Urine, Not Chlorine, Causes Red Eyes in Pools (2015) | Hacker News Reader

Urine, Not Chlorine, Causes Red Eyes in Pools (2015)

smithsonianmag.com

118 pointsbriantailor93 comments

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"Luckily, there are several easy ways to prevent things from tainting your poolside experience forevermore."

Okay...

"Always shower before entering"

Right, but I'm not the one with diarrhoea. I can't get everyone else to always shower.

"stay out of the pool if you’re not feeling well"

By the time you're feeling unwell, isn't it too late already?

"test water frequently if you own your own pool"

Getting your own pool is certainly a great tip. Duly noted. For those of you afraid of pickpockets on public transport - a very easy way of dealing with it would be to get a car. For some reason it makes me think of The Onion :)

Reminds me a bit of Buzzfeed articles like "10 people you thought, were still alive!" with a picture of Keanu Reeves as the article headline image and then, obviously, he's not on the list.

Why do you even bother...

The report comes from the Centers for Disease Control (CDC), not the Centers for Convenient Pool Access!

The focus is going to be on things that someone somewhere can do which are effective at disease prevention. Someone who manages a pool (at, say, a hotel or a park) can change their policy to require showers, for example.

The chlorinates created when the chlorine reacts with e.g. sweat and urine is what causes red eyes and breathing difficulties. From my experience, stay away from hotel/health club pools. These usually have saunas and jacuzzis which means people jump into the pool afterwards and contaminate it a lot... If you are doing swimming for fitness you will be inhaling a much larger volume of air, plus you will be inhaling air near the surface of the water where the chlorinates are most concentrated. Stick to public leisure centres where the pools are designated for fitness swimming. The people using these pools are generally a lot more conscientious about showering before entering the pool.

> The people using these pools are generally a lot more conscientious about showering before entering the pool.

But you’re now going to face swimmer drama. Violation of some unknown, unspoken rule will result in dirty looks and jerky behavior.

I’d rather swim in pee than deal with unfamiliar serious swimmers!

Since you generalized a large group of people, I'm also going to generalize them, too. Most swimmers are very reasonable people just trying to work out. If you ask questions while they're between sets or after their workout, I'm sure they will be willing to talk to you. There are only like 4 rules when swimming.

1) Stay to the right side of the lane. 2) If you're on the wall, stay in the corner of the lane (so people can turn). 3) If someone touches your foot, stop for a second and let them pass. 4) If multiple lanes are open, try to stay with people of similar speed.

If they're getting mad at you for anything else, those people are being jerks. Rule 1,2, and 4 are all things you would do while running or cycling. They are follow the flow and try not to be in the way. They are common courtesy everywhere, not just a pool. Rule 3 is the only one that may not be intuitive, but you'll be kicking someone in the fingertips and face for at least a whole lap if you don't let them pass. Plus, it can ruin a set if they're trying to hit a certain pace. I'm not saying anyone should ever be a jerk to you, but it's similar to when people walk 4 wide down the sidewalk.

I've never swam for exercise in lanes before, but I always assumed you'd only have one person in a lane at a time. How does it work to have two in one lane? If I'm swimming and someone wants to share my lane, do I swim out, wait for them to get to my side, then swim back when they reach my side? (And if I'm the slower person, I assume I start swimming behind them as soon as they launch off from the edge?)

It'd also be a shock to me to see a second person just simply joining me in my lane. Is there a protocol for joining a lane other than, I guess, flagging me down and asking? Do people normally know how to accept having a second person in their lane?

Funny thing to be asking so many questions about...

One person per lane is generally guaranteed only in competition. You can get your own lane if your pool is lightly loaded but by no means would your lane be off limits to others, normally.

It's crowded when you're finger tips to toes or you smash into the oncoming swimmer off the wall (the ones following you) which is typically the mistake of the one turning and not the oncoming swimmer but not always. You try to stick to lanes moving at your preferred pace. It's a little like driving - sometimes you get your own lane and sometimes you don't.

You haz kwestuns we haz anserz

Rule 1, stay to the right. Generally, there is a black line running down the center of the line. Stay to the right of it, it's like traffic. Swim down on the right, reach the wall, turn, turn around swim down on the right again (you're on the opposite side). You don't have to coordinate with anyone. That's why it's courteous to stay to the corner of the lane when you are stopped at a wall.

