Rather than clog up the 2 x 20's ouch thread I would start my own on about the response Toks made to Michelle concerning HR. The reason I've picked up on Tok's reply ss because during April I spent 12 days in riding in Mallorca and taking my FaCT Level I & II course on Lacate testing & endurance/respiratory training.
The 2 courses I did I had to put aside all my views on training with power & exercise physiolog and think out of the box to learn the FaCT ideas.
Being a devoted power meter user for the last 6 years, logging every ride on Cyclingpeaks I've been shown that a powermeter is just another tool which doesn't replace heart rate monitoring. Yes I know Toks listed the following concerns with HR and I'm not hear to preach to the converted but share a friendly discussion with you that a power meter will not solve the issue Toks mentioned.
Spending the whole time in Mallocra riding only on HR although I've been doing this for the last 3 months anyway and just justing using the powermeter to let me know if my performance has dropped on long steady state rides. On the camp I saw a person rdiding with Watts who claimed he could ride 400W (weigh 90kg) but did not say for how long for, completely fry himself because he did not take note of what his Hr was doing but only Watts. He knew what his Lactate Balance point was which is the determintaion of the body's ability to blance the production of lacatate produced in the working muscles with it's clearance by the body but instead choose to ride by Watts so spent loads of time riding close/above his balance point or during these long endurance rides. End results as said above he ended up underperforming after the first week of the camp.
Being FaCT certified and new to the FaCT ideas I asked Juerg Feldman of FaCT-Canada how I should respond to views held negatively on HR.
Heres the reply I got :-
After a few emails , asking me to give a short summary statement , how I would reply to Rob's question, as they had not the advantage to be in Andrews camp. Well check his web site and sign up for next year in Joshua Tree or some where in Europe Mallorca or perhaps on the mainland in Giverola ..
There is 2 way's how people argue this days wattage versus heart rate followers. I like to give first the traditional answer , but like to go for a more FaCT like information why we think it could be a much more open discussion than a "believe " discussion.
Here the "traditional answer and the interested readers will immediately see where a discussion like that will end up (smile)
TOP WORRYING ABOUT WHAT YOUR Wattage IS DOING!!!!!
RIDE AT WHAT FEELS LIKE 'RACE PACE' (tt OR rr) heart rate OR CLOSE TO RACE PACE heart rate. ITS NICE TO HAVE AN IDEA WHAT YOU AVERAGE Wattage IS DOING FROM TIME TO TIME BUT don't LET POWER, TRAINER SPEED OR PLAIN OLD 'PERCEIVED EXERTION' GOVERN YOUR EFFORTS
Wattage IS FAR TOO In- SENSITIVE (HYDRATION, FATIGUE, ANXIETY, HEAT, LACK OF SLEEP, INCREASED FITNESS, ILLNESS ETC) for a physiological system and WILL AFFECT HEART RATE POSITIVELY OR NEGATIVELY). IF OF COURSE YOU CAN KEEP ALL THE ABOVE CONSISTENT WHICH I ACCEPT SOME PEOPLE CAN DO THEN FINE than wattage may be able to be used as a possible intensity indicator.
FaCT information to the above discussion between Wattage and heart rate.
Wattage is an excellent way of getting overall information, on what performance you are able to push by certain physiological situations. ( in heat. humidity,pre-start situations, "fatigued" glycogen depleted, Illness like bronchitis or other pulmonary restriction).
As you can see, all the points discussed above, where heart rate may be influenced will be true as well for wattage.
You may have a clue, that 240 wattage which may be a 70 % effort under healthy conditions is now still 240 wattage, but unlikely 70 % effort. More likely higher and even above 100 % so you may not be able to push 240 wattage at that given day at all.
So this simple example illustrates very nicely how both, wattage as well as heart rate will be different than under healthy conditions. Now here comes the possible difference. If you still believe 240 wattage is anyway my Zone 3 effort because 240 wattage is always 240 wattage, you may run into some physiological problems.
On the other hand if in a healthy situation 240 wattage was the effort you could push just below LBP by a heart rate of 145 and you control your intensity by heart rate you may now still be able to ride with 145 heart rate as the same physiological effort for your heart but only push 140 wattage, as another physiological system may be of limitation.
So if you look the effort from a cardio point of view you push in a healthy situation 145 beats per min and 3 l SV so your HMV (heart minute volume or how much blood your heart pumps) is the same in the 240 wattage effort as well as in the 140 wattage effort. So you do the same "Zoning" if you just look at your heart rate and cardio system only.
Now as Andrew mentioned , and often misunderstood by "critical" readers , in FaCT we use heart rate as one of the "BIO-markers" to assess possible reasons of lower or higher overall performance ( which can be measured in wattage )
Heart rate as an information of the intensity of your cardio workout or cardio zone.
This is the easiest way of using heart rate, but with all the weakness mentioned in the answer from the UK Friend. Heart rate is very dependent on different influences. ( as is wattage ).
In the above example of 240 - 140 wattage versus heart rate 145, I would argue, you are better on listening to your heart rate.
Now next point. The question now is:
Why is my heart rate so high by already 140 wattage?
True I just can neglect it and push through it ( perhaps) but possibly or better formulated luckily some central governor system may slow me down and will not allow me to maintain 240 wattage and may safe me from "damaging" the physiological systems. True the above example is a "clear†one, if you are sick you will not be able to maintain the same Wattage.
