can't we have something like those fitness bands to be worn by children while in the pool - once a person starts drowning the heartbeat and other lifesigns are changing very characteristically and that can just turn the red light on lifeguards console on.
A summer camp I went to when I was younger was very heavily focused on swimming and water craft. We had 3 different colored bands to indicate your swimming ability. Red if you couldn't swim well, yellow if you were OK, but not enough for the deep end and green for the deep end. The counselors tested and trained the kids to go up the color bands, which was pretty neat, but I realize now that it was also a way to keep an eye on weaker swimmers. I think red bands had to have a life jacket on even while in the pool on the shallow end.
There was also the coveted blue band, which you could only get by doing a very rigorous set of tests and passing junior lifeguard training. I had to swim who knows how many laps and tread water for like an hour, plus lift bricks up off the pool floor and various other lifeguard-related things. The blue bands were super "rare" and I realize now it was just an inventive way to encourage the kids to swim better and harder.
Not exactly the same bands you were talking about, but a cheaper alternative and a good way to keep control and prevent drownings before they happen.
I would have been a blue band in your system. My parents moved to Cornwall when I was child, surrounded on 3 sides by water, I gained my surf lifesaving certificate, I was a good swimmer.
Almost two decades passes. I'm in Bali, on a deserted beach with my ex because we "don't want the average experience" or whatever. A small argument and I decide I want a swim. I walk out through the surf, my mind overcome with thoughts of the pathetic argument. I don't think about the undulating sand beneath my feet, but I should. Not even 2 minutes into my swim and I'm out a good 200m. I've swam 10km before in the sea, I'm fit enough, but I had been in a bicycle accident and fractured my dominant arm just 8 weeks prior. My natural confidence, my training, my accolades had resulted in my taking an unknown sea for granted. I looked to the sure, my girlfriend had vanished, no doubt going to lick her wounds from our previous verbal exchange.
I can honestly say the human mind is a strange thing under pressure. I thought back to being 12 and outright laughing at the tourists (emits, slang for ants in Cornish) who died every year often through a mix of alcohol and poor planning. The realisation of such past hubris was overwhelming. I also realised that the people I knew from there would be laughing at my death. I was now well over 1km from shore. My mind kicked in properly, I started swimming hard normal to the rip tide. After 5 minutes of treading water and thinking hard some rocks where looking achievable, so I decided to give it all in the hope of getting there, a fast sprint was my plan and thankfully this worked.
If ever I thought I'd given 100% to a physical activity before I was mistaken. My legs bore the brunt of this assault, my upper-body was uncoordinated due to the cycling injury. My watch was telling me I had been hard going for barely 10 minutes. I was not even half the way, my fear I think allowed for adrenaline to kick in, I was at this point making peace with death of drowning, as an asthmatic a death that has always scared me.
I made it to the rocks and to my joy I didn't need to climb along them, the rip tide was no more. I made it to shore. A half hour swim that had been like no other I've ever had and I hope will ever have. I was so upset with my ex for leaving me. Not watching nor caring as I had asked and she agreed. Going into the unknown water without someone aware is folly and I thought she would be observing me. Anger and most likely just bordem resulted in her not doing so.
TLDR: I was a good swimmer, I still so very nearly killed myself. Knowing when someone is in trouble requires education.
Yes, that's what they meant. Rip tides aren't usually that wide. The best thing to do if you get caught in one is to remain calm and swim perpendicular to the current.
The real shame is you went on a beautiful vacation and ended up in an argument with your spouse. I hope you don't resent your spouse for getting up and leaving, especially since you put yourself in the position to swim while not mindful of your environment.
Also, a back-float is always generally a good strategy in salt water conditions when you've lost control or strength to swim. You carry over common waves and it takes very little energy.
Yeah, I'm having a hard time seeing how laying on your back to catch your breath is a bad idea. I thought everybody did that when swimming for extended periods of time.
The parent does mention swimming against a rip current, which would explain the need to swim at maximum physical exertion for an extended period of time. In that case I don't think he panicked.
