Heart rate theory

[ZootHornRollo]

This is with respect to cycling really but it's largely the same score with running, so here goes.

At my spin classes (which are more like group turbo sessions) we use Suunto heart rate monitors and their five-zone system which is calibrated by percentages of max heart rate.
I estimated my MaxHR a year or two ago by doing a sort of self-inflicted lactate threshold test, which gave me a LTHR of 165.
The Suunto zones put your LTHR at 85% of max, the border between zones 3 & 4. (Zone 4-5 border is 92%.)
So in order to set my zones I put my max at 194.

Now, I just did a class where I pushed v.hard and recorded an average HR of 178 (91% of estimated max) over 53 minutes.
Isolating the last 30 mins the average was higher, something like 181.
Now, I've got all sorts of Qns:

1. Does this mean I need to readjust my HR zones up? Accepted advice on how to estimate LTHR says knock about 5% off your 40-minute max effort HR - so that would put my LTHR at something more like 170-1. (So my max should be set somewhere around 200 on this system - even if that is not my actual max).
2. Other HR systems put your LTHR at more like 87-88% of max, and it varies between individuals, no? Could it just mean that my LTHR rather than being 85 per cent of my max, is actually 90% of my max? And is this a sign of fitness, i.e., do fitter people generally have a higher LTHR as percentage of max HR?
3. Does your LTHR change over time? Does it go up or down as you get fitter?
4. Could it just mean I was tired / had a bug and therefore had inflated HR? It was also hot in there: do the same efforts power-wise produce higher HRs in hotter conditions?
(5. Should I just save myself the bother and forget about bloody heart rates altogether?)

Phew. And thanks in advance.

[elliptic]

Errr, why are you trying to estimate your max HR in such a roundabout way? Just test it directly...

And yes, training can raise your lactate threshold HR by a noticeable amount, its not a fixed percentage.

[ZootHornRollo]

Errr, why are you trying to estimate your max HR in such a roundabout way? Just test it directly...

And yes, training can raise your lactate threshold HR by a noticeable amount, its not a fixed percentage.

Fair point - I should do a ramp test or the like.

[elliptic]

Yeah, I go out once a year on the road bike and just go flat out to failure uphill then fall over dribbling on the verge

One thing I've noticed is max HR comes down over the years but threshold HR (when I'm fit) less so.

If you were under recovered or ill then more likely to see lower HRs not higher ones in my experience.

[CL]

Why are you bothering with all that baggage Zoot? Can't you tell how hard you are working? No 5.

[ZootHornRollo]

Why are you bothering with all that baggage Zoot? Can't you tell how hard you are working? No 5.

yes well, I don't when I'm out on the bike - just in these spin classes: they give you HR monitors
at each class and everyone's readout is displayed on a screen at the front.
You don't have to wear the HRM though I suppose. It does however give you something to concentrate on - I find indoor cycling a bit, er, mentally taxing otherwise.

[Mike T]

Anyone into this? The idea behind it, I understand from limited reading - to read in depth it would seem you have to buy access or a book - is that if you have a diet relatively low in carbohydrate (compared to a normal training diet) and run more slowly to start with ( at a speed determined by a laboratory test that analyses O2 uptake and CO2 output), you will in time increase your body's use of fat as a fuel and eventually be able to run faster for longer as fat stores are of course huge compared to glycogen stores. As a short cut, people can do without the test and just aim at a particular heart rate for age - about 20 below what most people do most of their training at.

The cynical part of me says this is all nonsense and is only being promoted as there is money to be made, and in America in particular, weight to be lost.

Does anyone know of any studies into this approach?

[zephr]

I thought that was the general idea of starting out with long slow base miles- so that you became more efficient at lipid hydrolysis rather than carbohydrate. Ok, so when you begin it will be really really slow, but then you get a faster baseline whilst burning fat, rather than carbs... eventually your "fatburning" slow speed becomes as fast as other peoples "carb burning" speed, and hey presto you're a super-duper long distance runner.

Unfortunately, no, I don't know of any studies... at least, certainly not any high quality ones.

[Mike T]

I had always thought that starting off with slow running was to let the bones/joints/ligaments/tendons get used to the process - but metabolic changes will also take place.

The Heart Rate Theory thread looks at all this from a slightly different point of view.

I think it would be worth joining the threads together if that can be done.