HR versus Cadence (was Powercranks)

Discussion in 'Cycling Equipment' started by DaveH, Feb 29, 2004.

  1. DaveH

    DaveH Guest

    Phil Holman wrote:

    >A method I have used is to ride at a constant power output, say 200watts, starting off at 60 rpm
    >and increasing cadence every 3 minutes until exhaustion and note HR at each cadence. I googled my
    >results which I've previously posted.
    >
    > Cadence Heartrate Power External
    >
    > 60 96 200W 75 100 200W 90 105 200W 105 112 200W 120 132 200W

    This is in fact the complete opposite of what I found when I did the same test. I used an exercise
    bike in the gym. It was a while ago now but I remember being suprised at the result.

    First I warmed up. Then I selected a power that I could sustain for a reasonable period. It was 250W
    in this case. I pedalled at a normal cadence (90) for 2 minutes and my heart rate was 154. I did the
    same for a number of different cadences from about 60 to over 100. In EVERY case my heart rate was
    EXACTLY 154. Not even 1 beat difference!!! I should repeat the test, but then I am sure that some of
    you will repeat this and post a reply.

    I am interested in seeing the relationship of power to heart rate and cadence. If any of you have
    the polar 710 or 720 with power sensor could you please send me some of your records to see if I can
    find any correlation in the real world. I will post the results.

    Does anyone have any comment?

    Dave

    PS Please send emails to: david dot dn dot harton at pdo dot co dot om
     
    Tags:


  2. Richard

    Richard Guest

    My experience is based on riding the taxc at constant speed (sensor on rear wheel yes) my
    heartrate definitely goes up for the higher cadence while at constant speed so in line with the
    numbers of Phil.

    Richard [email protected] (DaveH) wrote in message
    news:<[email protected]>...
    > Phil Holman wrote:
    >
    > >A method I have used is to ride at a constant power output, say 200watts, starting off at 60 rpm
    > >and increasing cadence every 3 minutes until exhaustion and note HR at each cadence. I googled my
    > >results which I've previously posted.
    > >
    > > Cadence Heartrate Power External
    > >
    > > 60 96 200W 75 100 200W 90 105 200W 105 112 200W 120 132 200W
    >
    > This is in fact the complete opposite of what I found when I did the same test. I used an exercise
    > bike in the gym. It was a while ago now but I remember being suprised at the result.
    >
    > First I warmed up. Then I selected a power that I could sustain for a reasonable period. It was
    > 250W in this case. I pedalled at a normal cadence (90) for 2 minutes and my heart rate was 154. I
    > did the same for a number of different cadences from about 60 to over 100. In EVERY case my heart
    > rate was EXACTLY 154. Not even 1 beat difference!!! I should repeat the test, but then I am sure
    > that some of you will repeat this and post a reply.
    >
    > I am interested in seeing the relationship of power to heart rate and cadence. If any of you have
    > the polar 710 or 720 with power sensor could you please send me some of your records to see if I
    > can find any correlation in the real world. I will post the results.
    >
    > Does anyone have any comment?
    >
    > Dave
    >
    > PS Please send emails to: david dot dn dot harton at pdo dot co dot om
     
  3. "DaveH" <[email protected]> wrote in message
    news:[email protected]...
    > Phil Holman wrote:
    >
    > >A method I have used is to ride at a constant power output, say 200watts, starting off at 60 rpm
    > >and increasing cadence every 3 minutes until exhaustion and note HR at each cadence. I googled my
    > >results which I've previously posted.
    > >
    > > Cadence Heartrate Power External
    > >
    > > 60 96 200W 75 100 200W 90 105 200W 105 112 200W 120 132 200W
    >
    > This is in fact the complete opposite of what I found when I did the same test. I used an exercise
    > bike in the gym. It was a while ago now but I remember being suprised at the result.
    >
    > First I warmed up. Then I selected a power that I could sustain for a reasonable period. It was
    > 250W in this case. I pedalled at a normal cadence (90) for 2 minutes and my heart rate was 154. I
    > did the same for a number of different cadences from about 60 to over 100. In EVERY case my heart
    > rate was EXACTLY 154. Not even 1 beat difference!!! I should repeat the test, but then I am sure
    > that some of you will repeat this and post a reply.
    >
    > I am interested in seeing the relationship of power to heart rate and cadence. If any of you have
    > the polar 710 or 720 with power sensor could you please send me some of your records to see if I
    > can find any correlation in the real world. I will post the results.
    >
    > Does anyone have any comment?

    I have a few. On a trainer, the 710 is exactly the wrong way to test this. The 710 gives erratic
    readings on trainers. Even on the road, it can give different readings for different cogs, as the
    distance from the chain and the sensor varies. Use a Computrainer, a Powertap, or an SRM.

    I don't think 2-3 minutes at a cadence is sufficient. Figure that the HR change from increased
    stress will take 30-90 seconds to manifest itself. There's also the issue of HR drift -- at a given
    wattage your HR is going to go up a bit no matter what cadence you choose. So you should at least
    test both ways -- e.g. start at high cadence and go to low and vice versa.

