Indoor swimming pools are valuable assets for any community. They provide recreation and fitness opportunities year round, especially where cold weather makes outdoor swimming impossible. Warm water is beneficial for older and young pool users, as are the whirlpool spas and shallow child pools sometimes featured in indoor aquatics facilities. But, lurking beneath those calm waters are hidden dangers.
Chemical treatments keep indoor swimming pools safe from many communicable diseases. Untreated pool waters rapidly deteriorate into toxic environments, so careful maintenance and frequent testing is important. According to the Centers for Disease Control and Prevention, chlorine is the most common disinfectant used in indoor pool facilities. It reacts upon contact with contaminants such as urine, bacteria and viruses. When the numbers of swimmers increase, the strains put on the disinfection capabilities also increases. Failure to properly sanitize or balance pool waters might result in illnesses such as E. coli and Guardia, according to the CDC. Any facility that encourages large groups of people to congregate might encourage the spread of communicable diseases, particularly during flu season.
Acccording to Dr. Mary Pohlman, assistant professor of clinical medicine at Southern Illinois University School of Medicine and a member of the United States Masters Swimming Sports Medicine Committee, in a May 2010 article for Swimmer Magazine, the byproducts from pool disinfection cause health problems for some swimmers. Chlorine is an odorless gas, but the chloramine compounds resulting from its interaction with ammonia or organic contaminants have the strong odor typically associated with chlorinated pools. In addition, certain chloramines such as dichloramine result in irritated eyes and nasal passages. Trichloramines and trihalomethanes form when the contaminant levels continue to rise in the pool. Swimmers report asthmatic reactions to the chemicals, and wheezing or coughing is common. Indoor pools are especially susceptible to the buildup of irritating chemicals in the atmosphere. Poor ventilation results in vapors trapped inside the pool structure, further degrading air quality. Even the best ventilation cannot make up for the lack of UV radiation from sunlight available to outdoor pools. The CDC says that UV rays help break up some of the byproducts of the disinfection process, so some indoor pools utilize special UV ultraviolet light or ozone treatment in addition to chlorine disinfection to improve water and air quality.
Lightning is another danger associated with indoor swimming pools, a fact that surprises some pool patrons. According to the National Lightning Safety Institute, about 22 million ground-to-cloud lightning flashes occur each year in the United States. Low-resistance conductors such as plumbing or gas lines can introduce nearby lightning into the interior of indoor pool buildings. People who are in simultaneous contact with water and any metal surface are at risk of severe injury. The National Lightning Safety Institute recommends that whenever lightening is within 6 to 8 miles of an indoor facility, pool managers should evacuate patrons to dry, safe areas within the building and bar anyone outside from entering the facility. No one should re-enter the water until at least 30 minutes after the last lightning strike in the area.
Exotic bacteria and chance lightening strikes aside, swimming in an indoor pool carries more pedestrian dangers. Know the depth of the water before you dive. Diving into shallow waters is hazardous for the inexperienced swimmer and only a little less so, for the expert. Remember the basic rule of no running around the pool to lessen the chances of slipping on the wet surface.
- USMS Swimmer: The Healthy Swimmer: Coping With Chlorine Reactions
- National Lightning Safety Institute: Lightning and Aquatics Safety: A Cautionary Perspective for Indoor Pools
- Environmental Health Perspectives: Childhood Asthma and Environmental Exposures at Swimming Pools: State of the Science and Research Recommendations
- CDC: Your Disinfection Team--Chlorine and pH
- Siemens: Swimming Pool Disinfection Techniques & Pitfalls