Why 31 C in Open Water Swimming? Part 2 — The Dangers of Hot Water Swimming

By Steven Munatones, Swimming World Open Water Contributor

Editor's Note: This is the second in a three-part series on FINA's rules that allow open water swims to be conducted in water over 31 degrees Celsius (87.8 degrees Fahrenheit).

Click here to read Part One.

HUNTINGTON BEACH, California, October 28. WHILE FINA professional marathon races are usually limited to 80 or fewer athletes, a large majority of amateur swims are flooded with much greater numbers of participants. While FINA-sanctioned races have sufficient boats and safety personnel for each swimmer throughout the course in the post-2010 era, this is not the case with almost every other amateur swim (bar swims where each swimmer is escorted by their own crew).

In a review of the 29 deaths that have occurred since 2010, a majority of victims who ultimately died in the race were first seen or assisted by a fellow swimmer. In other words, the first responder is usually another swimmer. So the question arises, are all swimmers in a given race even aware of this situation? Do they know that there is a greater possibility of them saving a fellow swimmer — at least initially — than the race officials? Are they aware of danger signs in the water, what the risks are, or what to do in an emergency?

USA Swimming and FINA educate its membership in a variety of ways through camps, clinics and coaching education programs. USA Swimming has also established a maximum water temperature for open water competitions and mandated more stringent safety procedures including greater number of safety vessels and independent monitors. Sometimes, this leads to races being cancelled or modified. Sometimes, races do not even get sanctioned. As a result, the governing bodies have elevated the level of safety awareness and broadened its safety net.

And none too late.

FINA similarly revised its own policies and rules. Some of the rules were influenced by the recommendations of the Pound Commission that concluded its report in 2011; some were a result of FINA's own investigations and conclusions. Ten days before the 2012 London Olympics, the FINA Bureau — the ultimate rule-making body in the global institution — passed its own separate set of rules.

USA Swimming New Rules

USA Swimming passed new rules in September 2011 that specifically addressed maximum water temperatures and added consideration for warm air temperatures:
702.2 WATER/AIR TEMPERATURE — The race shall not begin if the following conditions are not satisfied:

.1 The water temperature shall not be less than 16 degrees C (60.8 degrees F).
.2 For races of 5K and above, the water temperature shall not exceed 29.45 degrees C (85 degrees F).
.3 The air temperature and water temperature when added together shall not be less than 30 degrees C (118 degrees F) nor greater than 63 degrees C (177.4 degrees F)

FINA's New Rules

FINA's new open water safety regulations approved in July included the following:

4.7 Water Temperature
(a) The water temperature shall be measured 2 hours before the start of the race and must be a minimum of 16 degrees C and a maximum of 31 degrees C. The water temperature shall be certified by the FINA Safety Delegate and the HMF/OC Safety Officer as measured in the middle of the course, at a depth of 40 centimeters.

(b) The water temperature shall be monitored as provided above at one-hour intervals during the race. If the water temperature drops below 16 degrees C or exceeds 31 degrees C at any one of the measuring intervals, the water temperature shall be measured again in 30 minutes and if that measurement is also below 16 degrees C or exceeds 31 degrees C the race must be stopped.

i The minimum and the maximum temperatures are under a study by the specialized University of Otago (NZL) as requested by FINA, IOC and ITU [International Triathlon Union]; when the results of this study are available, this Regulation will be amended accordingly.


To put these temperatures in perspective, imagine a swimming pool at 85 degrees F (29.4 degrees C). Even at 82 degrees F or 83 degrees F, performances start to suffer in a pool. At those temperatures, coaches constantly hear complaints that “the water is too hot” from their swimmers. Coaches use aerators and move workouts to the early morning or evening to avoid pool temperatures that are too warm.

Now imagine doing 100 x 100 on an interval where you get very little rest in a pool where the water is 85 degrees F…on a humid, cloudless day. How tough would that be? Any coach can easily imagine problems with heat stress among his athletes under those conditions.

Now imagine if the temperature of the pool was 87.8 degrees F (31 degrees C)…for a race.

Now add to this increasingly hazardous situation the well-known fact among open water swimmers that the temperature of fresh water always feels cooler than the same temperature of salt water. That is, 80 degrees F in fresh water does not feel like 80 degrees F in salt water. The fresh water feels cooler. Flipped around, the salt water feels WARMER. That is, 80 degrees F in fresh water feels more like 82-83 degrees F in salt water depending on the amount of solar radiation. This is not the opinion solely of this writer, but a well-accepted understanding from experienced open water swimmers.

So essentially that 87.8 degrees F in a fresh water pool feels more like 89-90 degrees F in the ocean, sea or estuary.

Now imagine racing 5,000 meters or 10,000 meters or 25,000 meters in 89-90 degrees F. Pool swimming coaches would not stand for it; parents would complain; and athletes would — out of pure physiologically necessity — purposefully slow down and complain until the coach relented.

