Heart Rate Zones and Maximum Heart Rate

Nighflame said:

my maximum Heart Rate is 168 (220 - age formula).

You should never use that formula. It is almost always incorrect. Start by correcting the max heart rate so all the zones will be more correct.

My heart rate is set to 200. I'm 45 years old, but I believe that my max heart rate is even higher because during races I often spend the full race in 180-190. When I'm in good form during the running season I will try to do a lab test.

Yes, the one size fits all formula does not seem great.

The problem is when I use my max heart rate of 190bpm (which based on my tests seems to be more accurate for me), other activities apart from running hardly register in Zones.

Zone 1 = 95 - 114

Zone 2 = 114 - 133

Zone 3 = 133 - 152

But this means on a Brisk Walk (7kmph) I hardly get in Zone 2, and never Zone 3 no matter how fast I walk. And on a slow stroll I sometimes don't even get in Zone 1, and most of the walk is classed as resting.

I am missing something.

You can change the zones in any way you like.

I don't see anything odd that you don't reach zone 2-3 for walking or sometimes not even reaching zone 1. Your heart and lungs got no problem providing your muscles with oxygen and venting CO2 so no need to raise the heart rate too much.

I never reach higher than zone 1 for walking. Walking is not strenuous for most people.

Here's my understanding...

MAXIMUM HEART RATE

By default, Garmin uses a mathematical formula to guesstimate your maximum heart rate: 220 - your age.

There are other mathematical formulae which are supposed to be more accurate as they are adjusted for people over a certain age, or for generally active people. However, the simple fact is that a mathematical formula is, and always will be, a guesstimate. It could in fact be way off. The only way to really know your maximum heart rate is by doing a lab or field test. Given that it is so important it is worth knowing!

HEART RATE ZONES

With Garmin there are 5 heart rate zones which give a guide to the intensity of the effort during an activity (Zone 1 easiest to Zone 5 the most intense). There are several widely used methods for calculating heart rate zones. Garmin supports the use of any one of the following methods:

• Based on percentages of maximum heart rate. This is the Garmin default method and only uses the maximum heart rate to calculate zones
• Based on percentages of heart rate reserve added to the resting heart rate (Karvonen Formula). This method uses the maximum heart rate and the resting heart rate to calculate zones. HR reserve = HR max - HR rest
• Based on percentages of lactate threshold heart rate. This method only uses the heart rate at the lactate threshold to calculate zones

The zones will be completely different based on the method used. For example, Zone 1 will have much lower bounds when it is based on a percentage of the maximum heart rate (first method above), than if it was based on the same percentage of the heart rate reserve added to the resting heart rate (second method above).

There is a lot of discussion about which method is the best, but no one size fits all.

INTENSITY MINUTES

Weekly intensity minutes are achieved by performing at least 10 consecutive minutes of moderate to vigorous intensity minutes. Weekly intensity minutes is the sum of the moderate and vigorous activity minutes. The vigorous intensity minutes are doubled when added.

To define what is an intensity minute Garmin can be configured as:

• Auto: A Garmin algorithm is used to calculate what is an intensity minute. The algorithm is not documented anywhere.
• Heart rate zones: The heart rate zones are used to define what are moderate and vigorous intensity minutes. Zone 3 is moderate and Zone 4 and 5 are vigorous.

Now, the WHO defines a minimum of 150 weekly intensity minutes. However, the Garmin definition of an intensity minute is either based on a Garmin algorithm with no documentation, or heart rate zones which can vary significantly based on the method used.

For me this makes the Garmin intensity minutes a meaningless and very misleading unless someone can tell me otherwise!

Hope this helps.

KnightAzul

Auto: A Garmin algorithm is used to calculate what is an intensity minute. The algorithm is not documented anywhere.

