“Apple changed the way the heart rate sensor works on the Apple Watch, changing a technical document that describes the feature, changing the way this feature is described for the Apple Watch,” Kirk McElhearn writes for Kirkville. “Apple updated a technical document about how the heart rate sensor works. They are no longer saying that the Apple Watch reads your heart rate every ten minutes; instead, they say this: ‘Apple Watch attempts to measure your heart rate every 10 minutes, but won’t record it when you’re in motion or your arm is moving.'”
“I think the problem is in the accuracy of the heart rate sensor. As Apple’s technical document explains, the Apple Watch has two types of heart rate sensors. ‘Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment,'” McElhearn writes. “These sensors are used when you are in workout mode. But the device also has other sensors: ‘The heart rate sensor can also use infrared light. This mode is what Apple Watch uses when it measures your heart rate every 10 minutes.’ While it’s a bit ridiculous that this part of the document still talks about 10-minute readings, what’s important to note is that these readings, which seem to be less accurate, are using a different sensor. It seems that Apple found these readings to be unreliable, and simply turned them off.”
“To many users, it looks like Apple pulled a bait-and-switch, promising a certain feature and not delivering it. Apple needs to say whether the change is because of faulty heart rate sensors – which means they have a bigger issue – or because of battery life. And if it’s the latter, they should allow users to choose whether or not the Apple Watch checks their heart rate every ten minutes. Let users decide how they want their battery usage to work,” McElhearn writes. “However, if the heart rate sensors are faulty, simply turning them off, after promising this feature, is a mistake. They should fix them, whether through a software update, or by exchanging the devices. They promised a feature, and they can’t simply pretend that they never did so.”
Read more in the full article here.
MacDailyNews Take: Apple needs to clarify exactly what’s happened here or face the inevitable – and justified – class action lawsuit(s).
Apple’s original heart rate support document stated, in part:
The average heart rate is 72 beats per minute (bpm). As you exercise, your muscles need more oxygen, and your heart beats faster to deliver it. During workouts, the heart rate sensor in Apple Watch measures your heart rate and displays it right on your wrist. You can also check your heart rate at any time using the Heart Rate Glance. And throughout the day, Apple Watch measures your heart rate every 10 minutes and stores it in the Health app. All this information, as well as other data it collects, helps Apple Watch estimate how many calories you’ve burned. And by checking your heart rate during workouts, you can see how both your intensity level and your heart rate change over time.
The heart rate sensor in Apple Watch uses what is known as photoplethysmography. This technology, while difficult to pronounce, is based on a very simple fact: Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. When your heart beats, the blood flow in your wrist — and the green light absorption — is greater. Between beats, it’s less. By flashing its LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute — your heart rate.
The heart rate sensor can also use infrared light. This mode is what Apple Watch uses when it measures your heart rate every 10 minutes. However, if the infrared system isn’t providing an adequate reading, Apple Watch switches to the green LEDs. In addition, the heart rate sensor is designed to compensate for low signal levels by increasing both LED brightness and sampling rate.
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Apple’s latest Apple Watch heart rate support document, modified on May 30, 2015, now states in part:
You can check your heart rate any time using the Heart Rate Glance. And when you’re using the Workout app, Apple Watch measures your heart rate continuously during the workout. This information, as well as other data it collects, helps Apple Watch estimate how many calories you’ve burned. In addition, Apple Watch attempts to measure your heart rate every 10 minutes, but won’t record it when you’re in motion or your arm is moving. Apple Watch stores all your heart rate measurements in the Health app.
The heart rate sensor in Apple Watch uses what is known as photoplethysmography. This technology, while difficult to pronounce, is based on a very simple fact: Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. When your heart beats, the blood flow in your wrist — and the green light absorption — is greater. Between beats, it’s less. By flashing its LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute — your heart rate. In addition, the heart rate sensor is designed to compensate for low signal levels by increasing both LED brightness and sampling rate.
