Tag Archives: salt mouth

Limiting Factors in Marathon Swimming – Part 1 – Physical Factors

The northern hemisphere summer swimming season is on the horizon , though it doesn’t feel like it here in Ireland where we’ve been having the coldest spring “since records began” (that phrase we are all familiar with from the past few years).  there will be big swims, both attempted and successful. 

Before genuine and extravagant claims are made by ill-informed media covering swims about which they know little and understand less, I though it might be worthwhile to round up the limiting factors for ultra-endurance marathon swims that might help people to apply some criteria to help evaluate some of those swims. Limiting factors which constrain or control a process.

Limiting factors on marathons swims can broadly be said to fall into three categories, with further subdivisions in two of those three.

  • Physical
  • Environmental
  • Psychological

In this first part we will consider the physical limitations.

The Physical Constraints to long swims pertain to the individual swimmer and will be influenced by their experience, training, and preparation.

The god bottle
The god bottle

Energy: Often seen by non-swimmers as the defining criteria, Energy relates to the swimmer’s ability to keep swimming. For experienced marathon swimmers however this is not often the as critical as is seen from outside. Evan and I have covered marathon feeding aspects in the past, from mechanics to content and possible supplementation, but the simple fact is that a tested feed plan, appropriate for the conditions and swimmer, will usually provide the pre-requisite energy. Most marathon swimmers use concentrated carbohydrate as the primary feed, with electrolytes to keep the body’s systems operating.  Changes to this basic plan vary with the swimmer but as long as the swimmer can keep feeding, they will take in sufficient energy.

Digestion: There is often talk of vomiting amongst marathon swimmers. Many, and I am one, think it is worthwhile to get used to being able to swim if or even while vomiting. While many swimmers put the pre-disposition of marathon swimmers to vomit at the door of feed plans and high carbohydrate loads, I think there can be other possible causes, (though the body regardless of size can only process so much carbohydrate per hour). Additionally  there are also the small amounts of salt water that even very experienced swimmers can take in due either to the odd mouthful of choppy water, or salt spray in rough conditions. And which I think is important but unquantified, is the extended time in a prone position which could hinder digestion. Peristalsis, the contraction of internal muscles to move food through the digestive process, has been shown in studies to be independent of gravity for most positions (unsurprisingly, since the intestine leads in all directions). Though peristalsis in the prone head-down position was not shown to be statistically abnormal (i.e. the swimming position) those studies were of short duration.  It is possible, but undetermined, if a longer time period could cause a greater likelihood of digestive problems causing vomiting. Vomiting during a swim usually isn’t particularly energy-consuming , and can even be a relief for once-off incidences. But should the vomiting frequency increase  greater distress can be caused and lead to a collapse in energy.

Nothing_Great_Is_EasyStrength: Like energy, strength is often more considered a limiting factor by non-swimmers. Marathon swimmers don’t often operate on strength alone but more usually on continuous repetition obviously and on technique. Hundreds or thousands of kilometres of swim training act as low-repetition strength training and cause swimmers to have very strong (if not very defined) muscles. A typical training load of a thousand kilometres a year (some swim less, some swim much more) prepares distance swimmers physically. Marathon swimmer’s embrace of the Nothing Great is Easy aphorism is simply one of our ways of explaining that physical strength is not the most important attribute.

Typical English Channel swimmer with salt mouth
Typical English Channel swimmer with salt mouth

Salt Mouth: I’ve written on Salt Mouth specifically as being a serious limiting factor for long swims. In brief it is the build-up of salt in the swimmer’s mouth and throat which can in the worst cases lead the swimmer to be unable to feed or even swallow, and can cause the sloughing of the epidermis of the tongue and throat. It can be extremely painful. Only swimmers who have run into this can understand how painful it can be. With all the talk of stinger suits and shark protection, I think ways this problem is far more important for those willing to risk  extending the outer limits of distance swimming. When evaluating a long swim it is worth looking at the salinity of the region. Kevin Murphy’s record 53 hours in the English Channel was in a region of higher salinity and is one of the many reasons swimmers who understand this limiting factor hold Kevin in such high esteem. Swims in the Caribbean such as Chloe McCardels or Penny Palfrey’s Cuba to Florida swim attempts are also in a region of high salinity. The US West Coast is lower salinity that the US East Coast and the Mediterranean is higher than any of these.

Global ocean salinity
Global ocean salinity

Sleep: If you’ve ever missed a night sleep and spent the next day in an utter daze, one may find it hard to imagine that sleep deprivation in itself is not as much a limiting factor as one may guess. There are studies showing that the sleep two nights before a big athletic event is of more importance that of the preceding night. And the majority of English Channel swimmers start their swim in the middle of the might and will miss most if not all of sleep of the night before. Once actually swimming, and assuming the swimmer has the requisite physical and mental stamina, lack of sleep for a second night does not seem to be the most critical factor. Obviously scientific study of the whole of marathon swimming in low enough given the small numbers involved, but the numbers of people who have swum over 24 hours (the 24 hour club) is very small with no scientific study to speak of, and only inferences can be made. Key is probably the factor that the athletic endeavour of marathon swimming is well below the swimmer/athlete’s VO2 Max ability, (what the athlete is capable of at their threshold limit).

