Viewing 21 posts - 1 through 21 (of 21 total)
  • Sports Scientists – Variable max HR?
  • J-R
    Full Member

    Here’s a question for any sports scientists out there.

    We are told we have a max HR and that exercising at different percentages corresponds to different levels of exertion, from cruise all day upto flat out sprint.

    But I find that when I start riding it’s difficult to get my HR up to 150, even when I am going flat out. 10-15 mins later I’ll exceed 160 if I am pushing, at after 20-30mins my max is mid 170’s and I can happily ride at 150-160 for well over an hour. By the end of a long ride I can hit mid 180’s on short sprints. And from riding hill reps I’ve found that my power at an initial 150 is about the same as my power at 170 several reps later.

    So it appears as if my HR corresponding to each zone drifts up substantially over 30mins or more. Is this a well known effect? I’ve never seen in mentioned anywhere.

    scaredypants
    Full Member

    vulcan, or timelord ?

    Kitz_Chris
    Free Member

    It’s called “warming up”, and I think it’s a reasonably well known phenomenon!

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    thomthumb
    Free Member

    It’s called “warming up”, and I think it’s a reasonably well known phenomenon!

    boom.

    Onzadog
    Free Member

    Cardiac drift.

    jameso
    Full Member

    Warm up, and true max HR is very hard to hit and do much for a while afterwards. Percentage of LTHR seems to be a better training benchmark and ‘easier’ to establish but needs regular self-testing or race data to see where your LTHR is at the time.
    (no sports scientist here, just some of what I read up this year. Joe Friel’s blog – recommended)

    J-R
    Full Member

    It’s called “warming up”, and I think it’s a reasonably well known phenomenon!

    Hmmmm…so when I am “warmed up” I need an HR of 165 to generate the same power as I generate on my first hill rep at HR 145. And I’ve ridden 15mins at moderate pace to get to the hill first, which I thought would be a warm up.

    Cardiac Drift – that article shows exactly what I see on my Garmin traces, so that must be it. Thanks guys.

    It is starnge that so many people talk about their max HR as if it is fixed number, but in fact it will generally be rising during a ride so at a constant HR they will be working less and less hard.

    crikey
    Free Member

    I am still seeing my max HR varying with time.

    You’re not seeing your max HR.

    Max HR implies you have ridden the last minute or so at a pace that has seen you working at full anaerobic capacity and now need to stop because you simply cannot function anymore until you rest.

    It’s not simply riding a bit quick.

    Max HR should equal vision blurring and almost vomiting.

    The-Swedish-Chef
    Free Member

    Max HR is also sport specific, so your running and cycling ones may be very different.

    molgrips
    Free Member

    Best way to get max HR – find a really long steady climb, a 20 minute/half hour job, that has a really steep technical kick at the end. Tal y Maes in the Black Mountains aka The Hermitage is perfect for this. You comfortably settle in right at your threshold for a nice long time then you think ‘there’s no way I’m dabbing 100 yards from the end after 40 mins of slog’ so you give it everything, but it’s dead steep, rocky and technical, so you really have to go for it.. but the end is soo close…

    thomthumb
    Free Member

    i’m not entirely sure that a bike ridden on the road/ trail is the place to get your max HR. when i’ve done max HR test on the turbo/ gym bike i have been unable to see, unable to think. can’t see that i’d have the control to keep a bike in a straight line or upright.

    Technical kick at the end.

    certainly wouldn’t be able to do a tech climb.

    IMO

    jameso
    Full Member

    ^ agreed. I don’t think you even need to know your max HR. Threshold is the effective max you can sustain and that’s all you’re trying to train, a real max is quite hard to hit so many riders will be training by setting zones off a ‘max’ maybe 10 beats lower. I did a max HR test myself once 10 years ago, thought I was going to have a heart attack in my late 20s and never want to get to that point again. Felt a proper state for a while afterwards. Certainly wasn’t a clever thing to do on a road climb and I don’t think I’ve got within 5-10bpm of that since even training my hardest or straining on my SS.

    J-R
    Full Member

    But even if “threshold” is a more useful point on the HR range than max, I assume my HR @ threshold is subject to cardiac drift in the same way as max HR?

    big_n_daft
    Free Member

    that’s why people train using power rather than HR

    Superficial
    Free Member

    That would stand to reason, yes.

    Your HRmax is just that – the maximum it can be (on a bike). Not the maximum you get to on a ride where you try fairly hard, or the maximum you get to before warming up / ‘drifting’. You may not be able to achieve your HRmax within the first half an hour of running, or even at all.