During peak times, my YMCA wants 5 to a lane. It’s tough because you have competition level swimmers, people who were competitive swimmers and casual swimmers. Some folks are having fun, others are pushing.

Customs vary by when and where you learn them, and it’s feels very hostile, especially for casual swimmers. (In my online experience, the closest thing is the “eternal summer” phenomena in Usenet in olden times)

In any case, worrying about the nonexistent risk of swimming in a recreational pool is counter-productive — casual swimmers will be turned off by the experienced ones.

>the closest thing is the “eternal summer” phenomena in Usenet in olden times

Surely it must be the Eternal September :) [1]

[1]https://en.wikipedia.org/wiki/Eternal_September

I’m eternally grateful you picked that up! :)

1) 2) & 4) are sane, reasonable and common. 3) however is not common at all, in fact I've never come across this behaviour in several years of swimming in multiple places. I just don't see how this would apply if there are not enough lanes for different paces. It does not scale at all. One very fast swimmer could easily dominate a lane, everyone would have to watch out for him/her. When you have more than 4 people on a lane, this is heavily annoying. If everyone applied 4), this wouldn't be a problem at all.

It really depends on context. If you have a bunch of people sharing one lane at a rec center, yes, you could be a huge jerk if you constantly were forcing people to stop by touching their feet. If there is one other person in your lane and there isn't a massive skill gap, touching their feet and having them stop is perfectly reasonable.

I swam in college. I was a distance swimmer. We would have warmups during the break with people from all sorts of different teams at different skill levels doing different events. When I'm warming up for the 1650 and there are sprinters in my lane, they are going to touch my feet a lot. That is just part of it. It takes literally a second for them to pass and allows them to do what they need to do. Context is key for sure, but in general feet touching is the international sign of please let me pass in swimming.

How does this work?

Aren't you usually furiously kicking/flapping with your legs when swimming?

Are they actually touching the bottom of your feet, ie your soles? Do they have to time it right to not get kicked?

For freestyle (front crawl), it's more of a scissor kick. Your whole body turns with you so it's really easy to touch the sole of the foot heading toward the bottom of the pool. When someone is doing something like breaststroke, they're doing a frog kick which is generally going out and away from the body and then pulling the legs in, you just time it so you touch their feet when they pull their legs in.

Chloramines, or combined chlorine are the by-products of free chlorine reacting with organic material. If there are too many, the pool has been improperly treated, or a huge amount of organics has overwhelmed the system. Chlorinates are things into which you've added or introduced chlorine.

Thanks for this clarification, my knowledge of chemistry is quite poor. I remember the pool manager trying to tell me that 'if anything, the chlorine levels are low'. I suspect this was because any chlorine they added was very rapidly being turned into chloramine by-products.

Yes, that's usually the case. Chlorine is actually pretty odorless until it reacts with something.

When you say difficulty in breathing, do you mean that feeling that you sometimes get after being in a pool for a long time where if you take a deep breath, it kind of hurts your lungs?

I trained briefly in a health club/gym pool (not full length, had a sauna etc). I would usually find that after swimming in it for any length of time, inhaling fully wouldn't feel like it was providing me with the expected amount of oxygen - hard to describe accurately the feeling but it definitely wasn't just breathlessness from exerting myself. Didn't really hurt or anything. When I swam in a proper fitness pool however, there were no feelings like that.

Have you ever been tested for asthma? I used to get that feeling all the time when doing rigorous exercise, and I was always under the impression that it was related to my asthma in some way (I could well be wrong though, I can't remember where I learnt this).

Pool swimming is one of the least likely triggers for exercise-induced asthma. The air above the surface of a pool tends to be warm with very high humidity, which is the ideal air for an asthmatic.

If a person gets that feeling after any exercise, yes, it's not a bad idea to get checked for asthma. But if it only happens after swimming, I would think it much more likely that the issue is related to that pool.

Chlorine allergy is also a possibility, if the person experiences symptoms in pools that don't occur elsewhere.

I remember it happening to me in some public pools but never in the ocean.

I've also done some high intensity training outside of water without the same lung issues. I'll get out of breath after running for a while, but the pool related issue is every time I breathe in deep to expand my lungs, it would feel very strange and hurt. It would last even an hour after leaving the pool area.