Stroke training
Stroke training

Technique: Marathon swimmers range in style and technical ability. Some are not at really graceful or obviously and some like Evan or Trent are elegant controlled swimmers. Most of us though fall in the the wider intermediate range. We train technique along with all the other aspects and just are there are different ways to skin a cat there are different techniques in swimming from a bludgeoning powerhouse to a smooth FLOWer. Excellent technique in itself is not a determiner of success in marathon swimming, but equally being a powerhouse swimmer isn’t either. Good technique though is much less likely to lead to an overuse injury during a significantly long swim. Slight stroke imbalances when repeated 30,000 times for an average English channel swim, or even more for more epic swims, accumulate tiny stresses in the body of the swimmer, especially the neck and shoulders, that could lead to injury during a swim.

Coming in Part Two, environmental limiting factors of marathon swimming.

Physiological effects of long and marathon swims – Salt Mouth

Salt Mouth

Unlike Third Spacing of Fluids, salt mouth is one of the most common and least visible or appreciated effects of marathon swimming and can cause the swimmer great distress and discomfort, and yet it’s invisible to everyone else.

Typical English Channel swimmer the day after
Typical English Channel swimmer’s throat

Salt Mouth is the effect of salt build up on the tongue and in the mouth and throat. The extent of the effect is directly proportional to the immersion time obviously, but less obviously to the salinity.

We sometimes speak about the limiting factors of distance swimming being hypothermia or jellyfish or currents, but salt mouth is also one of the most significant limiting factors for very long swims. At its worst salt mouth can inflame the throat, make swallowing nigh on impossible and the swim ends. Some swimmers even report shedding the entire surface of the tongue and throat.

For myself post-swim initial mild discomfort starts after about four or five in salt water. For a swim less than ten hours the discomfort doesn’t last more than 24 hours (e.g. Manhattan) and often only overnight.

However for longer swims the discomfort or even pain can be quite significant. After my English Channel, I had a lot of discomfort for over three days, to the extent that eating was painful. Lisa Cummins was in a lot more pain after her 35 hour two-way crossing, that took even longer to abate.

Alan Clack during a feed
Alan Clack during a feed

For those unused to swimming in the sea, a marathon sea-swim can be a painful experience with the salt mouth gradually building up from early on during the swim. Other swimmers may just notice a gradual loss of taste during feeds and not detect the extent of the build-up until after the swim.

I’ve said above that salt mouth is less obviously related to local salinity. This is because people often don’t realise the different saline levels around the world and often come from a lower salinity region. The south coast of Ireland is about 4% whereas the English Channel is about 4.5 to 5%. That’s a 15-20% increase. Over 5% isn’t even considered salt water but brine, (though we use the terms interchangeably). The west coast of the US for example is around 3 to 3.5%. Ocean temperature obviously affects salinity but so does ocean size and mixing. The Mediterranean Sea has higher temperatures and a smaller area so the saline solution becomes more concentrated.  In the English Channel the water is constantly pushed and pulled up and down the Channel by tides and can’t escape so the salinity increases.

Global ocean salinity
Global ocean salinity

The most usual method of combating salt mouth is for the swimmer to take a dilute mouthwash solution regularly during the swim. Undiluted mouthwash during a swim can the swimmer’s mouth to feel burned. Dilution rate is a personal choice, but usually 25%, 33% or 50%. I use 33% as I find 50% is still too strong. Frequency is also personal; Alan Clack asked for an increase of mouth wash during his Channel Solo, as he could feel his throat getting sore and he was getting a mouthwash about every 90 minutes and it seemed to work for him. Of course this needs to be always balanced against the time taken for the mouthwash.

The other key method of combating salt-mouth is to change your breathing pattern such that you are exhaling through your nose in salt water. Most experienced swimmers will exhale through both nose and mouth, especially in the pool.  This is partially related to the effort expended. But for a marathon swim the swimmer is maintaining a lower rate of exertion and it is possible with practice to exhale through the nose only, reducing the exposure of the mouth to salt water.

A method that hasn’t really been explored yet but which was mooted by a dentist friend is to line the inside of the throat with a protective barrier. Should this happen, it will doubtless be a future area of rules contention.

Karen Throsby says the black jelly babies are best

Kendal mint cakeApart from these two methods swimmers choose various food items which seem effective at temporarily combating or relieving salt mouth. Tinned peaches and jelly babies are amongst the most popular. Ice-cream after swims is also popular for this reason. I found Kendal Mint Cake useful during training swims. For those unaware of Kendal Mint Cake, it isn’t a cake but compressed glucose with a slight hint of mint, famously used in early 20th Century mountain-climbing and polar expeditions and still very popular with climbers for its compact size and high energy content. Later in swims though as the mouth cools it is difficult to melt and swallow.

Overall Salt Mouth should not be dismissed as a mere inconvenience but as another of the potentially serious limiting aspects of swims, which require consideration during training and investigation of preferred methods of alleviation.

EDIT: Have a look at English Channel Soloist and Utah resident Gordon Gridley‘s extreme salt tongue photo in the comments below. Gordo trained and did his English Channel qualifier in the Great Salt Lake, where salinity is far greater than the open ocean.