March 3rd, 2002, 07:59 PM
I wouldn't worry about it too much. I've been swimming for many years and aside from my skin drying out in the winter due to dry air, not a big problem. I do shower again before I go to bed because of the chlorine smell which tells me there is a lot of chlorine in my skin. Just don't inhale, especially underwater.
March 5th, 2002, 04:33 PM
Very Active Member
Your comments sound a lot like former Surgeon General Koop. He has riffed on a couple of occaisions about fanciful theories on this chemical or that substance being "harmful" based on slender scientific evidence. The bottom line for him is that we as a society spend alot of time worrying about potentially toxic substances, and spend significant amounts of money trying to remedy their theoretical effects, when he feels the effort and money would be better spent on other health issues with much clearer and more significant impacts (e.g. obeisity, lack of exercise, tobacco use, etc.)
It's a perspective worth considering.
March 6th, 2002, 07:00 PM
Matt quotes Dr. Koop in saying that we as a society tend to get caught up in the small stuff (health-wise), while ignoring the big picture (obesity, smoking, etc.).
In general, I agree, but, in the case of the potential for long-term harm by exposure to chloramines, I am frankly surprised by the lack of real data.
Certainly, there are plausible reasons for concern (nicely discussed on Dr. Rushall's website, URL listed previously on this thread.
In addition to adult swimmers (more importantly, actually), there is the issue of young swimmers, many of whom spend up to 4 hours (sometimes more), several to many/most days per week, for 10 or more years, all while they are in a biologically vulnerable growth and development mode.
My interest in the subject was first triggered by the obvious association with asthma (in most cases, not a huge problem). But my interest really went up when I started noticing little bronze plaques, memorializing club swimmers (teenagers) who had died of cancer, affixed to walls and benches at local competition pools. Then a 15 year old girl on one of my two daughter's teams was diagnosed with (and later died from) rhabdomyosarcoma. Then a 12 year old on my other daughter's team was diagnosed with acute leukemia (fortunately now in a chemotherapy-induced complete remission). Then a 19 year old daughter of a good friend (who had been an age group and senior swimmer for 10 years) was diagnosed with a very rare type of ovarian cancer. She suffered multiple recurrences, but is now doing well following extensive surgeries.
So I wondered: Has anyone ever looked at the incidence of childhood cancer in swimmers, compared to similar groups of kids, who are not swimmers? To my surprise, I found that, no, this has never been studied and reported.
How many excess cases of childhood cancer would it take before it was "worth it" to change from chorination to ozonation? 1 per year? 10 per year? 100 per year? How many excess cases are currently attributable to swimming/training intensively in chlorinated pools? Honest people may disagree about the first of the above questions, but I don't see how anyone could disagree that it's not important to answer the 2nd question. Is there any increased risk? What is the magnitude of this increased risk? What would it cost to bring the risk down to acceptable levels?
No one knows. And this is a pity.
- Larry Weisenthal
March 6th, 2002, 07:28 PM
Very Active Member
into the chlorinator with you all !!
Thank you Larry, for a very thoughtful and thought provoking post. I too, am becoming alarmed at the obvious negative impact upon my body by obsessively excessive amounts of chlorine. ( Asthma,sore eyes, itchy skin, allergic reaction, etc.) To repeat myself, IT'S A POISON !!! Bert
March 7th, 2002, 09:26 AM
Thank you for your post Larry. I find it hard to believe that some post graduate student out there couldn't find academic support to do a well designed epidemiological study of this issue. I hope that organizations such as USMS would be willing to help survey members for such a study. Anecdotal tales are poor indicators of trends. It would be nice to have data.
March 7th, 2002, 12:40 PM
Another interesting fact in this would be to look at indoor vs. outdoor pools. Ventalation systems for Natatoriums have long been overlooked, one facility I worked at exceeded the recommendation/requirement on air movement, yet some days the air quality inside was horrible. Obviously most outdoor pools don't have this problem. Fresh air/air movement is a very importatnt factor in reducing chloramine buildup, pbut as I said it is often overlooked. I have seen people who were asthmatic swimming at outdoor pools and they were actually able to get rid of their inhalers, yet it seems indoor pools with bad air may have a tendency to trigger asthma type problems. Ozone disenfection is not without its health risks too, as is Iodine and Bromine disenfection.
March 7th, 2002, 12:51 PM
Wouldn't a study about the long term health effects be an appropriate use of our USMS Endowment Fund money? If I understand correctly, anyone can submit a proposal for USMS funding such a study to the USMS Endowment Fund's Board of Governors. The chairman is Doug Church, firstname.lastname@example.org . Please correct me if I'm wrong in my understanding.
