Can Urinating In The Pool Affect Your Swimming Performance?

Courtesy: Ryan Choong

Water can host a multitude of harmful germs such as E. coli, Hepatitis A, Giardia, and Cryptosporidium, all of which can be killed by chlorine within minutes [1]. Although chlorine can save lives, it can also harm the human body.

A popular saying among swimmers is, “Chlorine is my perfume,” showing chlorine is integral to every swimmer’s life. However, this is misleading; the signature smell of “chlorine” in pools is not chlorine; it is the trichloramine particles resulting from chlorine binding with urine and sweat wafting through the air. As chlorinated pool water is disturbed during swim sessions, trichloramine particles can be released into the air, irritating the respiratory system.

This phenomenon—sometimes called “chlorine cough”—is especially common in indoor swimming pools, where ventilation is limited [2]. Poor airflow combined with intense workouts can lead to short- and long-term effects on swimmers’ lung function, potentially hindering performance. These studies beg the question: should one avoid urinating in the pool for optimal swimming performance?

Why are trichloramines bad for a swimmer’s lungs? There are three types of chloramines, and they originate from combining chlorine to nitrogen-carrying compounds like ammonia and urea, which come from urine and sweat [3]. Trichloramine is the most volatile type of chloramine, and can quickly travel from the water into the air. Trichloramines can build up in indoor pool areas when there is a lack of proper ventilation, leading to irritation in the respiratory system. Furthermore, trichloramine particles are denser than air, so they sink to the lowest point: the water’s surface, where most swimmers breathe [4]. As a result of heavy breathing after swimming, and the build-up of trichloramine particles at the surface of the water, these particles are inhaled in high concentrations causing irritation to the respiratory system.

How do trichloramine particles affect athletic performance? A peer-reviewed study by Swinarew et al. examined 16 male competitive swimmers. Researchers collected breath samples before, right after, and two hours after training. They found noticeable changes in the composition of exhaled air over time, suggesting chlorine exposure in indoor pools affects the lungs and airway lining. This exposure can cause irritation and inflammation, potentially leading to long-term health issues for swimmers [5].

One of these long-term health issues is occupational asthma. Thickett et al. studied two lifeguards and one swimming teacher working in three indoor pools to assess occupational asthma and its correlation with trichloramine particles. Thickett et al. found that trichloramine particles were a cause of occupational asthma and short-term respiratory symptoms such as sneezing, breathing difficulty, coughing, wheezing, chest tightness, and chest congestion [6].

This is supported by a study by Nemery et al., claiming that although swimming can help asthma, it can also trigger bronchial hyperresponsiveness due to exposure to trichloramine particles. This study also suggests that frequently swimming in chlorinated pools can be linked to lung damage and a rise in asthma in children [7]. These respiratory symptoms can significantly limit a swimmer’s endurance and performance in the short- and long-term.

So, does urinating in the pool impact swimming performance? The answer is yes. After reviewing these studies, it is clear that a build-up of chlorine and body waste byproducts is dangerous for swimmers’ respiratory systems and can subsequently hinder athletic performance. However, chlorine can benefit swimming pools as it kills harmful microbes. The best way to avoid these risks is to limit the body waste that interacts with chlorine, and one can do this by avoiding urinating in the pool.

REFERENCES

• [1] CDC. “Home Pool and Hot Tub Water Treatment and Testing.” Healthy Swimming, 10 May 2024, www.cdc.gov/healthy-swimming/about/home-pool-and-hot-tub-water-treatment-and-testing.html.
• [2] Elham Ahmadpour & Maximilien Debia (2024) Estimating airborne trichloramine levels in indoor swimming pools using the well-mixed box model, Journal of Occupational and Environmental Hygiene, 21:6, 397-408, DOI: 10.1080/15459624.2024.2327370
• [3] Nemery, B., et al. “Indoor Swimming Pools, Water Chlorination and Respiratory Health.” European Respiratory Journal, vol. 19, no. 5, 1 May 2002, pp. 790–793, https://doi.org/10.1183/09031936.02.00308602. Accessed 22 Feb. 2020.
• [4] “Are Indoor Pools Causing Chlorine Cough?” Cleveland Clinic, health.clevelandclinic.org/is-the-chlorine-in-indoor-swimming-pools-hard-on-your-lungs.
• [5] Swinarew, Andrzej S., et al. “The Influence of Chlorine in Indoor Swimming Pools on the Composition of Breathing Phase of Professional Swimmers.” Respiratory Research, vol. 21, no. 1, 15 Apr. 2020, https://doi.org/10.1186/s12931-020-01350-y.
• [6] Thickett, K M., et al. “Occupational Asthma Caused by Chloramines in Indoor Swimming-pool Air.” European Respiratory Journal, vol. 19, no. 5, 2002, pp. 827-832, https://doi.org/10.1183/09031936.02.00232802. Accessed 2 Apr. 2025.
• [7] Hoyle, Gary W., and Erik R. Svendsen. “Persistent Effects of Chlorine Inhalation on Respiratory Health.” The New York Academy of Sciences, vol. 1378, no. 1, 2015, pp. 33-40, https://doi.org/10.1111/nyas.13139. Accessed 2 Apr. 2025.