Never been tested and generally speaking I rarely suffer from chest issues. I have no problem exerting myself in a well maintained pool (or whilst running or cycling), it was just a particular experience I had in a poorly maintained pool.

That’s the feeling I get after walking or cycling in London traffic and getting a lung full of diesel fumes...

I normally get that feeling when exercising on open trails as well or even indoors. It's part of exercising intensely

Perhaps, but it feels much worse in a polluted environment, and takes much longer to go away (lungs still sore/“tight” hours later).

I do think it’s strange when I see people jogging along polluted arterial roads for this reason. Especially when there are often traffic-free trails or quiet back roads available nearby!

Interesting to hear it is a notable effect, I've never ran in a polluted environment before. Next time I'm in New York I'll have to give it a try.

New York is notably less polluted than many European cities. For one thing, there are far less diesel vehicles. The US has long had stricter and more effective vehicle emissions rules than Europe.

That's the same feeling most humans get when they're exerting themselves in an environment with lots of airborne particulate matter.

Some are more sensitive to chlorine than others. I have astma and feel awful after having been in a pool.

That is why you should shower before going in to the pool. At school we were always required to shower before and after.

One pool I have been at added a shower you have to go through to get to the pool. It's a continues curtain of water.

> One pool I have been at added a shower you have to go through to get to the pool. It's a continues curtain of water.

That's clever, they should install that in more places.

Briefly getting wet isn't a shower though.

A curtain of water isn't going to do much about cryptosporidium.

dunno. seems a lot of wasted water, you can't recirculate it or you'd be back to square one.

maybe if it's activated with a pressure plate of sort it'd be more environmentally friendly.

I've seen things like these a few times and all were motion activated. However in practice they almost always run because of the amount of people.

You can likely set it up to recirculate 99% of the water directly, and sending the other 1% off for treatment. With water circulating that quickly removing a small fraction each circulation should still keep it very clean.

Maybe the water is changed every day. It would still be useful as the large (lets say 2m³) volume of water would slowly begin charging up with contaminants

At that point, you'd need to treat it with chlorine, and it wouldn't be much better than the pool itself. Probably better to just use good greywater recycling techniques for shower waste.

Why do you think it is being wasted?

It isn't being contaminated, and will eventually wind up back in the water supply.

It is definitely being contaminated and won't end up back in the water supply until it's retreated (which is not free).

If it's not washing something off, what's the purpose of it?

Or a motion sensor perhaps?

Slightly off topic, but you should shower to avoid temperature difference too, specially in hot days. I don't know about the lifeguard situation in USA, in Italy it's pretty terrible; it should be absolutely required to have a shower before jumping in the water.

Why are sudden temperature changes bad? When I was a kid in the north of Scotland we'd always jump in as gradual exposure to cold water was miserable - the shock of jumping in was always quite bracing ;-)

Mind you - as I doubt if it was much above 20C most of the time I doubt the temperature difference between air and water was that large!

I think the idea is that a sudden immersion in cold water when the weather is hot can cause a sudden contraction of your blood vessels which can result in a syncope. At least that's what I've always been told, but I know there's a lot of cargo culting and urban myths surrounding these topics so it's hard to know what's really dangerous and what's just superstition. For instance as a kid I've always been told that it was risky to swim just after eating a meal (because of the bloodflow required for digestion or something like that) but as far as I know it's been debunked and doesn't make biological sense.

I find it hard to imagine how a swimming pool could be cold enough in a hot climate for this to be an issue for anyone healthy. If it's hot for more than a couple days, the pool water will start to warm up too.

I've heard of this concern more in the context of much larger bodies of water like the ocean or snow-fed mountain lakes, which can stay cold a lot longer than a pool by virtue of their size (and in the case of the latter, a continuous influx of very cold water).

Syncope == faint(ing)

TIL a new word, https://en.m.wikipedia.org/wiki/Syncope_(medicine)

I actually ended up with this word while attempting to translate the French word "hydrocution" but after some more googling it looks like "cold shock response" is the right term: https://en.wikipedia.org/wiki/Cold_shock_response

The cardiovascular system has to suddenly adjust its rate to keep the body warm enough. If your heart is weak, it may not be up to the task and a heart attack is possible.