Yes, it is true the exact algorithm was not disclosed, but Garmin published quite a few details about it, for example in the document How Does the Intensity Minutes Feature Work? Find some quotes from it, below:

• Your current heart rate is compared to your average resting heart rate.
• Your age, weight, height, and resting heart rate as calculated by your Garmin watch also factor into intensity minutes credit. 
• You must reach or exceed 10 consecutive minutes where either your step count rate or heart rate is elevated above the threshold that is considered moderate intensity.
• After the 10 minute threshold has been met then you will have earned 10 intensity minutes which will continue to accrue if you remain in your moderate or vigorous zones.
• Performing a more vigorous activity resulting in a high heart rate can double your credit minutes, allowing you to meet your weekly goal faster. 
• Most watches with wrist-based heart rate sensors will calculate intensity minutes by comparing your current heart rate to your average resting heart rate

The crucial term throughout the document is the Average Resting Heart Rate. It means if you do not wear the watch round the clock (including the periods of deep rest, and/or during sleep), you will not get the right avg. RHR, and hence also the calculation of the IM will be incorrect.

> By default, Garmin uses a mathematical formula to guesstimate your maximum heart rate: 220 - your age.

Was not expecting this after reading the "YOU RUN, IT THINKS" marketing. Thought it might see the Max and Sustained Heart Rates in an activity and adjust Max HR accordingly.

Anyway put my new tested Max HR in. This means Zone 1 is way above my Resting Heart Rate.

Upshot is that sitting on the couch eating chips is in the same Heart Rate Zone (0) as walking 5km, using most HR formulas based on Max Heart Rate (and Resting HR).

I'll read some more websites about training by Heart Rate Zone.

Anyway, let me give the Auto a try for Intensity Minutes.

Nighflame said:

> By default, Garmin uses a mathematical formula to guesstimate your maximum heart rate: 220 - your age.

Was not expecting this after reading the "YOU RUN, IT THINKS" marketing. Thought it might see the Max and Sustained Heart Rates in an activity and adjust Max HR accordingly.

That's not me who wrote it, and it is also not necessarily so. Recent Garmin watches indeed have the option to detect your max HR, or even to detect your Lactate Threshold, and adjust the HR zones accordingly.

Instead of estimating my max heart rate and I did some sprint tests up a hill and the max I could get my heart rate up to 172bpm (which is kinda inline with my age expectation), but on a 10km run I can sustain an average of 165bpm.

A Brisk Walk (7kmph) of 10km and I did not get above 90bpm and so mostly no-zone and equivalent to sitting on the couch.

None of my heart rate observations on my Garmin match how I have read heart rate is supposed to behave on the Internet.

In the end I turned off heart rate monitoring.And now Interestingly where I was getting zero Intensity Minutes for a 7kmph brisk walk, I now get 100 Intensity Minutes!

Nighflame said:

Instead of estimating my max heart rate and I did some sprint tests up a hill and the max I could get my heart rate up to 172bpm (which is kinda inline with my age expectation), but on a 10km run I can sustain an average of 165bpm.

A Brisk Walk (7kmph) of 10km and I did not get above 90bpm and so mostly no-zone and equivalent to sitting on the couch.

As I explained previously, it is not the Max HR alone, rather the Resting HR (de facto the minimal HR) that is primarily decisive for the Intensity minutes. Hence if your Resting HR is high, for example because you are turning off the HR, or not wearing the watch when sleeping or at deep rest, then it will be difficult to get any IM.

Nighflame said:

In the end I turned off heart rate monitoring.And now Interestingly where I was getting zero Intensity Minutes for a 7kmph brisk walk, I now get 100 Intensity Minutes!

That's also documented in the previously linked FAQ about IM. When no HRM is available, the frequency of steps is being used. That's a much less accurate method, of course, and it will not credit any workouts that do not generate (frequent) steps, regardless how hard they are. But if you are OK with it, and do not need the HR monitoring for other purposes, do not care about the Calories counting, then why not:

Frequency of Steps
The number of steps per minute you take is analyzed. For example, you can earn intensity minutes credit once a brisk walk or running is detected. If no heart rate sensor is present, only moderate intensity minutes will be credited.

Your age, weight, height, and resting heart rate calculated by your Garmin watch also factor into intensity minutes credit.

> Hence if your Resting HR is high, for example because you are turning off the HR,

> or not wearing the watch when sleeping or at deep rest, then it will be difficult to get any IM.

Wearing all day and sleeping with watch my resting HR was 50.

So resting = 50, max = 172bpm, Can average 165bpm for an hour on a run. Brisk walk hardly raises heart rate, run sends it off the charts. I think I have misunderstood how heart rate zones work, let me re-read all the posts again, otherwise a trip to the doctors might be in order!