Okay let's take heat instead of illness. Your LBP wattage (or for no LBP users) your threshold intensity is 240 wattage. LBP heart rate is 145 ( Threshold heart rate is 145. Now wattage user will go and hold 240 wattage. we will try to hold 145 heart rate plus some other information we may discuss later as bio -markers ) But let's stay with heart rate to keep it simple for the moment.. Temperature ( heat ) outside is 33 - 34 degrees( true it is warm , but easier to show the overall reactions of "zone" changes due to maintaining heart rate versus wattage. 240 wattage and 145 heart rate and you are 5 min underway. Now lets' go 2 ways. 1. Maintain 240 wattage. You will see an increase of heart rate over time and you move heart rate ways up and up and as you know there is a limit how high you can go with HR.
2. You maintain 145 HR and your wattage will slowly start dropping over time. Now here is a very interesting point, as lot's of people ask about heart rate drift. We have no heart rate drift as you can see, we have a wattage drift.
Short and simple some thoughts. Due to the high temp. Your body has a problem to cool the core temp. and it will increase. Well first before that happened, the body will try to get ride of heat over the skin, opening the blood vessels on the surface and therefore moving lot's of blood to the surface and with it as well O2.
The lack of getting ride of heat due to the outside temp. Will increase the sweat rate and with it the loss of water (dehydration risk) the increase of surface blood flow will add more work to the heart, which will increase the heart rate. This does not will go for free, but requires more O2. The dehydration can lead to a higher viscosity of the blood and will add again more work to the heart and again will require more O2.
Now you have a first problem, that is the limitation of the heart to feed it's own muscle with proper O2 supply and if that is getting top a limit the CGM will start to make some decisions, like reduce motor unit recruitment in the leg muscles.
If now less muscle fibers try to maintain the same wattage, they may have to change the way they can supply ATP and produce ATP from a clear oxygen dependent supply intensity to a now mixed situation of oxygen dependent and partial some are where you may produce oxygen independent (You will see lactate now in the system as a bio marker) now you have to think is 240 wattage still the same intensity zone.
We would argue it is still 240 wattage but physiologically you change into another intensity zone, and in facto changing the stimulation this workout will have on your body..
Now if we keep going here you will see with the increase of the physiological intensity by a fixed 240 wattage a change in RQ (increasing and a decrease in Fe O2 (O2 uptake from the outside.This has different reasons . You may produce, due to the physiological change in the intensity zone more CO2, which will stimulate your respiration rate. This may increase the total air you move per minute , but you may reduce the TV ( volume per breath ) this can change the amount of O2 you move from the lungs to the blood , but as well the increased work for your respiratory system will increase the O2 demand for this vital system.
Summary: heat will increase heart rate ( cardio marker ) which increases the O2 demand for the heart and may start to reduce the ATP production over fat and glucose to more glucose dependent and therefore may change the metabolic situation ( lactate as the marker ).
Now this will change the demand of the respiratory system (breathing frequency as a possible marker) and this can change the O2 sat (SO2 as a possible marker.
Now all the above physiological changes are not typical for a car motor so therefore in a stable system like a car motor wattage is a very good indicator on which car produces more wattage and you can easy maintain this as you feed always the same fuel .
This is based on our ideas not possible or available in a physiological system. ( heat , humidity , illness, energy storage situation , coordination and so on , all will have a direct or indirect influence on the O2 usage and therefore on the ability to maintain a fixed outside power assessment like wattage.
Luckily for most of us, the body parts, which will loose power as a protection for the vital organs, which need the O2 to survive , will be the body parts that move the bike, or the boat or the skis and so on.
The limitation of the available O2 ( VO2 ) will show up in the loss of wattage due to the fact , that the energy generated with the O2 will be needed to move the air to the body ( Respiratory system ) , pump the blood to the organs ( heart ) , keep the brain functioning , keep the temp stable ( core temp. and so on . all this energy demand may far overload the system and the little bit left for the legs may allow you to push 145 heart rate but only 140 wattage.
If you try to neglect this physiological demands and you try to maintain 240 wattage you may be able to do that, if 240 wattage is your recovery zone, but you may move from the recovery zone to the high intensity zone if you take physiological reactions into account. If you just look 240 wattage yes you maintained 240 wattage but have no clue how you produced this 240 wattage.
If like in our example the 240 wattage is LBP wattage or threshold wattage you will "blow†the system, if you try to maintain wattage but neglect the physiological signs.
For the older reader there are 3 classical documented cases in running, where 3 world class runners tried to neglect the physiological signs and kept running with a fixed speed.
1. Jim Peters in the Vancouver Empire Games Marathon 1954
2. Alberto Salazar 1980 in the Falmouth 12 km road race and last but not least for all TV Viewers on the LA games Gabrielle Andersen Schiess the swiss marathon runner.
But some cyclist may remember the first "drug " case in cycling which ended with death on the Mont Ventoux due to drugs, who inhibit the CGM to defend the Vital organs. Some other examples followed 9 read Willy Voets book the Festina Scandal.
So before we believe HR or wattage is the way to go we have to try to understand the values and information one or the other can give us concerns.
1. Health risk
2. Performance benefit.
Hope you can understand why there is no believe in this discussion but some simple ideas on what we actually look for.
Have fun in your drive to stay healthy and find your personal best and limitations. Juerg