It might be fine for young people and people with people with peak cardiovascular health, but for older people or anyone with impaired cardiovascular health, the risk goes up.

Does how you get into the cold water make a difference? Specifically, entering in a way that does not trigger the mammalian diving reflex, such as wading in up to your chest or neck, versus entering in a way that does trigger it, such as holding your breath and jumping completely in?

Yes, because then the body doesn't have to adjust to the new environment in a second but gradually adjust instead.

Now, I'm thinking of all those images of old Russians going in to frozen outdoor pools, AFAIR they always climb down a ladder/steps. This might explain why.

Slowly getting in to cold water is some kind of torture to me, I always dive in. But frigid water is not my thing at all.

I don't know about the lifeguard situation in USA, in Italy it's pretty terrible;

Interesting, because my impression was that there's a decent amount of staff comparing to my country (Poland).

Also it's the first place at which I've seen a line of lifeguards on rafts making sure nobody reaches the point where they can collide with motorboats.

I don't know about the Poland situation, but the main problem in Italian (I guess other lifeguard certs too) it's the lack of any required refresher course. Things are changing fast on first aid practices best practice and a lot of people are behind.

Personal example: I'm 20, I am a certified lifeguard (I did the training because I was a competitive swimmer), no experience but I could extend my certificate till I am 65 year old, in whatever physique condition with whatever knowledge of best practice. That's just plain wrong, and I know that a lot of States work in a really different way with refresher courses and such, making pools and sea a safer place.

Luckily, it's much better in the USA, even though many regulations vary across state and county lines. Where I worked, we needed an in-pool refresher course and test every year, with a pool management course (chemicals, filter, etc) every 2 or 3 years. After getting you American Red Cross CPR certification, you needed to take a short refresher course every year for the next 2 years, after which you'd need to retake the course.

Could you explain the thing about the temperature difference? What's that about?

Also, where do you have lifeguards? Indoors, outdoors? I don't remember seeing any at all here in Sweden.

There are a variety of reasons why it's considered best practice to make people have a shower before entering the pool. They already explained it, talking about elderly people / etc. If it's sunny and you are out of the water from three hours tanning, your heart adjust to a certain frequency. If you jump in with any prior advice to your body into the water, heart has to adjust to a much different frequency, and an heart attack is possible.

The problem here is that a lot of people doesn't know what's going on with their hearth and certainly a lifeguard doesn't know about.

Also, adding to that, https://en.wikipedia.org/wiki/Cold_shock_response

I don't know about Sweden situation, but it seems really weird that no lifeguard was there. In Italy every public or private place with a pool needs a number of lifeguards according to the number of people of the pool / the pool's dimension. It's really easy to have some heart attack or hypoxia going unnoticed, example: X person jump in, simply doesn't get up. Also, time is key, if an heart attack occurs a close defribillator with someone able to use that / a lifeguard able to transport that person out of the pool without damages (it's not that easy as it sounds) can be really important. Drowning situations are even more dangerous, a drowning person can have a force in their arms able to do real damage and everything needs to be deal in the safest way.

The headline is a bit clickbaity. The third paragraph starts with "In fact, chlorine is still a culprit." A more accurate title could be "Urine and Chlorine Cause Red Eyes in Pools."

Actually, it's chloramine alone that is the culprit for both the smell and the red eyes according to the actual report. Which isn't reporting any new finding, as far as I know this has been well known since many years.

The short version is; A pool that smells strongly of 'clorine' ( chloramine(s) ) is a pool with a high load of contaminants, and whether or not the chlorine concentration is kept at levels enough to cope with the load can't afaik easily be determined, but it's reasonable to a assume a higher load implies a higher risk for insufficient levels.

Or as the report states: >What you smell are actually chemicals that form when chlorine mixes with pee, poop, sweat, and dirt from swimmers’ bodies. Yuck! >These chemicals—not chlorine—can cause your eyes to get red and sting, make your nose run, and make you cough. >Healthy pools, waterparks, hot tubs, splash pads, and spray parks don’t have a strong chemical smell.

I think it's more accurate as it is. Your alternative suggests to me that both contribute independently i.e. chlorine alone will burn eyes, where the article suggests that isn't true.

