Table 1.

Nutrition-related adverse outcomes in endurance and ultra-endurance competitions and sports, in cohort studies.

Study	Objectives	Sample	Sporting Competition	Adverse Outcomes	Incidence	Causes	Conclusions
Parkkali et al. (2017) [24]	-To determine the origin and prevalence of GI problems in participants in triathlon y duathlon -To adopt preventative measures for future events.	239 athletes -80 F -159 M	Triathlon and duathlon, The Netherlands (2015)	Acute GI illnesses	GI illnesses: 73 cases (30.5%) -Stomach pain: 52 cases (71%) -Nausea: 56 cases (77%) -Diarrhea: 43 cases (59%) -Vomiting: 28 cases (38%)	Consumption of energy drinks and ingestion of sips of water from the canal in which the swimming event took place.	-The rate of appearance of the symptoms in the 2 days after the event suggested a viral origin, which was confirmed by the detection of norovirus in feces samples. -The open-water swimming events were the most probable source of the infection. -No food or drink, except the energy drinks, was associated with the GI illnesses.
Meyer et al. (2017) [25]	-To evaluate the incidence of diarrhea in a hiking trail. -To determine the seriousness and causes of this GI problem.	737 athletes -281 F -420 M -36 unspecified	John Muir Trail (JMT), long-distance hiking trail, USA (2014)	GI problems: diarrhea.	Diarrhea: 121 cases (16.4%) -Mild: 99 cases (82%) -Moderate: 16 cases (13%) -Severe: 6 cases (5%)	Fecal contamination of the natural sources of water ingested, together with poor handwashing on the trail.	-The incidence of diarrhea is relatively low compared with other long-distance trails in the USA. -By following standard hygiene recommendations and using filtration or treatment methods for the water, the prevalence of GI problems in this type of event could be reduced.
Magee et al. (2017) [26]	To evaluate the hydration and physical state of university athletes according to the sports and disciplines practiced.	429 athletes Runners: -54 M Cyclists: -7 F -22 M	-Runners: 5 cycles of 2 km on uneven terrain. -Cyclists: cycles of 100 km with a rise in altitude of 1000 m. Ireland (2016)	DH	Total DH: 187 cases (43.6%) -Runners, post-training: 6 cases (12%) -Cyclists, post-training: 13 cases (45%)	Lack of knowledge about the liquid requirements and nutritional values of the athletes.	-Many athletes consume insufficient liquid during physical exercise. -The opportunities to drink water and other liquids during the events are too limited. -There are more drinks-breaks during team sports; even so, the participants do not consume enough water to avoid DH.
Brustia et al. (2016) [27]	-To obtain information about the risks involved in mountain sports, so that adequate information can be supplied. -To develop recommendations for health and safety teams.	202 athletes	Endurance sports in the French Alps, at 2500 m altitude. (2013)	Injuries due to cold and HT.	Injuries due to cold: 13 cases (6.4%) Due to HT: 9 cases (4.4%)	Exposure to high altitudes for long periods of time, in addition to the use of thermal protection inferior to that used by climbers in winter.	-The medical risks and trauma cases produced at high altitude affected 1% of the participants. -Head injuries and traumas are the most frequent types at high altitude. -Altitude sickness and cold-related injuries are more frequent in summer, during climbing activities.
Chlíbková et al. (2016) [28]	To determine the state of hydration before and after a competition and the incidence of EAH in ultra-endurance athletes.	113 athletes -25 F -88 M	Ultra-endurance in the Czech Republic. (2012–2013) -4 cycle races of 24 h in the mountains. -3 foot races: 2 of 24 h and 1 of 100 km	DH and EAH.	EAH: 13 cases (11.5%) DH: 30 cases (27%)	Loss of sodium in the sweat during the races. Over-ingestion of drinks and greater retention of liquids.	-Incidence of EAH greater than that reported previously in ultra-endurance athletes. -Hyper-hydration before the race did not protect the athletes. -The results obtained indicate that the concentration of sodium [Na+] in the blood is still the only viable way of determining EAH in endurance athletes.
Danz et al. (2016) [13]	To evaluate the rates of EAH in an Ironman competition.	1089 athletes -157 F -932 M	Ironman championships held in Europe (2005–2013)	EAH.	EAH: 115 cases (10.6%) -Mild: 95 cases (8.7%) -Severe: 17 cases (1.6%) -Critical: 3 cases (0.3%)	Association between: -EAH and F -EAH and those that took longer to complete the events.	-EAH has a high incidence among Ironman competitors. -F competitors and those that took ≥9 h seem to be more susceptible to EAH.