The heart rate sensor can also use infrared light. This mode is what Apple Watch uses when it measures your heart rate every 10 minutes.
Even under ideal conditions, Apple Watch may not be able to get a reliable heart rate reading every time for everybody. And for a small percentage of users, various factors may make it impossible to get any heart rate reading at all.
SEE ALSO:
Heart health app seeing big usage on Apple Watch – May 14, 2015
Apple Watch heart rate data vs. Mio dedicated heart rate monitor – May 7, 2015
Apple Watch once again shows skin tone not a new issue for heart monitors – April 30, 2015
Apple explains Heart Rate on Apple Watch technology – April 20, 2015
Tim Cook, the operational genius! The party is over people. The Apple Watch has had a botched launch and the product may have hardware/feature issues rendering key aspects of it useless.
This is the FIRST new Apple product post Jobs. The rest of the products rest on well oiled machines. I love Apple but the Watch has been a hot mess and it is by no means clear that it will be successful.
And you would have voted down Henry Ford’s Model T and then the Model A …
Everyone I know who buys a first generation product knows they are doing public beta testing and that there may be rough edges. But that is what you get when you live on the cutting edge.
I don’t see the heart rate as a serious issue. I can tell my heart rate quicker than the Apple Watch with my thumb in a couple seconds. I’ve done it all my life.
Bo:
You are not comparing an Apple Watch to a model T. The Model T ushered in mass consumer transportation. The Watch is a smartphone accessory. Get over yourself.
Second: the heart rate monitoring is a big deal. It’s a big feature driving sales of products like Fitbit and was supposed to form a foundation for HealthKit. Heart disease is a major problem as are reactions to medication that affect heart rate, etc. The Apple Watch could help replace Holter Monitors but alas… it doesn’t seem like that’s going to happen now. The point here is heart rate needs to be monitored constantly over longer periods of time to catch abnormalities. Taking your heart rate a few times a day is effectively useless on this front.
Interesting that you would have the gaul to tell anyone they need to ‘get over themselves’ when your narcissistic ejaculate of a troll post is so laden hyperbole and cliche as to almost make me think it satirical.
Seriously, practice what you preach, son..
GruvDOne:
Your post contributes nothing. You say nothing. You just insult people. You’re useless.
The usual troll buffoonery.
You’re a fool…
Pulse oximetry is an accurate way to measure heart rate in most people at rest . Indeed there are apps that do exactly the same thing using the camera on an iPhone .
For those who want or need an accurate continuous HR measurement a bluetooth 2 electrode chest strap is a better choice .
Yes; any class-action lawsuit for this reason would ignorant and useless.
Measuring heart rate during movement gives wrong impression on state of your health.
For example, you might see higher than normal pulse and think it is a tachycardia, while in reality there is no such thing.
Even more importantly, if pulse measurement during movements is not skipped, user can think that their pulse is “not bad overall” and miss bradycardia, which could be dangeous.
Just checked my heart rate data and there are times when it does not record. It’s good to have a record when idle but the main reason I bought it was for measuring heart rate during exercise and it does that very well.
Too bad the heart rate monitoring does not work well during weight lifting or crossfit, only during cardio workouts where your wrist isn’t moving much.
This is why anything outside a chest strap is considered weak.
Wrist/finger heart rate monitors have always been less accurate than chest based ones.
Still can be used.. Just not 100% accurate.
AW does not really work well during weight lifting, but, to be fair, in other situation AW pulse monitor is as accurate as chest band, it was confirmed by comparisons to ECG.
Heart rate has been hit or miss for me during exercise and rest. I chalk it up to version 1.1 technology. That’s sometimes the price you pay for being on the bleeding edge…if this is a software issue, it will get fixed.
As someone who has been involved with medical pulse oximetry since its infancy, I was skeptical of the initial claims. Even in a controlled environment, certain physiological conditions and activities can dramatically effect readings. A wrist mounted sensor would have to overcome a sh..load of artifact. I am glad they tempered their claims. I yield to you on the best way to do it.