Since chlorine in pools is ubiquitous, the urine's the central issue. C.f. hydrogen tanks being labelled "fire hazard", not "fire hazard in an oxygen environment".

Maybe, but it's not only urine that causes red eyes. When chlorine binds with any organic matter it can create compounds that sting your eyes. Sweat isn't as eye-catching as urine.

I don't get it. Chlorinated water from the drinking tap, otherwise perfectly pure, smells of chlorine. And swimming pools might use much more than it's used in public water distribution, and in variable amounts- depending on how many tablets have been used, how recently, etc.

I worked at a pool as a lifeguard instructor throughout high school and college. The aquatics director used to try to explain this to people who would blame her for misbalanced chemicals when there was a strong chlorine smell. It would always get so much worse as soon as the pool got busy, like during a swim class or children’s swim lessons. Getting people to shower before entering the pool was a hopeless plight.

There is a very informative video[1] that also links to scientific papers about this phenomenon and concludes much less sensationally.

Essentially, urine is a sterile substance containing %95 pure water and no living cells or bacteria. Other than the asthma inducing effects of chloramine, swimming at a public pool doesn't pose a massive threat to your health.

[1]: https://www.youtube.com/watch?v=S32y9aYEzzo

While that may be the case for urine, the article pretty clearly states that fecal matter is a significant risk factor.

I was under the impression that the sterility of urine was a myth.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3957746/

https://www.europeanurology.com/article/S0302-2838(15)00206-...

People would take their infant children swimming in "swimmies" (diapers) at an apartment complex pool I used to often get ear and eye infections from using. Once I learned that's what those children were wearing in the pool I ceased all usage. Never had those problems before or after that particular rental.

Swimming pool I occasionally visit in Prague uses less chlorine and has installed UV lamps in the pipes. The water quality is great. I hope this gets more widespread.

I am there in a few days. May I ask which one?

https://www.hotelolsanka.cz/en/sports/swimming-pool/

I want to stop learning now.

I helped maintain a large public pool a few years back, and I saw first hand how disgusting they could be. I now swim almost exclusively in creeks and rivers.

And hope there isn't a school trip up stream...

Or a dairy farm, or a beaver dam or...

I always consider what is upstream. Same when I fish.

>Actually, according to CDC healthy swimming spokesperson and epidemiologist Michele Hlavsa, it’s poop. She tells LiveScience’s Rachael Rettner that people with diarrhea can spread a filter and chorine-resistant Cryptosporidium, a parasite that is the leading cause of waterborne disease.

I love swimming and this article has just disturbed me so much, I'm not sure I'll be going to the swimming pool in the near future.

My wife had an attack of cryptosporidium a few years back that the doctor said was almost certainly from a swimming pool - very unpleasant bug.

Was it covered or outdoors? The wiki says it can be deactivated using low doses of UV, I wonder if being exposed to the sun is enough.

Indoors - a public one that was close to end of life.

Are there companies doing wastewater monitoring on pools for public health?

All kinds of disgusting things get flushed down toilets in homes and businesses. I think that monitoring a swimming pool would give more helpful data, because the bacteria/viruses/pollutants were all carried by humans.

Working for a water treatment company here. We have created a mathematical model for public pools that includes a projected number of visitors per weekday, the weather forecast, school holidays, and based on that, a daily influx of urine, feces, pus and so on. We use this model to create adaptive controllers that minimize the amount of chemicals used to keep the water safe while actually keeping it safe (work in progress).

Working for this company taught me stuff I really didn't want to know about...

Now you just need to correlate your model with the stock market and use Twitter for sentiment analysis.

That just killed my swimming sessions. Thanks HN!

I hadn’t been to a public pool in years (we have our own) until the other week and had forgotten what it smelled/tasted like.

The smell/taste of public pool water is definitely mostly urine, chlorine does not smell like that.

How feasible is that mythical pool pee dye?

I suppose an indicator dye that responds to chloramines could be developed, but the real challenge would be to make it safe and cheap enough not to be counter-productive.

This title makes my eyes red.

I think I’ll just stay out of the pool

just wear goggles, ear plugs and use a snorkel

Aren't the pools supposed to be sanitized everyday? And shouldn't it be shut down if it's not properly maintained?

What kind of maintenance do you propose is going to prevent people from micturating and defecating into the water?

Well this is.... unfortunate.

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