Nosebleeds during or after swimming almost always trace back to a combination of chemical irritation, temperature change, and dry or fragile blood vessels in the nose. Preventing them comes down to shielding that vulnerable tissue before you get in the water and caring for it after you get out. A few simple habits, like applying a thin layer of petroleum jelly inside your nostrils or wearing a nose clip, can make a real difference. But the best approach depends on why swimming triggers your nosebleeds in the first place.
Why Swimming Causes Nosebleeds
Most nosebleeds originate from a small patch of tissue on the front of the nasal septum, the wall dividing your two nostrils. This area is sometimes called Little’s area or the Kiesselbach plexus, and it contains a dense web of tiny blood vessels sitting very close to the surface.1PubMed Central. Kiesselbach Plexus Because those vessels are so superficial and the overlying tissue is thin, even mild irritation or drying can crack it open and start a bleed. Children are especially prone because their nasal lining is thinner still, and they tend to touch or rub their noses more often.
Swimming creates a perfect storm for this fragile area. Chlorinated pool water, cold temperatures, and pressure changes from diving or flip turns all stress the nasal lining in slightly different ways. Understanding each trigger helps you choose the right countermeasure.
How Chlorine Irritates the Nasal Lining
The disinfectant in most pools is some form of chlorine, typically sodium hypochlorite or a compound that releases hypochlorous acid in water. These chemicals are effective at killing bacteria, but they are also corrosive to mucous membranes on contact.2Clinical Toxicology. The Clinical Toxicology of Sodium Hypochlorite When chlorinated water enters the nose during a breath or a turn, it strips away some of the protective mucus coating and dries out the tissue underneath. Over time, repeated exposure thins the lining and makes those tiny blood vessels more vulnerable to rupture.
Research on indoor pool workers, who spend hours in chlorinated environments daily, shows measurable changes in nasal tissue compared with people who don’t work around pools. Pool workers had significantly more epithelial cell shedding and higher counts of certain inflammatory cells in their nasal passages.3PubMed. Effects of Indoor Swimming Pools on the Nasal Cytology of Pool Workers If spending time near the water does this, putting your face in it amplifies the effect. Swimmers who train several days a week accumulate chlorine exposure quickly, and their nasal lining may never fully recover between sessions.
Indoor pools often present a bigger problem than outdoor ones, because the chlorine byproducts (chloramines) hover just above the water’s surface in the enclosed air. You breathe them in even between laps. Outdoor pools have better ventilation, which disperses those irritant gases. If you have a choice, swimming outdoors may reduce the chemical assault on your nose.
Cold Water and Temperature Shifts
Temperature changes also affect how your nasal lining behaves. When your body cools down, the mucosa inside your nose tends to swell as blood flow increases to warm incoming air. When you heat up, the opposite happens and the tissue shrinks.4PubMed. Nasal Reaction to Changes in Whole Body Temperature Jumping into a cold pool triggers that swelling response, which can engorge the already delicate blood vessels in Little’s area and make them easier to rupture from minor contact or pressure. Then, when you get out and warm up, the rapid shrinkage can crack tissue that swelled beyond its elastic capacity.
This back-and-forth explains why some swimmers get nosebleeds not during the swim itself but in the shower afterward or while toweling off. The temperature swing from cool pool water to a hot shower is especially abrupt, and that shift can be enough to pop a fragile vessel. Easing into temperature changes, for example rinsing your face with lukewarm water before stepping into a hot shower, can reduce the shock to your nasal tissue.
The Case for Nose Clips
Nose clips are the most direct prevention strategy because they physically stop pool water from entering your nasal passages. They’re standard equipment for synchronized swimming and are common among competitive backstrokers, but recreational swimmers often overlook them. If chlorine is the main trigger for your nosebleeds, a nose clip removes most of the chemical contact.