Verification of claims has long been a software issue in every company. The problem ? No proofreaders with experience in physiology .. or.. nobody willing to push for getting such proofreaders.
Just makes the case for an active strap. Third party charging straps are already on the market. An active strap could include not only swappable batteries, they could also contain additional sensors to improve accuracy and add additional capabilities. Hope Apple is rethinking this.
its version 1- so I’m sure down the road, maybe 3 or 4 there will be a better heart monitor. I was going to buy the watch- but I wanted the health part. So I’ll just wait a bit longer until its really ready
I suppose they will have to continue trying or remove it altogether and face the embarrassment of saying ‘it didn’t work the way our marketing and support documents told everyone it would.’
Yet another over-blown issue.. This was never intended to replace serious medical monitoring if required.. the only issue I’ve noted with it is that the last update seemed to have changed how often the watch reports heart rate data back to the health app. Which also has already been mentioned and will probably be fixed in the next update, which more than likely will come out during WWDC or shortly there after
Who’s been talking about “serious medical monitoring?” It’s not a portable ECG device, it’s an exercise device (at least this feature is).
For the record heart rate and pulse rate( which the watch measures) are not the same thing . For almost a hundred years the standard for measuring heart rate has been the electrical signals emitted by the heart .
There are many circumstances where threes no 1:1 relationship between heart rate and pulse rate .
I suspect eventually Apple will try to measure Blood pressure with the watch .
Blood pressure measurements require pressure, which is why it uses inflatable cuffs. I can’t see the watch doing that.
I suppose you could calculate blood pressure w/o a cuff if you can accurately determine the size and elasticity of the artery and the rate of flow of the blood at the point of measurement. A heck of lot more complex than a simple inflatable cuff. 😛
I don’t really care that it no longer measures the heart rate every 10 minutes (for the most part), but because it doesn’t it throws off the exercise time because the watch correlates heart rate with gyroscope movement to determine if you are exercising when not using the workout app. This means that the watch inaccurately measures non-workout exercise, which really diminishes the watch’ usefullness.
What we’ve got here is Apple continuing to collect user data after the product release and changing their documentation accordingly. It would be useful to know exactly what they’re talking about as opposed to the vagary of “may not be able to get a reliable heart rate reading every time for everybody.”
But does this equate into a lawsuit? No damage has been done. Apple has made an effort to present more accurate (though vague) information. I can’t imagine any court would bother with complaints regarding this situation.
So, taking bets:
Which “various factors may make it impossible to get any heart rate reading at all. ???
– Natural skin tone?
– Level of tanning?
– Sweat on skin?
– Obesity?
– Anemia?
– Working out equating to warmer skin, confusing the IR sensor? The ‘mood ring’ effect?
– Liver spots?
– Sunspots?
– Elderly skin offers weaker readings than younger skin? (The Mr. Burns Effect).
– Our alien entity overlords don’t register on Watch heartbeat sensors? Vulcan blood?
– The robot apocalypse has already happened and our AI mecha overlords want an excuse for their Watch showing no heartbeat?
Serious question: I would like to buy an AW.
1. It looks cool and is a nice accesory to my iPhone 6
2. It motivates to be more active during a normal day
3. It can be used to track my fitness heart rate. (weights / spinning / crosstrainer / running belt)
Point 1 I am confident is going to be super, point 2 I trust to be true too. It is point 3 which “worries” me. I like to constantly monitor the heart rate, from starting the warming-up untill the winding down, even when the heart rate starts “normal” and ends “normal”. I want it to monitor when I say start and stop only when I say stop. I want it to monitor all the time and not decide for itself it is not monitoring. Can AW do this or should I just forget about that feature OR can I get a chest strap with buetooth and use Apple’s app to record what the chest strap measures?
If not, what other watch would you recommend? I’ll just get the AW for points 1 and 2 🙂