HR versus Cadence (was Powercranks)

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

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
(DaveH) wrote in message om...
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

"DaveH" wrote in message
m...
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

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

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.

(Michel Sabourin) wrote in message . com...
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

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...

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.

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