There is research support for this approach beyond the obvious logic. A study of competitive swimmers found that rhinitis, both allergic and non-allergic, is common in the sport, and that chlorine exposure plays a significant role in driving the inflammation. Among swimmers with non-allergic, neutrophil-driven nasal inflammation, using a nose clip reduced the inflammatory cell infiltration in their nasal passages and lowered nasal resistance. Swimmers with allergic rhinitis also reported clinical improvement with nose clips, though the cellular changes were less dramatic.5British Journal of Sports Medicine. Allergic and Non-Allergic Rhinitis in Swimmers: Clinical and Cytological Aspects Less inflammation means a healthier, more resilient nasal lining, which translates to fewer bleeds.
The main downside is comfort. Nose clips can feel pinchy and awkward, especially during distance swims, and they force you to breathe entirely through your mouth. Some swimmers find they cause headaches after prolonged use. If you can tolerate them, though, they are probably the single most effective nosebleed prevention tool for pool swimmers. Look for soft-padded clips rather than rigid ones, and try a few brands until you find one that sits comfortably on the bridge of your nose without sliding off during turns.
Pre-Swim Nasal Preparation
If a nose clip isn’t an option, or if you want to layer on extra protection, coating the inside of your nostrils before swimming helps shield the tissue from chlorine and drying. A thin layer of petroleum jelly (Vaseline) applied with a clean fingertip or cotton swab just inside each nostril creates a barrier that repels water and keeps the mucosa moist. Some swimmers prefer water-based saline gels, which are less greasy and specifically designed for nasal use. Either works. The goal is to prevent chlorinated water from making direct contact with your nasal lining.
Timing matters. Apply the barrier right before you get in the pool, not 30 minutes ahead, because blowing your nose or wiping your face can remove it. Re-apply if you take a long break between sets. You don’t need a thick glob; a thin, even coat is enough. Too much petroleum jelly can drip down the back of your throat and feel unpleasant.
Staying hydrated also helps in a less obvious way. Dehydration thickens the mucus in your nose and makes the tissue drier, which weakens its defense against irritation. Drink water before and during your swim, especially in warm, humid indoor pool environments where you may not notice how much you’re sweating.
Post-Swim Care
What you do after the swim matters as much as what you do before. Chlorine residue can linger in your nasal passages long after you’ve left the pool, continuing to dry and irritate the tissue. A gentle saline rinse after swimming flushes out that residue and rehydrates the mucosa. You can use a squeeze bottle, a neti pot, or a simple saline spray from any pharmacy. Tilt your head forward, squirt the solution in one nostril, and let it drain out the other.
Research into chronic nosebleed management has found that regular saline nasal sprays can reduce nosebleed severity on their own. In one randomized trial, participants who used a saline spray twice a day saw improvement comparable to those using medicated sprays, with severity scores dropping meaningfully over a 12-week period. The saline group did just as well as the drug groups, suggesting that keeping the nasal tissue moist is the core factor in preventing recurrent bleeds.
After rinsing, applying a small amount of petroleum jelly or a saline-based nasal gel locks in moisture and protects the healing tissue. Avoid picking at your nose or blowing it aggressively after swimming. If you feel congested, a gentle blow with one nostril at a time is safer than a forceful two-nostril honk, which can spike the pressure inside your nasal cavity and burst a weakened vessel.
Swimmers With Allergies or Chronic Nasal Issues
If you already have allergic rhinitis, hay fever, or chronic sinusitis, swimming is likely to make your nasal symptoms worse. Chlorine exposure can aggravate pre-existing allergic inflammation and, separately, trigger a non-specific irritant response even in people without allergies.5British Journal of Sports Medicine. Allergic and Non-Allergic Rhinitis in Swimmers: Clinical and Cytological Aspects In one study, roughly 44 percent of symptomatic swimmers had allergic rhinitis and 35 percent had a neutrophil-dominant inflammatory pattern consistent with chemical irritation rather than allergy. Both groups had swollen, irritated nasal tissue that bleeds more easily.
If you fall into either camp, talk to your doctor about using an antihistamine nasal spray or a corticosteroid spray before swimming. These reduce the inflammatory response that weakens the lining and can give your nose a better chance of surviving the chemical exposure. In the same study, nose clips helped swimmers with the irritant-type inflammation more than those with the allergic type, so clips and medication together may be the most effective combo for allergy sufferers.
