I am 47years old and have returned to swimming as a fitness choice. I get 3 workouts of 2500yds/week and feel great. I also have an inground pool that my family enjoys in the summer months. My question relates to the long term consequences of chlorine exposure. Do studies exist that show whether swimmers have an increased health risk to cancers? Has anyone looked at pool chlorine exposure as a health risk in any way? The pools I swim in all use chlorine as a sanitizer and I would hate to think my exercise regimen may be doing me more harm than good!
Former 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.
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.
Matt
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.
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...
www.enn.com/.../reu_46850.asp
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.
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!:D
If you think a lap pool is scary - then you don't want to know about your jacuzzi/hot tubs.
If the pool you swim at has an ozone system then you don't have to worry so much about chloramines (not only does the ozone disenfect but it also breaks down/destroys chloramines).
Lastly for indoor pools your HVAC system is very importatnt - hopefully the air circulation system isn't at the bottom of the required scale (more air movement is better).
Ok a swimming doctor (family practitioner, not a super sub specialist or toxicologist)
I read over all the posts and searched some sites (like the CDC and FDA etc) for research on this.
Everything really focuses on chlorine gas as a respiratory irritant, with little research on long term, low level exposure. If you have asthma, this may cause you problems. However, let your doctor know and most likely your medicines can be adjusted to help prevent any asthma complications associated.
Some important things to remember. Chlorine is very reactive. It sure does cause some damage, but only very quickly and locally. Your body actually USES its own natural chloride ions in specific places to help manage things like mucous (especially in the respiratory system). There are 3 main sites I can think of that chlorine the swimming pools could theoretically cause some problems.
First is the eyes. Obvious: wear your goggles.
Next is the surface area of your body. Hair: makes it tougher, strawlike and funky. Use a conditioner or something like that to remove and or block chlorine; also a swim cap. Your skin can definitely be affected, but because of the cool way our skin is put together, it really should not be able to penetrate the skin and cause any damage internally. Thus, you CANNOT kill any beneficial bacteria internally this way. You can (and will) get a local skin irritation depending on length of time in the pool, other existing skin conditions (like eczema), etc. These can be minimized or prevented by showering before getting in the water (then the little microscopic areas of your skin are full of water with less chlorine than the pool already) and using a mild lotion after (not before, it will strip clean off) getting out of the water. Shower again, however, to replace the chlorinated water before lotion.
Sorry for the length of this.
Next is respiratory. I could not find any data on long term exposure to low level chlorine levels. However, there could in theory be a chance of causing damage to some of the supporting structure of the alveoli. I must hasten to add that one of the reasons I started swimming for fitness is that the healthiest old folks I see as patients are over represented as swimmers. These are 80+ year olds whose lungs sound awesome. So weak anecdotal evidence: I doubt it is a worry.
Finally (oops I lied I came up with 4 sites) is accidental swallowing. This would be my guess as to where the funky organic chlorine molecules came from in the study cited above. Ironically enough, chlorine itself would be unlikely to cause much problem in the stomach, and is going to get neutralized as soon as it hits the small intestine anyway. However, weird organic chlorine compounds could in theory survive some digestion. Don't think about this too much or you'll be scared to get any water in your mouth next time.
Oh yeah: cancer is unlikely a risk (although never impossible), because cancers really need to come from DNA damage, and chlorine has usually already reacted to your cell membranes, epidermis, etc and "burned itself out" before it could get close to your DNA. BUT: I couldn't find much research on this, so this is largely supposition.
Summary: Swimming is great and overall probably better for you than any other exercise, even when chlorine is involved. My opinion.
