3 ms·

> However, I doubt that it's that accurate. How accurate is accurate? As someone who works out casually, I'd be happy with something that gave even ± 10 bpm, b

by Osmium 12y ago

> However, I doubt that it's that accurate. How accurate is accurate? As someone who works out casually, I'd be happy with something that gave even ± 10 bpm, because that'd be far more information than I currently have. If, however, as another poster speculated it's more of the case that it only works intermittently, then that's a deal breaker.

IgorPartola 12y ago
I think it'd be intermittent. The problem is that you move around too much when you work out. An simple electrical sensor needs constant contact with your skin to read your HR. If it comes loose, it won't give you a wrong reading, it'll give you no reading. This is the current state of the art. The optical HRM thing they are saying they have is likely to have the same problem. I doubt it'd give you bad data, just no data.
- Osmium 12y ago
  Do you think that'd be the case even if you tighten the strap significantly for a workout?
  - IgorPartola 12y ago
    Yes. It's not just good contact. It's about good electrical contact. For example, if the strap is dry, even if it's directly on the skin, it won't pick up a signal. I suspect that this optical LED-based HRM tech is going to have its own problems. For example, if it has to sit close to a vein, and you move it slightly. Or if it has to be relatively tight on the wrist. Or if the LED's get dirty because of sweat.
    - Osmium 12y ago
      Thanks for the feedback--that's interesting. I'd assumed these were all LED based. If it is electrical contact related, could you not use a gel like another commenter mentioned using with a chest strap? It seems like a gimmick, but I've had good results with one of the iPhone apps where you place your finger over the camera and it's illuminated by the flash. You have to keep the finger in a constant position, but it works reliably if you do. So I have hope for new technology. Completely different area, but there's this technology: http://people.csail.mit.edu/mrub/vidmag/ http://people.csail.mit.edu/mrub/vidmag/ which seems surprisingly robust. If you can get heart rate from standard video, I wouldn't be surprised to find it's possible to get a reliable signal with a LED and light sensor placed directly against the skin–especially if it's done in addition to an electrical signal. Either way, we'll find out soon enough. The Apple watch claims to give heart rate too, and they're going to get absolutely slammed in the media if they don't live up to it. Will be interesting to see!
    - mikestew 12y ago
      A bit off-topic, but I find it interesting how your experience differs from mine. Most of the time I slap my strap on bone dry and it works fine. If not, a little lick on each electrode gets it working. I do have some gel I bought at the behest of my wife, because she finds the application of saliva to be disgusting. Right, because it's gross to put spit on something that's going to be stewing in my sweaty juices in just a few minutes. But once it's working, it stays working (probably because I sweat profusely during exercise). Anyway, I wonder if the difference is body chemistry, maybe you have a little more fat (single digit % here), or who knows what.
mikestew 12y ago
As far as I can tell from using two optical HR devices, the accuracy is all over the place during exercise. So it's not as simple as -+X bpm. If that were the case I could live with it for sufficiently small values of X. But X may be 10, it may then go to 40 (no, I'm not exaggerating), then down to 5 or less. Like a bathroom scale, accuracy isn't an issue if it's consistently inaccurate. But during exercise optical HR monitors give the appearance of being a RNG with LED lights, without the advantage of sufficient entropy to be used for cryptography. IOW, kinda useless.

by Osmium 12y ago

IgorPartola 12y ago

I think it'd be intermittent. The problem is that you move around too much when you work out. An simple electrical sensor needs constant contact with your skin to read your HR. If it comes loose, it won't give you a wrong reading, it'll give you no reading. This is the current state of the art. The optical HRM thing they are saying they have is likely to have the same problem. I doubt it'd give you bad data, just no data.

Osmium 12y ago
Do you think that'd be the case even if you tighten the strap significantly for a workout?
- IgorPartola 12y ago
  Yes. It's not just good contact. It's about good electrical contact. For example, if the strap is dry, even if it's directly on the skin, it won't pick up a signal. I suspect that this optical LED-based HRM tech is going to have its own problems. For example, if it has to sit close to a vein, and you move it slightly. Or if it has to be relatively tight on the wrist. Or if the LED's get dirty because of sweat.
  - Osmium 12y ago
    Thanks for the feedback--that's interesting. I'd assumed these were all LED based. If it is electrical contact related, could you not use a gel like another commenter mentioned using with a chest strap? It seems like a gimmick, but I've had good results with one of the iPhone apps where you place your finger over the camera and it's illuminated by the flash. You have to keep the finger in a constant position, but it works reliably if you do. So I have hope for new technology. Completely different area, but there's this technology: http://people.csail.mit.edu/mrub/vidmag/ http://people.csail.mit.edu/mrub/vidmag/ which seems surprisingly robust. If you can get heart rate from standard video, I wouldn't be surprised to find it's possible to get a reliable signal with a LED and light sensor placed directly against the skin–especially if it's done in addition to an electrical signal. Either way, we'll find out soon enough. The Apple watch claims to give heart rate too, and they're going to get absolutely slammed in the media if they don't live up to it. Will be interesting to see!
  - mikestew 12y ago
    A bit off-topic, but I find it interesting how your experience differs from mine. Most of the time I slap my strap on bone dry and it works fine. If not, a little lick on each electrode gets it working. I do have some gel I bought at the behest of my wife, because she finds the application of saliva to be disgusting. Right, because it's gross to put spit on something that's going to be stewing in my sweaty juices in just a few minutes. But once it's working, it stays working (probably because I sweat profusely during exercise). Anyway, I wonder if the difference is body chemistry, maybe you have a little more fat (single digit % here), or who knows what.

mikestew 12y ago

As far as I can tell from using two optical HR devices, the accuracy is all over the place during exercise. So it's not as simple as -+X bpm. If that were the case I could live with it for sufficiently small values of X. But X may be 10, it may then go to 40 (no, I'm not exaggerating), then down to 5 or less. Like a bathroom scale, accuracy isn't an issue if it's consistently inaccurate. But during exercise optical HR monitors give the appearance of being a RNG with LED lights, without the advantage of sufficient entropy to be used for cryptography. IOW, kinda useless.