    From my own experience with a Powertap and a Computrainer, I have little doubt that my HR at a given
    power output climbs as the cadence goes above 70. I'm not sure I have specific files to substantiate
    this, but the correlation seems easy to eyeball.

    Lastly, Phil, I'm impressed that you can maintain 200 watts at 90-100bpm. Either you weigh 200lbs or
    you're a damn strong rider.

    regards,

    Jens
     
  4. I made a test keeping my rear whell free (not touching the roller) I checked my heart rate at
    various cadence.

    It gave:
    Cadence HR
    rpm /min
    40 72
    60 75
    71 78
    80 83
    100 93

    It looks like a quadratic function. I believe that rotating legs faster takes more energy to
    fight against body inertia (mainly legs up and down) and friction. My opinion is this is true at
    any power.

    Michel
     
  5. Robert Chung

    Robert Chung Guest

    DaveH wrote:
    >
    > First I warmed up. Then I selected a power that I could sustain for a reasonable period. It was
    > 250W in this case. I pedalled at a normal cadence (90) for 2 minutes and my heart rate was 154. I
    > did the same for a number of different cadences from about 60 to over 100. In EVERY case my heart
    > rate was EXACTLY 154. Not even 1 beat difference!!!

    Yes, I too have had a defective HRM. Fortunately, it was still under warranty and I was able to get
    a replacement.
     
  6. [email protected] (Michel Sabourin) wrote in message news:<[email protected]>...
    > I made a test keeping my rear whell free (not touching the roller) I checked my heart rate at
    > various cadence.

    Thanks for the data, but why not do the same thing using a realistic resistance and constant speed?
    Muscles may well have to fire differently in unloaded pedalling.

    >
    > It gave: Cadence HR rpm /min 40 72 60 75 71 78 80 83 100 93
    >
    > It looks like a quadratic function. I believe that rotating legs faster takes more energy to
    > fight against body inertia (mainly legs up and down) and friction. My opinion is this is true at
    > any power.

    As long as "inertia fighting" energy doesn't mean the work done to accelerate leg masses per se.

    Andrew Bradley
     
  7. Trg

    Trg Guest

    Robert Chung wrote:
    > DaveH wrote:
    >>
    >> First I warmed up. Then I selected a power that I could sustain for a reasonable period. It was
    >> 250W in this case. I pedalled at a normal cadence (90) for 2 minutes and my heart rate was 154. I
    >> did the same for a number of different cadences from about 60 to over 100. In EVERY case my heart
    >> rate was EXACTLY 154. Not even 1 beat difference!!!
    >
    > Yes, I too have had a defective HRM. Fortunately, it was still under warranty and I was able to
    > get a replacement.

    Aren't you jumping to conclusions here? Maybe the HRM is fine and it's his heart that's defective :)
    Or he just has to adjust his limiter screw...
     
  8. trg wrote:
    > Robert Chung wrote:
    >> DaveH wrote:
    >>>
    >>> First I warmed up. Then I selected a power that I could sustain for a reasonable period. It was
    >>> 250W in this case. I pedalled at a normal cadence (90) for 2 minutes and my heart rate was 154.
    >>> I did the same for a number of different cadences from about 60 to over
    >>> 100. In EVERY case my heart rate was EXACTLY 154. Not even 1 beat difference!!!
    >>
    >> Yes, I too have had a defective HRM. Fortunately, it was still under warranty and I was able to
    >> get a replacement.
    >
    > Aren't you jumping to conclusions here? Maybe the HRM is fine and it's his heart that's defective
    > :) Or he just has to adjust his limiter screw...

    I just recently learned that a Beta blocker has this effect on the heart ;)

    --
    Perre

    You have to be smarter than a robot to reply.
     
  9. Trg

    Trg Guest

    Per Elmsäter wrote:
    > trg wrote:
    >> Robert Chung wrote:
    >>> DaveH wrote:
    >>>>
    >>>> First I warmed up. Then I selected a power that I could sustain for a reasonable period. It was
    >>>> 250W in this case. I pedalled at a normal cadence (90) for 2 minutes and my heart rate was 154.
    >>>> I did the same for a number of different cadences from about 60 to over
    >>>> 100. In EVERY case my heart rate was EXACTLY 154. Not even 1 beat difference!!!
    >>>
    >>> Yes, I too have had a defective HRM. Fortunately, it was still under warranty and I was able to
    >>> get a replacement.
    >>
    >> Aren't you jumping to conclusions here? Maybe the HRM is fine and it's his heart that's defective
    >> :) Or he just has to adjust his limiter screw...
    >
    > I just recently learned that a Beta blocker has this effect on the heart ;)
    I found that out as well about 15 years ago. Not a welcome side effect when playing in a squash
    tournement :)
     
Loading...
Loading...