My local YMCA branch does the same thing, all minors are required to have a red, yellow or green breakaway necklace that indicate swimming level - kids with red bands cannot be in anything but the 1'6" kiddie pool without an adult within arms reach (parents still have to be supervising regardless), kids with yellow bands cannot go in the deep end of the pool but can be in the shallow end alone.
It's a really smart idea, and while even an excellent swimmer can become fatigued the more experienced ones will be less likely to need aid than the less experienced ones.
Unfortunately that type would not work in a pool... they barely work with significant movement, never mind when there's water sloshing in and out between the LEDs / light sensors.
Costwise, I think that would be in the ball-park, if we can figure out what to monitor, and how, it could most likely be manufactured for <$10.
I do work in this field (wireless vital signs monitoring) and unfortunately I don't know of any current technology that I would trust to monitor heart rate on a swimmer other than perhaps a chest strap (but not as a safety device either). For a point of reference, the Apple watch fails to accurately record heart rate when very sweaty or experiencing periodic movement (such as the periodic arm waving).
There was a kickstarter project for a swim safety device (mentioned by others in this thread) but I believe that was based around picking up the arm movement characteristic of this response, which may be a sensible approach (I don't know enough about the characteristic motions of the drowning response vs regular splashing).
just googled more :) - https://en.wikipedia.org/wiki/Pulse_oximetry - an adapted for waterpool conditions earlobe oximeter is probably what is needed here (with probably a transmitter/amplifier with battery in the wristband). But currently it is in the $100+ territory.
It's not that simple unfortunately. One concern I have is that the oscillatory motion of the drowning response is well within the range of cardiac rates (1-3Hz from the video). Pulse oximetry data is quite noisy and is especially affected by motion affecting the sensing apparatus. Pulse Oximeters employ algorithms to attempt to reject noise (including noise from motion). Unfortunately these algorithms tend to depend on the cyclical nature of the heartbeat signal (using FFT or auto-correlation to latch onto the heartbeat signal, for example). The presence of an oscillatory confounding signal (noise induced from the motion of the drowning subject) would significantly reduce the reliability of these algorithms.
A device for alerting for a drowning subject would be classified as a medical device (in Europe most likely class IIb as it is measuring a vital function in a life support scenario) as the malfunction of the device could fail to prevent the saving of a life. The burden of certification of such a device is understandably high, and one would have to be able to demonstrate that the device can accurately and reliably measure in its intended use and show that any risk that it doesn't has been adequately reduced (I'm simplifying greatly).
Unfortunately it's basically impossible to test, after all how would one get ethical approval for exposing subjects to conditions of near-drowning, so one would be dependent on placing prototype devices on swimmers and catching episodes of near-drowning by chance. It would take a considerable length of time to gather sufficient data to confirm the reliability of the device under such conditions, obviously...
(and no, I would not consider it appropriate to test the device under general swimming conditions as these would not adequately predict performance under drowning conditions).
In terms of cost, an earlobe pulse oximeter doesn't have to be more expensive than a fingertip one (aside from some miniaturisation costs perhaps) but part of the costs of these devices is due to patent issues: http://www.law360.com/articles/106524/philips-accuses-pulse-...
That might be too expensive to hand out to everyone at the pool, but if it were workable for this application it would definitely be in range for something to sell directly to parents.
It wouldn't be able to interface with a device the lifeguard has in this case, but it could surely start making noise and/or flashing in an emergency.
> just hold your breath for couple minutes (or even better - ask somebody physically stronger to "help" you to keep the plastic bag over you head to make sure that you make the time :) and i think you'll learn the difference.
That could easily kill someone, this is totally crazy advice.
It could? I mean it's obviously a terrible idea, but how is forcing someone to hold a full breath for two minutes going to cause them actual major harm? Can oxygen levels actually drop dangerously low that fast? People can hold their breath for that long with barely any setup or practice. Plus having a plastic bag to breathe in and out of should remove a lot of the discomfort and panic since mechanically you're still breathing.
Again, not saying it's a good idea, but the idea that it would kill someone suggests that I'm missing something I should know.
Very similar to blackout. [0] Depriving the brain of oxygen, in general, is a terrible idea and yes it can kill you.
Regardless if it is in a semi-controlled setting and if the intent isn't to continue until you black out but only until you begin breathing in a panic it's still very dangerous. [1]
Well your first link reads like media extrapolating a nationwide trend from next to nothing, and only really talks about the danger of doing it to yourself.