Joslin et al. (2016) [29]	To determine the number of medical complications related to EHS and the number of competitors who, for this reason, did not complete the race.	326 athletes	Ultra-marathons of various stages, in the Amazonian jungle, Brazil (2008–2013)	EHS.	Heat related problems: 29 cases (8.9%)	Incorrect acclimatization before the event and inappropriate rest between stages.	Obligatory rests during ultra-endurance competitions in tropical conditions are probably the best way to improve the safety of the athletes and their acclimatization to the heat.
Stuempfle et al. (2015) [30]	To examine the incidence, the seriousness, and the time of appearance of symptoms of GI problems in athletes who complete the event, and in those who do not.	272 athletes -56 F -216 M	Ultra-marathon of 161 km, USA. (2013)	GI illnesses.	GI symptoms: 261 cases (96%) -Nausea: 157 cases (60.3%) -Vomiting: 92 cases (35.4%) -Stomach cramps: 83 cases (31.9%) -Intestinal cramps: 63 cases (24.1%) -Diarrhea: 58 cases (22.2%) -GI hemorrhages: 4 cases (1.5%)	Multifactorial origin, including an altered physiology, mechanical factors, and the intake of water and food before the competition.	-GI symptoms were experienced by most of the runners (96.0%). -The results obtained seem to confirm that GI symptoms are very common during ultra-marathons; in particular, nausea, a key problem that can determine whether or not a competitor can complete the event.
Cairns et al. (2015) [12]	-To examine the incidence of EAH during and after an ultra-marathon. -To evaluate the non-osmotic stimuli with distinct concentrations of arginine and vasopressin in runners suffering hyponatremia.	15 athletes -3 F -12 M	Ultra-endurance, Great North Walk (GNW) 100s, Australia. (2013)	EAH.	EAH: 10 cases (66.7%)	High consumption of alcohol, rise in body weight during the event, low body weight, female sex, slow pace, lack of experience in these competitions.	-EAH incidence of 67% in endurance athletes, which highlights the need to improve the information and education, to minimize the risk of EAH. -The incidence of EAH was greater in F than in M.
Hoffman et al. (2013) [31]	-To analyze cases of EAH. -To define the relationship between [Na+] and changes in body eight. -To examine the interactions between the incidence of EAH, ambient temperature, and hydration state.	887 athletes	WSER ultra-marathon, 161 km, USA. (2009–2012)	DH and EAH.	DH: 164 cases (18.5%) EAH: 101 cases (15.1%)	The ambient temperature and an inverse relationship between [Na+] and the percentage change in body weight.	-The incidence of EAH may be higher in ultra-marathons of 161 km, especially at higher temperatures—when the over-hydration is lower and DH is greater. -Although weight loss does not seem to have an adverse effect on performance, ultra-endurance athletes should not take excessive supplementary Na or drink too much liquid.
Rüst et al. (2012) [32]	To investigate the prevalence of EAH in masculine triathletes competing in the Triple Iron triathlon.	45 M	“Triple Iron” Triathlon, Germany. (2007)	EAH.	EAH: 8 cases (17.8%)	Excessive intake of liquids, more inappropriate secretion of ADH and complications in the mobilization of Na+.	-The prevalence of EAH in this event is greater, based on existing reports on Ironman athletes. -In comparison with marathon runners, the athletes studied here, who compete for >24 h, seem to have a greater risk of developing EAH.
Mexia et al. (2013) [33]	-To evaluate risk factors associated with GI problems. -To determine the use of preventative measures. -To compare the findings with those of previous years regarding GI problems and evaluate risk and protective factors.	11721 athletes	“Birkebeinerrittet” mountain bike race, Norway. (2010)	GI illnesses.	Diarrhea: 572 cases (4.9%)	Exposure to mud in the face or mouth during the competition. The absence of a mudguard increased the risk.	-Exposure to mud with fecal contamination is a risk factor. The environmental measures that could reduce this exposure include the elimination of grazing livestock from close to the track and the reduction in the size of muddy areas. -Improvement of preventative strategies.
