, 07 Jan 2007 12:13:56 +1100, DaveB wrote:

    > In the past I had a feeling my HR dropped when I moved onto the tri bars
    > but assumed because of the aerodynamics,

    <snip>
    > Anyone else got a theory?


    It's simple. Using tri-bars makes you a triathlete, and thus you no longer
    require blood to feed the brain. Your heart therefore does less work.

    </troll>
    --
    Dave Hughes | [email protected]
    "SCSI is *not* magic. There are fundamental technical reasons why it is
    necessary to sacrifice a young goat to your SCSI chain now and then."
    - Daniel M. Drucker
     
  9. TimC

    TimC Guest

    On 2007-01-07, MikeyOz (aka Bruce)
    was almost, but not quite, entirely unlike tea:
    > DaveB Wrote:
    >> In the past I had a feeling my HR dropped when I moved onto the tri
    >> bars
    >> but assumed because of the aerodynamics, that the lower heart rate was
    >> because of less effort to remain at the same speed. But for the past
    >> few
    >> months I've had the tri bars on my wind trainer bike. I've noticed
    >> that
    >> dropping onto them, but maintaining the same cadence, almost
    >> immediately
    >> drops the HR by 2-3 bpm. Coming back off them then increases HR by
    >> that
    >> 2-3 bpm.

    >
    > well don't know about being an expert but from fairly extensive Tribar
    > use, yes Heart Rate drops anywhere from 2 to 5 BPM. Think you might
    > find it will just be a gravity thing, blood does not have to travel as
    > far up, so takes less effort from you heart to get it to your noggin
    > and everything else which is now lower.


    Fsck! Another think the bent riders have on us, apart from being able
    to grow really good beards!

    --
    TimC
    Jun 26 14:08:17 kernel: troll-o-meter (pid 15134) killed: memory exhausted
     
  10. TimC

    TimC Guest

    On 2007-01-07, Dave Hughes (aka Bruce)
    was almost, but not quite, entirely unlike tea:
    > On Sun, 07 Jan 2007 12:13:56 +1100, DaveB wrote:
    >
    >> In the past I had a feeling my HR dropped when I moved onto the tri bars
    >> but assumed because of the aerodynamics,

    > <snip>
    >> Anyone else got a theory?

    >
    > It's simple. Using tri-bars makes you a triathlete, and thus you no longer
    > require blood to feed the brain. Your heart therefore does less work.


    Also, they have no heard anyway -- it's just the legs pumping blood.

    > </troll>


    --
    TimC
    hey Beavis, we're segfaulting, heh heh heh, I know, Butthead, so let's
    SIGBUS from inside the handler, heh heh heh --Stephen J. Turnbull
     
  11. In aus.bicycle on Tue, 9 Jan 2007 12:30:42 +1100
    TimC <[email protected]> wrote:
    > On 2007-01-07, MikeyOz (aka Bruce)
    > was almost, but not quite, entirely unlike tea:
    >>
    >> well don't know about being an expert but from fairly extensive Tribar
    >> use, yes Heart Rate drops anywhere from 2 to 5 BPM. Think you might
    >> find it will just be a gravity thing, blood does not have to travel as
    >> far up, so takes less effort from you heart to get it to your noggin
    >> and everything else which is now lower.

    >
    > Fsck! Another think the bent riders have on us, apart from being able
    > to grow really good beards!


    Well would be cause and effect wouldn't it? Where the blood is, the
    beard follows? Would explain why the upright riders shave their
    legs....

    Zebee
     
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