People who take blood-thinning medications, including daily aspirin, should be aware that their nosebleeds may be harder to stop once they start. The prevention steps are the same, but you’ll want to be more diligent about all of them, because a bleed that would clot in a few minutes for someone else might take significantly longer for you.
Open Water, Salt Water, and Other Environments
Pool swimming is the biggest nosebleed culprit because of the chlorine, but open water swimming has its own risks. Ocean water is salty and mildly antiseptic, which some swimmers find less irritating than chlorine. However, salt water can still dry out the nasal lining, especially during long swims. Cold ocean or lake water intensifies the temperature-driven swelling and shrinkage cycle described earlier.4PubMed. Nasal Reaction to Changes in Whole Body Temperature
Freshwater lakes and rivers are gentler on the nose chemically, but they come with their own concern: bacteria and parasites. Forcefully pushing freshwater up your nose in unchlorinated bodies of water carries a small but serious infection risk. This isn’t directly related to nosebleeds, but it’s worth mentioning because some swimmers try nasal rinsing with lake water after a swim, which is a bad idea. Always use sterile or distilled water for any nasal rinsing, never tap water or water from the body you just swam in.
Saltwater pools, which use a chlorine generator to produce chlorine from dissolved salt, are often marketed as gentler alternatives. They do tend to have lower chloramine levels and feel less harsh on the eyes and skin. The chlorine concentration is generally lower and more stable than in traditionally dosed pools. If chemical irritation is the main trigger for your nosebleeds, a saltwater pool may help, though it won’t eliminate chlorine exposure entirely.
Dive-Related Pressure and Nosebleeds
If your nosebleeds happen specifically during dives, flip turns, or underwater swimming, pressure changes may be a factor on top of the chemical and temperature issues. When you dive below the surface, the water pressure increases on your sinuses and nasal passages. The blood vessels in Little’s area are already fragile; the added pressure can push them past their breaking point.1PubMed Central. Kiesselbach Plexus This is similar to what scuba divers experience with sinus squeezes, though at much lower intensity in a pool.
Equalizing pressure by gently exhaling through your nose as you descend helps prevent this, but it also forces pool water into your nasal passages, which brings you back to the chlorine problem. Nose clips solve this for most pool swimmers by preventing water entry, though they aren’t practical for scuba diving. If you’re a competitive swimmer who does a lot of flip turns, you might notice that nosebleeds happen more during hard training sessions, simply because you’re doing more turns and forcing more water up your nose at speed.
When Nosebleeds During Swimming Deserve Medical Attention
Occasional nosebleeds during or after swimming are common and usually nothing more than irritated tissue. But some patterns warrant a visit to your doctor or an ear, nose, and throat specialist. Bleeds that last longer than 20 minutes despite steady pressure on the soft part of your nose, bleeds that flow from both nostrils simultaneously, or bleeds that recur multiple times per week are all worth investigating. These can indicate a vessel that needs to be cauterized, a clotting issue, or an anatomical quirk like a deviated septum that exposes more tissue to irritation.
Cauterization sounds intimidating, but it’s a quick office procedure where the doctor seals a specific vessel with silver nitrate or an electric current. For swimmers with one particular spot that keeps reopening, it can be a lasting fix. After cauterization, you’ll typically need to stay out of the pool for a week or so to let the site heal before chlorine exposure starts again. Your doctor may also suggest using a humidifier at night during the healing period, since dry bedroom air can crack the fresh scar tissue.
Children who swim competitively and get frequent nosebleeds often outgrow the problem as their nasal tissue matures and thickens in the teenage years. In the meantime, keeping a nose clip in the swim bag and applying petroleum jelly before practice covers most cases. If a child’s nosebleeds happen outside of swimming too, especially during sleep or in dry winter air, the issue is more about the nasal lining generally than about the pool specifically, and a pediatrician can help sort out whether a daily saline routine or a brief course of nasal moisturizer is warranted.