This is what is happening in the open water world.

FINA institutionalized rules that include a maximum water temperature of 31 degrees C (87.8 degrees F). But there is a caveat, a very important caveat. In the case of USA Swimming, the maximum water temperature is 29.45 degrees C (85 degrees F). No questions asked. Race stopped. Game over. Swimmers go home.

Under FINA rules, the water temperature is monitored at one-hour intervals during the race. If the water temperature drops below 16 degrees C or exceeds 31 degrees C during one of these one-hour intervals, the race is not stopped. The race continues. The swimmers are still asked to race.

The race officials are instructed by FINA to wait another 30 minutes and then take a second measurement. If that second measurement is below 31 degrees C, the race continues. If the measurement exceeds 31 degrees C then the race is stopped.


Experienced swimmers know that when the water temperatures rise up to 31 degrees C, then the air temperature tends to be even higher than 31 degrees C. And it is occasionally accompanied by high humidity.

As a result, swimmers and coaches around the world do not believe that the new FINA rule is enhancing the safety of open water athletes. Not for a second.

Athletes know it. Athletes instinctively understand the tremendous physiological stress placed on their bodies under this scenario. It is like swimming through a furnace. Every breath fills the lungs with warm water, the body cannot perspire and cannot physiologically adapt to the cumulative heat forces on their bodies.

Less than two years after the death of Fran Crippen, why is FINA deciding on a figure that is obviously not helping improve safety?

The Right Answers

To be fair, neither FINA nor the open water swimming community has conducted sufficient research to arrive at the optimal maximum temperature levels. No one knows if 29 degrees C or 30 degrees C or 31 degrees C or 32 degrees C is the right number. There simply is not enough data to properly pinpoint and scientifically institutionalize as the optimal number.

And that is scary.

Under this current scenario where neither FINA nor the global open water swimming community knows the right number, why does FINA chose a number that is obviously high? Is it not better to be conservative and play it safe — or safer? Why risk — even with remote possibilities — another tragedy?

Every competitive swimmer in the world will explain to any administrator that 31 degrees C is too high. If the athletes believe and know this, why isn't FINA listening? Its decision and unwillingness to listen to the athletes who are putting themselves at risk is puzzling beyond comprehension.

This decision to select 31 degrees C is especially puzzling because few races on the current FINA World Cup and Grand Prix circuits have the possibility to get up at water temperatures this high. Whether a swim is in Brazil, Argentina, Canada, Macedonia, or Serbia, the water temperature is traditionally not at this level. The water in Mexico and China has a greater possibility to be warmer, but usually, the water has been significantly cooler than 31 degrees C.

So why choose 31 degrees C?

Given this information and historical fact, there is no justification to institutionalize a rule that allows world-class athletes to race 5 km, 10 km and 25 km in water temperatures up to (and above) 31 degrees C. Just because there might not be a problem is not sufficient justification to select this high number.

Be conservative until there is more data. Play it safe. There is no realistic possibility of cancelling any races on the current FINA Grand Prix or World Cup series, so there should be no problems.

FINA Global Influence

The problem globally becomes even greater because when FINA decides water temperatures can rise to those levels, there are races around the world that will also allow their races to be conducted in water temperatures at those similar temperatures. For less well-trained athletes and overweight adult swimmers who make up the majority of open water swimmers in the world, it is especially a deadly combination when water temperatures increase to 31 degrees C and air temperature are even greater.

Unfortunately, Fran Crippen and others are tragically no longer here to argue this point.

In addition to world-class professional marathon swimmers, almost every experienced amateur swimmer will admit that racing in 31 degrees C is unhealthy and unsafe. At best, it is highly uncomfortable and presents an avoidable element of risk to an already risky aquatic discipline. This is not a matter of debate; it is a fact. But swimming casually in a practice with friends is one thing; racing for money in a competitive situation is something much different.

FINA Research

Apparently researchers at the University of Otago in New Zealand provided FINA with scientific justification that suggests racing competitively in 31 degrees C water temperature is not unsafe. This could be the only logical conclusion to FINA's written statement, “The minimum and the maximum temperatures are under a study by the specialized University of Otago (NZL) as requested by FINA, IOC and ITU; when the results of this study are available, this Regulation will be amended accordingly.”

Potential Problems

Here are at least four potential problems with these new regulations:

1. Increase in air and water temperature during competitions
Because many FINA races start in the mid-morning or early afternoon, the air and water temperatures tend to rise during a competition. According to these regulations, what happens in a 10 km or 25 km race where athletes are swimming for over an hour and the water temperature reaches 32 degrees C? The FINA officials will then measure the water temperature at a depth of 40 cm 30 minutes later and, perhaps, find the water temperature has increased. So the athletes would swim over 1 hour 30 minutes under these unbearable, unsafe conditions.