Hoffman et al. (2012) [34]	-To determine the incidence of EAH, the associated biochemical parameters, and risk factors. -To check if there is an association between the [Na+] in the blood after the race and the changes in body mass of the participants.	47 athletes	Ultramarathon WSER de 161 Km, EEUU. (2009)	EAH and associated nausea	EAH: 14 cases (30%) Nausea: 22 cases (46.8%)	It is associated with DH, since it suggests that the loss of sodium can be a factor in the development of EAH during events of long duration at high temperatures.	-EAH may be a common condition (incidence of 30%) among the finalists of an ultra-marathon. -It is not unusual for athletes with EAH to suffer DH. -The development of EAH was not related to age, sex or the time taken to complete the event, but the athletes with EAH had participated in fewer ultra- marathons.
Hoffman et al. (2011) [35]	To explore demographic characteristics and problems that affect the sport performance during an ultra-marathon.	489 athletes	WSER ultra-marathon (161 km) and Vermont 100, North America. (2009)	Medicinal- nutritional problems that prevented 232 participants from completing the event	Nausea and/or vomiting: 92 cases (39.6%) DH: 11 cases (4.7%) Inadequately heat acclimatization: 65 cases (28.1%)	The ambient temperature, the amount of training, or experience in successfully completing this type of event.	-More than half of the ultra-marathon runners suffered a problem that prevented them from finishing the competition and led to an average of 21 days of recovery and preparation for later races. -Nausea and/or vomiting are an important problem that limits the performance of participants in ultra-marathons. -The athletes affected by nausea and/or vomiting took longer to complete the race than those not suffering these symptoms.
Bruso et al. (2010) [36]	To explore risk factors associated with development of EAH and rhabdomyolysis during an ultra-marathon.	400 athletes	WSER ultra-marathon (161 km), USA. (2009)	EAH.	EAH: 5 cases (1.25%)	The causes of the appearance of EAH in this competition have not been established.	-One consistent characteristic was that all 5 individuals affected received a normal saline solution, intravenously, as part of their initial treatment. -Extreme precaution is recommended in the use of normal saline solution, given intravenously, especially if there are symptoms of cerebral encephalopathy, which could be worsened by this action.
Griffiths et al. (2010) [37]	To investigate the causes of an outbreak of diarrhea during a mountain bike competition.	347 athletes -45 F -299 M -3 unspecified	Mountain bike competition, UK. (2008)	GI illnesses.	GI illnesses: 161 cases (46.5%) -Diarrhea: 151 cases (43.5%) -Abdominal pain: 131 cases (37.7%) -Nausea: 91 cases (26.2%) -Vomiting: 31 cases (8.9%) -Blood in feces: 15 cases (4.3%)	Outbreak caused by Campylobacter and spread by the accidental ingestion of mud, as well as by the use of water contaminated in the same way to fill the water bottles.	-The successful use of the Internet, to carry out a quick and efficient investigation into an outbreak of diarrhea and other symptoms associated with a mountain bike competition, was demonstrated. -The microbiological risks are an inherent part of this type of sport and the hygiene measures must be very strict to minimize the risk of infection.
Kipps et al. (2011) [38]	To determine the incidence of EAH in the runners who participate in a marathon.	88 athletes	London marathon, United Kingdom. (2003)	EAH.	EAH: 11 cases (12.5%)	Some runners probably started the race in a state of hyperhydration.	-A significant proportion (12.5%) of the participants developed asymptomatic EAH after completing the race. Although they consumed more fluids, the ingestion of fluids was not related to the increase in body weight. -4 of the 11 runners with hyponatremia lost weight during the race, reinforcing the idea of an additional factor in the development of EAH.
Chlíbková et al. (2015) [39]	-Identification of athletes that develop EAH and rhabdomyolysis simultaneously. -To study hyponatremic and normonatremic athletes and try to find biochemical factors common to both EAH and rhabdomyolysis.	145 athletes	7 ultra-endurance races in the Czech Republic (2012–2013): -5 cycle races (24 h, mountain and trilogy) -2 foot races (24 h and 100 km)	EAH (113 completed the competition)	EAH: 13 cases (11.5%)	Secretion of arginine and vasopressin (antidiuretic hormone), and loss of liquid from muscle.	-Rhabdomyolysis induced by the exercise was more frequent in hyponatremic athletes than in normonatremic athletes. -The incidence of rhabdomyolysis tended to be greater among ultra-runners than among mountain cyclists. -The mechanism that could explain the relationship between rhabdomyolysis and EAH was not determined.

M = male; F = female; GI: gastrointestinal; EAH: exercise-associated hyponatremia; EHS: heat stroke by exertion; DH: dehydration; HT: hypothermia.