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Comment by zimpenfish | Hacker News Reader

(The HN title has "might be" where the page currently has "is".)

> However Teresa Black, along with two other claimants, is arguing that her Fitbit reported a heart-rate of 82 bpm while her personal trainer recorded this at 160 bpm.

I find it somewhat hard to believe that you can be this oblivious as to your own heart rate, especially at high levels.

[Edit for personal anecdata] Also "approaching the maximum recommended heart rate for her age [...] may well have exceeded it, thereby jeopardizing her health and safety" seems a bit far-fetched - I'm not a small fellow by any means and I struggle to get my heart rate up to my max (~180bpm), much less over it[1]. My highest recent was avg.173bpm, max.184bpm for an illness-recovery 10km.

[1] Unless the Garmin HRM is having one of its moments where e.g. it claims I'm sustaining 250bpm for 4 hours.

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> Also "approaching the maximum recommended heart rate for her age [...] may well have exceeded it, thereby jeopardizing her health and safety" seems a bit far-fetched - I'm not a small fellow by any means and I struggle to get my heart rate up to my max (~180bpm), much less over it[1].

Hmm. I'm pretty overweight and can easily go over 180bpm if I'm not watching myself on the treadmill - 5 minutes at 10-11kph will do it.

So how aware are you of your heart-rate?

I'm keenly aware of when my heart-rate rises, I notice it jump if I sprint up a stairwell. When it gets too high I can feel the pressure in my neck and temples. I'm the most out of shape I've ever been at this point in my life and I'm alarmed sometimes at how often my heart-rate stays high after seemingly inconsequential physical exertion so I'm wondering if it's something you tune out when you're really out of shape or overweight.

When I'm doing something active I'm conscious of it. When I'm sitting at a desk I'm not at all conscious of it. I assume it's normal at such times, but how wouldI know if not?

I think it's pretty normal to not be conscious of it when it's at a resting rate. I guess what I meant to say is that I'm conscious of it when it's not at a resting rate and alarmed when it isn't and I feel like it should be.

I can tell when I'm crossing 162bpm (I think it's my personal aerobic threshold). If my HR below that I'm recovering; above that - fatigue starts to build up. Also I can tell when it's above 171 - itchy feeling from lactate start to build up much faster. I did VO2 max test once and went as high as 220. It feels absolutely horrible after 190 (long-time exposure to HR at that level most likely will do permanent damage to heart).

I'm not that overweight (around 77kg for 1.81m). Last week I went for a trial at a gym and tried a treadmill for the first time in my life, I got to 180bpm in around 30secs at 5kph. I don't do much exercise besides walking 5 to 10km almost everyday and the rare (and slow) 10mins run. The bpm were measured by the treadmill itself, not sure how accurate that is.

5kph is walking pace (a shade over 3mph) and I'd guess that 180bpm was inaccurate - may be a doubled 90bpm?

Anecdata: Last summer I was considerably heavier than 77kg, carrying 5kg of stuff, walking 51km in 10 (hot sunny) hours, and averaged 105bpm (max of 119bpm).

Yeah, maybe the reading was incorrect but I do get a spike in bpms whenever I run or climb stairs. I don't get it when walking or weight training. Might need to check this with some exam...

Threadmill lies to me pretty much all the time. In most cases it doesn't even work for me. Unless you have a medical condition, it is very unlikely that you'll get 180bpm from 5km/h walk (mine usually don't go above 150 even going uphill with 20 pounds weight vest on my shoulders). 180bpm is 3 hearbeats every second - pretty easy to check with finger on your wrist.

I came here to say something similar. I truly find it hard to believe that people can't tell the difference between 82 and 160. Especially if you've been working with a trainer who would teach you to listen to your body!

I think for most people your maximum heart rate is your maximum heart rate. That is, there is a certain rate you can reach and there is not any problem with that.

If there is a question about your heart you go to the cardiologist and get a stress test where you have an ECG attached and maybe also they look at your heart with ultrasound and if your are healthy nothing untoward happens.

If you are not healthy there is a risk of arrhythmia and other things that can go wrong. The risk of this is certainly higher if you are older, but young people, even teens, sometimes have sudden cardiac death under stress.

Anyway, I have seen the old electrical types of heart rate monitors do something like this, where the heart rate seems to bounce back and forth between the true rate and 1/2 the true rate and probably there are situations where the monitor picks up every other beat for some reason.

Yup. It's total crap. You're not going to push your heart rate so high you damage yourself, at least not a normal/sane person. If it was a serious risk, we'd all be wearing heart rate straps 24x7 with alarms sent to remind us to sit down when our HR gets into dangerous territory.

I have a Suunto Ambit (GPS, HR strap, altimeter, barometer, etc) and a Fitbit Surge HR I got for Christmas. Sometimes both work, sometimes neither works. You use it for what it is. Typically when they both get a good signal, they're reporting the same figures.

Let me guess, the claimant wasn't wearing the Fitbit the recommended 2-3" above her wrist bone at the time.

[1] Unless the Garmin HRM is having one of its moments where e.g. it claims I'm sustaining 250bpm for 4 hours.

Are you sure you don't have an arrhythmia? My HRM used to do that; turns out I was experiencing supraventricular tachycardia (SVT). I didn't have any symptoms other than my left atrium going bonkers due to a rogue electrical signal in my heart (no lightheadness, no pain, no noticeable loss of athletic performance).

I guess it's possible but it's fairly rare (hasn't happened for a good long while with the new Garmin strap) and is normally fixed by adjusting or swapping the strap for another.

Def. rare, probably no need to panic. Just throwing it out there, as most of the high (or low) readings go away once you get sweaty, or adjust the strap. If the reading stays that high for hours, it's probably worth stopping to adjust the strap, manually check pulse, etc.

Agreed. If you're even just moderately healthy, you can't push your heartrate up until it spirals out of control and you sustain physical damage. What a silly notion. Still, the heart rate being off so drastically does justify at least a complaint - otherwise I could make a wristband that generates random garbage values in the range 70-180 and say it measures heart rate.

> a wristband that generates random garbage values

Oddly, the only HRM I've never (knowingly) had any spurious readings from was my Polar S625X (a decade ago.) Which may be because (IIRC) it had a much lower sample rate than the current Garmin.

'Maximum' heart rate is an urban myth. It's a calculated expected maximum which many people can go above. It's like the speed of a car, rather than the RPM with its redline failure meltdown.

Various things affect HR, for example race-day HR is usually 10BPM higher than normal. For this reason HR is more of a helpful secondary metric for an sport with 'real' metrics like speed/distance/weight.

Did the fitbit put her at risk? Only if she ignored all other signs of overexertion or danger, like chest pains, dizzyness, pounding heart beats, etc.

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