Marathon Swimmer Health

Acute urinary retention in long distance swimmers

By Steven Minaglia, MD

Nothing can be more unsettling during a long swim than having a strong urge to urinate and not being able to do so.  As this goes on the sensation can intensify to the point of great discomfort and an inability to keep swimming.  I have personally seen this happen to a friend of mine during a winter session of the Maui Nui Swim.  We were just over halfway between Maui and Molokaʻi on day 3 when John could not continue.  We talked about it.  I provided some tips.  He tried many times and ultimately had to get vertical on the boat for a brief moment before he was finally able to empty his bladder.  He knew this would result in disqualification yet minutes later he returned to the water and was able to complete the 3rd channel crossing of the 3-day event.  He was in his 30s at the time and generally low risk for having urologic conditions.

So what happended when he stood?  How was he able to urinate so easily just with a position change?  Think about how we generally empty our bladders.  We are usually sitting or standing with the occasional squat.  There is a vertical posture, some reliance on gravity and some reliance on internal organs increasing bladder pressure making it easier to empty.  Think about emptying your bladder (voiding) as an equation where the net contributors to emptying need to overwhelm the net contributors to storing urine.  In John’s case he could not empty his bladder in any position while in the water that day.  By briefly standing on the boat, he returned to a familiar position in which he was able to leverage gravity, increased bladder pressure, and some important mechanics in order to empty.

What are the mechanics?  How do we empty our bladders?  It is a simple answer with complex physiology behind it.  We must first voluntarily relax our pelvic floor.  This signals the bladder detrusor muscle to involuntarily contract and empty the bladder.  For everything to work correctly the bladder needs to contract and the bladder neck needs to relax.  Anything that prevents this coordination will promote storing the urine.  Abnormally high pelvic floor tone or an enlarged prostate gland, for example, can make it difficult for swimmers to urinate.  Additional conditions related to a long distance swimming event can tip the person toward retention in the equation referred to above.  Adrenaline (epinephrine), for example, causes the bladder to relax and thereby favors urine storage.  Perhaps John just had an adrenaline high?

As a long distance swimmer it took me a long time to learn how to urinate while swimming.  I found that dropping my kick and relaxing my pelvic floor was the key to initiate the stream and anytime I resumed kicking it became difficult to continue urinating.  Thus patience, focus, and form are important to getting the job done.  If the event is long and seconds don’t count then its okay to pause, relax, and let it go.  Urinating during very long swims is basically a vital sign of the swimmer.  If you are swimming hours and hours without voiding you are most likely dehydrated and need to adjust your fluid intake.  If you add vomiting and sea sickness you are in dire straits and probably should not continue.  If you have associated strong urgency to void you are likely in retention.

Here is a simple way to measure one baseline urologic function.  It is not comprehensive and if you are concerned you might have a urologic problem then consult a healthcare professional.  Place a measuring device into your toilet or urinal.  A hospital grade urine receptacle with the measurements marked works best.  In theory you can use anything that will allow you to catch all of the urine and accurately measure how much comes out.  You want to urinate in a position you are familiar with.  Squatting over a bucket when you don’t normally do so is a bad idea.  While you void use a stopwatch to record the entire time you hear urine flowing.  You then divide the volume voided by the number of seconds it took to void.  A normal average flow rate is at least 15 milliliters (mL) per second for both men and women.  A normal voided volume for both men and women is approximately 200-500 mL and this can vary greatly based on many factors including hydration, level of activity, temperature, and health conditions to name a few.  Being able to measure the amount of urine that remains in your bladder after voiding is more comprehensive and requires additional equipment.  More sophisticated testing methods are available through your healthcare provider.

Unfortunately, there are no studies that analyze urinary retention in long distance swimmers.  It is likely that acute urinary retention can still occur in a swimmer who otherwise has normal baseline urologic function.  It is therefore prudent to consider the following tips if this has ever happened to you while swimming.

First, it is important to look at all the medications and supplements you are taking.  Many commonly prescribed medications can favor urinary retention.  Do a deep dive on the side effects.  Sudafed, a commonly used over the counter decongestant can push an already vulnerable individual into acute urinary retention.  If it is a supplement then discontinue it.  If it is an important medication then consult the prescribing healthcare provider to determine if it is safe and appropriate to either discontinue the medication or pause its use around the time of your swim event.

Practice voiding during swim practice.  I’m not endorsing peeing in the pool.  Hopefully you are also practicing in a lake, river, or ocean.  Many swimmers can master the art of voiding even while they continue swimming.  If not, try to void at least a few times during the time you are in the water.  Being able to do this suggests normal urologic function and will also build confidence.

Stay ahead of the problem.  Try to void shortly after your first urge to urinate.  If you cannot then try again soon.  The more urine you store in the bladder the more difficult it can be to generate a strong enough bladder contraction to empty.  Don’t hold it.  Urine production can vary widely due to multiple factors including intake, temperature, and effort.  Have you ever overfed during a long swim just because you were afraid of underdoing it?  Cold water can also contribute to excess urine production when the blood shifts toward the central circulation to preserve heat.  In contrast if the water is hot and/or you are generating a lot of heat through effort then you would make less urine.  Basically, you want to be aware of factors that can either fill your bladder fast or not at all.

Lastly, relax.  Urinary urgency can provoke anxiety.  Perhaps your adrenaline is too high.  Before quitting try to pause long enough for your heart rate to approach baseline.  Too little is known about this condition in long distance swimmers and it is possible that applying strategies based on basic physiologic principles will prevail.  Time will tell as more and more take to the water and more data is generated.  For now, consider a visit to your healthcare provider to assess your risk and/or to diagnose and treat any urologic conditions.  Focus on event specific factors that may further contribute to the problem.  Address all physiologic functions during your training and preparation.  After all, luck favors the prepared.