The second link doesn't mention timing except the standard 'five minutes' thing, while holding your breath for two minutes is probably going to lead to somewhere between 60 and 0 seconds of oxygen deprivation.
So I'm still unsure where the risk of dying comes from.
Right, that forces you to reach two minutes, and also makes sure the bag will be removed promptly.
As far as I can tell most of the danger comes from the possibility of having someone hold you still while you panic, and that is not what I generally consider deadly.
> Right, that forces you to reach two minutes, and also makes sure the bag will be removed promptly.
No, it does not make sure of that, besides it said 'a couple' and not 'two' (depending on the person two might very well be enough to harm them, but some might interpret 'a couple' as being even more than two).
The person was suggested to be there to make sure you can't remove the bag yourself and by the time the bag is finally removed it may simply be too late.
"Any activity that deprives the brain of oxygen has the potential to cause moderate to severe brain cell death leading to permanent loss of neurological function ranging from difficulty in concentration or loss of short term memory capacity through severe, lifelong mental disability to death."
Suggesting people do this is highly irresponsible, this is probably the dumbest sub-thread I've seen on HN in all the time that I've been here, which is especially annoying because the main thread is one of the best.
>"Any activity that deprives the brain of oxygen has the potential to cause moderate to severe brain cell death leading to permanent loss of neurological function ranging from difficulty in concentration or loss of short term memory capacity through severe, lifelong mental disability to death."
That cites source 12, which doesn't seem to support the critical "any activity" part of the sentence, at least in terms of how long the oxygen deprivation lasts.
>95.7% of these deaths occurred while the youth was alone
Seems to support my skepticism for a strictly-timed co-operative activity.
I'm not even sure you'd end up in oxygen deprivation at all within a couple minutes when you start with a nice big breath.
I'm sorry you think my question is dumb. I was just hoping to learn something. At this point I'm feeling reasonably confident that I wasn't unaware of important information, and 'dying' was strong hyperbole. I'll note again that I don't support actually doing it.
man, I've put a smile there for a reason... The "help" is brought up as a device to illustrate the difference between at-will fun excitement and against-will panic. No sane person would be forcing another to not breath ( until of course it is a part of the job, ie. like police - chockholding into submission - or military investigators - waterboarding and the like)
Edit: to "mdup" below - i've specifically mentioned "until of course it is a part of the job" above - the major aspect of Milgram experiment was to present to the experiment subjects the shock delivery as a "duty".
One of the most challenging bits with that is going to be transmitting RF underwater. And an interesting thing to think about is whether or not such a device would end up causing even more accidents, when people start just assuming that "it's ok if I go past my limits, someone will save me"
Underwater RF is no trouble in this case. You have the signal backwards. As long as there is no problem, regularly transmit an identity beacon. Loss of signal is the alert.
How does the regular beacon transmit if it's underwater? Someone standing in the shallow end of the pool or treading water in the deep end may pretty easily keep their wrist underwater for minutes at a time.
There's two things that such a device would need to have: quite low false positives (so that the lifeguard isn't distracted by false alarms - leading to a boy-who-cried-wolf scenario), and vanishingly small false negatives (the first time a kid dies because the device didn't work, it'll be a bad day). In-water RF would be very hard to do to make those two conditions true.
Edit: Don't get me wrong, I think it's a fabulous idea. Wearing my EE hat though, I haven't thought of a good way to do it that would work reliably enough for a life-saving device.
That's a fantastic question. This is probably the right place to ask if there is pattern that can be detected from the wrist. It also makes sense to line the pool edge with lights that can change color, so the bracelet distinctively lights up the grid square of the pool where the drowning is happening, alerting the lifeguard or a strong swimmer nearby.
That would probably cause a good deal of false alarms though.. people that aren't comfortable in water will have elevated heart rates every so often over normal stuff.
>"I wonder where you get/how you generate a dataset of the vital signs of drowning children..."
panic attack data set will get you halfway there and panic attacks happen naturally and sufficiently frequently. Add the dataset from something like asthma attacks (unfortunately it is easy to obtain too).