2. FINA's belief that 31 degrees C is bearable for trained athletes
Every open water swimmer knows to expect the unexpected. At temperatures above 28 degrees C even for lean athletes from tropical countries, the water temperature is too high. For athletes from cooler climates, these temperatures are unbearable and can only lead to problems with hyperthermia. There are many concrete examples from global open water swimming competitions that prove this point.

3. FINA's lack of consideration of air temperature and solar radiation
FINA does not take into account the ambient air temperatures (usually higher than the water temperatures) or other climatic conditions (e.g., cloudless, windless day) in its regulations.

4. The cumulative effects of heat stress are dangerous
The cumulative effects of the warm water and the solar radiation on the backs of the swimmers added to the limited hydration that swimmers take relative to land-based endurance athletes and the stress of racing in a dynamic environment, after a restless night of sleep, is a lethal cocktail. No matter what the research is conducted in controlled conditions in a university laboratory, the research cannot possibly accurately predict what happens to an athlete on race day under such conditions.

FINA Competitions

In discussions with FINA's Medical Delegate at the 2011 FINA World Swimming Championships in Shanghai, the doctor explained that the medical threat to the swimmers in the 25 km was not significant despite temperatures that exceeded 31 degrees C in the water and well above that for the air temperature during a hot, humid day. “There is more a risk of heat stress in the 10 km when the athletes are swimming faster than in the 25 km.”

Based on his decision, the 25 km race at the 2011 World Championships continued to its conclusion. Several athletes dropped out and one had to be saved, but the FINA pointed out that because the best athletes completed the race, there was no reason to stop the race.

During the last four FINA World Swimming Championships, there have been serious threats to athletes' safety.

In 2005 at the FINA World Swimming Championships in Montreal, an American athlete started to have problems before halfway and then significantly slowed down with a kick during the second half of the 25 km race. A coach had been watching the struggling athlete as a precaution as he walked alongside the Olympic rowing basin course near the athlete. When it became clear the athlete was in distress and could not go further, he ran into the water to help the athlete to shore. An ambulance was called and the American doctor went with the athlete to the hospital.

In 2007 at the FINA World Swimming Championships in Melbourne, a sudden squall hit the 25 km race. Sheets of rain, severe winds and tremendous surface chop created serious issues not only for the athletes who were spread all over the 5 km loop course, but also for the coaches and officials who were on 2 floating barges along the course. Tents, flags and the finish structure onshore were torn apart and flew horizontally with the winds. Turn buoys were ripped from their anchors and it was an emergency that required quick decision-making. Among the first people off the course were the timing officials. “Forget the equipment, we have to get off this [finish structure],” were among the statements made. If it were not for the quick decision-making of the FINA officials and fast-acting Australian lifeguards who zipped around the course saving coaches, officials and swimmers in their inflatable rafts, it would have been a disaster making the news. That day, the FINA Technical Open Water Swimming Committee officials and Australian lifeguards proved why their competence and concern. The officials made the right call and acted in the best interests of everyone involved, while the lifeguards repeatedly went through the squall to make saves. The race was rightly and immediately halted.

But FINA executives back at the pool complex were upset that there were not first consulted regarding the unplanned stoppage of the race. Why was the professionalism of the FINA Technical Open Water Swimming Committee experts during the potential disaster at the site questioned – at all – by FINA executives who were in an indoor stadium far away?

In 2009 at the FINA World Swimming Championships in Rome, a FINA referee noticed an Australian swimmer struggling during the 25 km race. He asked that his boat be moved closer to the athlete. He observed the athlete for some time and became worried. Then, without warning, she started to go under. Acting quickly, he literally saved her by grabbing her hair as her limp body was raised to the surface and brought onboard.

Another disaster averted. Despite no official record of his heroic action by FINA, the official knew he had done the right thing. “Our first priority out there is the safety of the athletes, especially since it was so rough out there.”

In 2011 at the FINA World Swimming Championships in Shanghai, a German athlete was involuntarily pulled to safety during the 25 km race while several other athletes either did not start because of the unsafe conditions or voluntarily pulled out – including the 2009 men's world 25 km champion, the 2010 men's world 25 km champion, and the 2010 women's world 25 km champion.

Is this what the athletes deserve? If your son or daughter were competing, would you be satisfied with the current situation and new rules? Is this the leadership that athletes and coaches should expect from the world's governing body in aquatics?

We think not.

FINA is a global institution with a remarkable level of success. It does so many things right. The institution has helped spread the passion of swimming around the world. FINA will only continue to help the aquatic sports prosper, but it will also help swimming play a larger role in local communities and within the Olympic movement. But this maximum water temperature is its Achilles heel.

Amending this 31 degrees C rule should be a relatively simple issue.

Steven Munatones is a former national marathon swimming champion and coach, and can often be found on a pontoon or chase boat in many of the biggest open water swims. He is the editor and founder of The Daily News of Open Water Swimming.

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