    Having said that, anecdotally I’ve witnessed a few exercise stress tests (used predominantly to diagnose angina) and I was surprised that most people seem to be able to reach their predicted HRmax (using the 220-age formula). Generally, these people are not the fittest specimens (often sedentary/overweight/smokers) but the treadmill ramps up the speed/gradient very effectively that most people can achieve their target HR within 10-15minutes. No cardiac drift required 😀

    jameso
    Full Member

    J-R, I guess so, beyond my knowledge though. I found my LTHR was about +/-3bpm when doing turbo sessions at a max sustainable pace over a set time period. Heat and fatigue from other sessions affected whether I could hit the right level but HR seemed fairly consistent when I could, raised a little as I got fitter. I worked on perceived max sustainable 25-30 min effort and just checked my HR as I went.
    Does drift affect all of us or is it inconsistent? Didn’t say in the links. Interested as many of us CBA with power meter expenses but still want to get the best from any training we do.

    DanW
    Free Member

    that’s why people train using power rather than HR

    Basically this.

    We are told we have a max HR and that exercising at different percentages corresponds to different levels of exertion, from cruise all day upto flat out sprint.

    These guidelines are quite general and get you roughly in the right areas. Even power does not eliminate all possible variation but it probably beats taking blood samples other more detailed and less practical measures throughout exercise 😀 You will never be able to train to the Watt or to the exact BPM

    molgrips
    Free Member

    Mu point about the technical bit at the end of a long climb is that is what encourages you to try that hard and in the right conditions. Simply sprinting your guts out on a turbo might cause you to stop due to muscle pain well before your heart gets high. Lab conditions aside of course, I am talking about general riding and DIY.

    But it raises an interesting point. Lots of things will affect how far you can or will push yourself in a test, and how your body reacts. I think what determines your maximum exertion is quite complicated.

    iamtheresurrection
    Full Member

    I’m with Molgrips. Every one of my max heart rates have come at the end of an off road climb. Last one was the climb up to Captain Cooks monument, 199 clearing the final naggery bit at the top.

    Once sat at 190+ for about five minutes on a road climb up Grenoble. Backed off when I lost colour out of my vision, vomited shortly afterwards… Wasn’t pleasant.

    MulletusMaximus
    Free Member

    Like many here I race and train using heart rate zones. I race TT’s Road and cyclocross to an okay level.

    I use the LTHR explained in Joe Friels training bible. To calculate you LTHR zones you need to warm up well (30 mins) then do a 30 minute session where you go as hard as you can, RPE of about 17+. After 10 minutes hit you lap button and then take you average heart rate for the last 20 minutes. This will then be your LTHR. From there you can find you hear rate zones to train in.

    See link. http://www.trainingbible.com/joesblog/2009/11/quick-guide-to-setting-zones.html

    Setting Heart Rate Zones (Running and Cycling)
    Step 1. Determine your lactate threshold heart rate (LTHR) with a short test. (Do not use 220 minus your age to find max heart rate as this is as likely to be wrong as right. This is explained in detail in Total Heart Rate Training.) This LTHR test is best done early in the Base and Build periods.

    To find your LTHR do a 30-minute time trial all by yourself (no training partners and not in a race). Again, it should be done as if it was a race for the entire 30 minutes. But at 10 minutes into the test click the lap button on your heart rate monitor. When done look to see what your average heart rate was for the last 20 minutes. That number is an approximation of your LTHR.

    Note: I am frequently asked if you should go hard for the first 10 minutes. The answer is yes. Go hard for the entire 30 minutes. But be aware that most people doing this test go too hard the first few minutes and then gradually slow down for the remainder. That will give you inaccurate results. The more times you do this test the more accurate your LTHR is likely to become as you will learn to pace yourself better at the start.

    Step 2. Establish your training zones. Use the following guide to establish each zone by sport.

    Run Zones
    Zone 1 Less than 85% of LTHR
    Zone 2 85% to 89% of LTHR
    Zone 3 90% to 94% of LTHR
    Zone 4 95% to 99% of LTHR
    Zone 5a 100% to 102% of LTHR
    Zone 5b 103% to 106% of LTHR
    Zone 5c More than 106% of LTHR

    Bike Zones
    Zone 1 Less than 81% of LTHR
    Zone 2 81% to 89% of LTHR
    Zone 3 90% to 93% of LTHR
    Zone 4 94% to 99% of LTHR
    Zone 5a 100% to 102% of LTHR
    Zone 5b 103% to 106% of LTHR
    Zone 5c More than 106% of LTHR

    A max heart rate will be easier to achieve in race situations that in training.

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