March 12th, 2002, 12:15 PM
It looks like someone is already starting this study. See below:
Dear Swim Coach,
I am an environmental health scientist conducting research on the potential health effects associated with swimming pool chemicals. I am working with the American Chemistry Council, a coalition of companies that includes manufacturers of swimming pool chemicals, to improve the estimation of exposure to swimming pool chemicals. In cooperation with the U.S. Environmental Protection Agency, we have designed a telephone survey for swimming club coaches to obtain information about the amount of time amateur swimmers practice and other information relevant to swimmer's exposures to chemicals. This information may be used in future regulatory decisions about these chemicals.
Your email was provided to us by United States Masters Swimming, as a coach who is knowledgeable about swimmer's practice habits. If you would be willing to participate in the telephone survey, please reply to this email
(address is email@example.com) with your telephone number and typical time of day that you can be reached (include time zone). Please note that the survey is completely confidential, and we will not provide your names or swim club affiliations to either the American Chemistry Council or the Environmental Protection Agency.
Thank you for your help on this important project.
Dr. Richard Reiss
March 18th, 2002, 07:33 PM
other health effects - i.e., miscarriage
I've read some studies recently (and an article in the Washington Post from a month or two ago) linking chlorination byproducts (trihalomethanes, or THMs) to an increased risk of miscarriage in women. I think one study in California found that the risk of miscarriage rose from 7% to 15% among women who were drinking lots of tap water with relatively high THM levels. My question is, what does this mean for those of us who swim in chlorinated pools all the time?? I have seen a lot of information related to asthma and cancer, but does anyone know of any studies regarding miscarriage? It is a little frightening, especially since doctors recommend swimming as a good exercise for pregnant women (likewise for asthma sufferers of course). It may be that the risks are very slight, but this is something I am reluctant to take much risk with.
March 28th, 2002, 05:40 PM
re: other health effects
I too saw the Washington Post article and was concerned by it since I live hear and drink that water. I'm not a chemist but from my understanding it was referring to chlorination byproducts that are the result of the chlorine in water mixing with organic nutrients, e.g. fertilizer runoff in the Potomac River in the summer time. They pump in more chlorine to deal with the contaminants and the byproduct levels can get high. It's seasonal and local and has been implicated in a lawsuit by a group of Virginia women who had miscarriages. I think the chlorine in and of itself was not factor in the miscarriages. So as long as pool water isn't similarly contaminated, it shouldn't be a problem for swimmers.
March 28th, 2002, 06:58 PM
Well, that is just the problem. The chemistry in a pool is a lot more complicated than water with nothing but chlorine ions floating around. As any pool operator will tell you, the more a pool is used the more chlorine must be applied, and the more difficult management of pH and other factors becomes. That is because lots of organic nutrients wash off of body and hair and react with chlorine, making all sorts of nasty stuff. It is these chemicals that Larry referred to in an earlier post, and what I think is most worrisome.
March 28th, 2002, 08:02 PM
I actually work with someone who did her graduate work on THMs in treated water (THMs being the byproducts that Philip mentioned). She studied women's blood THM levels and found that they increased significantly after women took showers (but she assures me this does not mean there is any risk associated with showers!!). So water that is more highly chlorinated (like a pool...) will cause greater increases in THM levels in people exposed to it. These levels do drop after a few hours out of the water. But the THMs are there, but no one seems to know at what level they might become a measurable risk for different health effects. It seems that the acute exposure is what might be linked to miscarriages. I'm sure it is less of a risk than say smoking during pregnancy, but it is easy to get paranoid about all of these little risks adding up when you swim and take 2 showers every day... not to mention drink a lot of tap water!
April 1st, 2002, 07:39 PM
Very Active Member
The primary fertilizer nutrient that Cl2 mixes with is amonia (nitrogen) - and produces Chloramines just like it does when it mixes with the amonia humans deposit in the pool in sweat and urine. All pools have at least some chloramines, some have a LOT. One method of removing chloramines is to "shock" or superchlorinate - ie bring the free active chlorine (FAC) level up high enough to break the bonds in any combined chlorine molecules. Many pool operators are not well versed in how to calculate the correct amount of chlorine to use in superchlorination - they either undershoot and leave most of the chloramines un touched, or overshoot and leave the pool with WAY too high a FAC level.
