Swimming in a pool relies heavily on maintaining a careful balance of water chemistry. Chlorine is necessary to sanitize the water and kill harmful pathogens. The challenge arises when pool chemistry is mismanaged, leading to an excess of chemicals that can turn a refreshing dip into an irritating experience. A strong, pungent chemical odor is the first indication that the water is unbalanced and potentially harmful.
Understanding the Source of Irritation
The irritants swimmers notice are usually not free chlorine itself, but chemical byproducts called chloramines, also known as combined chlorine. Free chlorine is the active disinfectant, but when it reacts with organic matter—such as sweat, urine, and body oils—it forms chloramines. These combined chlorine compounds have a distinct, foul odor often mistaken for high chlorine concentration.
High levels of chloramines are the primary cause of eye and respiratory irritation, and they reduce the effectiveness of the free chlorine available to kill germs. When a pool is described as “over-chlorinated,” it often means the chemical reaction has created a high concentration of these gaseous chloramines, especially in indoor spaces where the fumes concentrate.
The pool’s pH level also plays a role in irritation. A balanced pH is needed for chlorine to work efficiently. If the pH is too high or too low, free chlorine is less effective, prompting operators to add more chlorine. This exacerbates the formation of irritating chloramines, leading to a pool that is uncomfortable and poorly sanitized.
Acute Bodily Reactions to Over-Chlorination
The most common and immediate effect of swimming in water with high levels of chloramines is on the eyes. Chloramines wash away the tear film, the protective layer that keeps eyes moist and clear. This loss of lubrication causes stinging, redness, burning, and watery eyes. Minor visual disturbances, such as blurred vision, can also occur, but eye irritation usually resolves within 24 hours.
The skin is also susceptible to irritation from excessive chlorine and chloramines, which act as drying agents by stripping the skin of its natural oils. This action erodes the skin’s protective barrier, leading to dryness, itchiness, and irritant dermatitis. Individuals with pre-existing conditions, such as eczema, may find that exposure triggers or worsens their flare-ups. The longer the chemicals remain on the skin after swimming, the more pronounced the irritation.
Respiratory systems are vulnerable to the gaseous chloramines that off-gas from the water’s surface, especially in poorly ventilated indoor pools. Inhaling these vapors can irritate the nose, throat, and lungs, leading to symptoms such as coughing, wheezing, and chest tightness. This irritation is sometimes referred to as “chlorine cough” and can be a trigger for individuals who have asthma. In rare, high-exposure scenarios, inhaling concentrated chlorine gas can lead to serious symptoms, including fluid buildup in the lungs, which requires immediate medical attention.
Immediate Response and Recovery
If you experience irritation after swimming, the most immediate step is to rinse your body thoroughly with clean water, preferably by showering. This washes away residual chlorine and chloramines clinging to the skin. For irritated eyes, flushing them with generous amounts of clean, lukewarm water for at least 15 minutes is the recommended first aid protocol.
After showering and drying the skin, applying a fragrance-free moisturizer or cream helps restore the skin’s protective barrier and alleviate dryness and itching. Some swimmers find relief by using a vitamin C solution, which neutralizes chlorine on the skin, as a post-swim rinse. For mild respiratory symptoms like a cough or burning throat, moving to a well-ventilated area with fresh air is typically sufficient.
Seek professional medical attention if symptoms are severe or persistent, including difficulty breathing, a persistent cough lasting more than a few hours, or a severe skin reaction. Consulting a doctor is also necessary if you experience symptoms like vomiting, severe eye pain, or signs of tissue damage, as the effects of chlorine exposure can sometimes worsen over a period of days.