April 4th, 2002, 08:53 AM
"Scientists concerned about swimming pool chemical"
This is a story from the Environmental News Network today...
LONDON — Scientists warned on Thursday that high levels of a chemical compound found in indoor swimming pools might pose a risk to pregnant women and their unborn babies.
Researchers at Imperial College London said they found levels of trihalomethanes (THMs), a by-product of chlorine, in London swimming pools that were higher than amounts found in tap water which had been associated with health problems.
"There have been some previous studies carried out with tap water where they found some effects like spontaneous abortion, stillbirths, and congenital malformations at lower levels of these byproducts," said Dr. Mark Nieuwenhuijsen, who led the study reported in Occupational and Environmental Medicine.
He added that the by-product levels are relatively high, but scientists do not know what effects THMs in swimming pools might have on pregnant women and unborn babies.
THMs are formed when chlorine, which is added to swimming pools to keep them clean, reacts with organic matter such as skin or hair.
Nieuwenhuijsen said more information is needed about THMs, which can be swallowed or inhaled, and their impact on pregnant women. In the meantime efforts should be made to reduce the levels, he said.
"The owners of swimming pools have to make sure they reduce the by-product levels because there might be a risk if they stay at this level," Nieuwenhuijsen said.
Chlorine is necessary to disinfectant swimming pools, but the scientists said levels of THMs can be reduced by making sure people clean themselves before swimming. Filtering the water can also help to keep organic matter at low levels.
The scientists examined 44 water samples from eight indoor pools in London and compared the levels of THMs found in the pools and in tap water. Although the amount of THMs varied according to the water temperature and the number of people in the pool, it was higher than levels found in tap water.
April 4th, 2002, 07:17 PM
Very Active Member
Let's not get carried away with overestimated the "threat" of combined chlorine. (And uncritically accepting the pronouncements of web sites without considering the credibility of the source is an easy way to work yourself into hysteria.)
What is the risk of combined chlorine? Unknown. What is the risk of a sedentary lifestyle? Pretty significant. In addition to the legion of studies showing how unhealthy a lack of regular exercise can be, a recent, widely publicized study seemed to indicate it was more dangerous than obeisity or smoking. What are the risks of other forms of exercise? They have their problems too.
My point is that you're kidding yourself if you think you can avoid exposure to all toxins and carcinogens. But, as George Burns once said in response to the questions, "how does it feel to be over 90," that's not bad, considering the alternative.
April 4th, 2002, 07:32 PM
It also doesn't hurt to encourage showering before swimming, filter pool water, ensure adequate air circulation, or using the best water purification system available.
It also does not hurt to provide motivations for doing so, or to swim in the pool that is best maintained. I have, in the past, complained to the pool manager, avoided pools that I thought were poorly maintained, and swum outdoors, rather than indoors, if possible.
April 4th, 2002, 08:40 PM
Matt S. I completely agree with you. Most of us have much more exposure to greater risks in our everyday lives. Second hand smoke I am sure is much worse. But I haven't seen much research on the acute effects of THMs and I would like to see some. I used to work for the EPA and I know how many things are out there in our air and water that are not even regulated simply because we don't know enough about them. I'm not paranoid, I swim every day and even drink tap water occassionally, but I think anything that *might* cause an increased risk of miscarriage is a very scary thought to women trying to conceive. Won't stop me from swimming though... better yet, another good argument for open water swimming...
January 7th, 2004, 08:09 PM
Indoor air quality [IAQ]
This is an old thread. Does anyone know of any new studies
re: asthma and swimmers..esp. kids??
March 15th, 2004, 10:07 AM
In regards to chlorine.
I recently read that chlorine kills the bacteria in your body- healthy and unheathly. The article even states that chlorine in your shower is a culprit which must be much less than the pool chlorine level.
I wonder what any swimming doctors think about this.
March 15th, 2004, 03:54 PM
Very Active Member
Emmett, here is the formula used by CPO's:
Total Available Chlorine(TAC) - Free Available Chlorine(FAC) = Combined Available Chlorine(CAC) (Also known as Chloramines, Chloramines are the nasty smellers when you walk into a facility) Multiply this number X 10 = Adjustment(Amount needed to reach Breakpoint) This number is then put into a formula to tell you how much chlorine to add to the water to reach the breakpoint. These numbers differ depending on what type of chlorine you're using and how much water you're treating. If any one wants the rest of the formula, let me know.
By the way, I am also one of those CPO's that swim in his own pool. Try to keep it as straight as possible!