Swimming in ice cold water

A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 3: Heat and cold tolerance during exercise

In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.

[Ice Swimming]

Ice Swimming Abstract: Just a few years ago, no one could imagine that ice swimming could evolve into a competitive sport. In the past, people swimming in ice-cold water were called madmen and, at best, were studied as scientific objects. Today regular competitions in ice swimming over different distances (ice mile, ice km, and shorter distances such as 50m, 100m, and 200m), and different disciplines are organized (freestyle, breaststroke, backstroke, butterfly). National championships, as well as continental and world championships, are also held, with new records set regularly. In this overview, we summarize the historical development of ice swimming up to a competitive sport and explore the risks in this nascent sports discipline.

Influence of water-based exercise on energy intake, appetite, and appetite-related hormones in adults: A systematic review and meta-analysis

Single bouts of land-based exercise suppress appetite and do not typically alter energy intake in the short-term, whereas it has been suggested that water-based exercise may evoke orexigenic effects. The primary aim was to systematically review the available literature investigating the influence of water-based exercise on energy intake in adults (PROSPERO ID number CRD42022314349). PubMed, Medline, Sport-Discus, Academic Search Complete, CINAHL and Public Health Database were searched for peer-reviewed articles published in English from 1900 to May 2022. Included studies implemented a water-based exercise intervention versus a control or comparator. Risk of bias was assessed using the revised Cochrane 'Risk of bias tool for randomised trials' (RoB 2.0). We identified eight acute (same day) exercise studies which met the inclusion criteria. Meta-analysis was performed using a fixed effects generic inverse variance method on energy intake (8 studies (water versus control), 5 studies (water versus land) and 2 studies (water at two different temperatures)). Appetite and appetite-related hormones are also examined but high heterogeneity did not allow a meta-analysis of these outcome measures. We identified one chronic exercise training study which met the inclusion criteria with findings discussed narratively. Meta-analysis revealed that a single bout of exercise in water increased ad-libitum energy intake compared to a non-exercise control (mean difference [95% CI]: 330 [118, 542] kJ, P = 0.002). No difference in ad libitum energy intake was identified between water and land-based exercise (78 [-176, 334] kJ, P = 0.55). Exercising in cold water (18-20 °C) increased energy intake to a greater extent than neutral water (27-33 °C) temperature (719 [222, 1215] kJ; P < 0.005). The one eligible 12-week study did not assess whether water-based exercise influenced energy intake but did find that cycling and swimming did not alter fasting plasma concentrations of total ghrelin, insulin, leptin or total PYY but contributed to body mass loss 87.3 (5.2) to 85.9 (5.0) kg and 88.9 (4.9) to 86.4 (4.5) kg (P < 0.05) respectively. To conclude, if body mass management is a person's primary focus, they should be mindful of the tendency to eat more in the hours after a water-based exercise session, particularly when the water temperature is cold (18-20 °C).

Practicing Sport in Cold Environments: Practical Recommendations to Improve Sport Performance and Reduce Negative Health Outcomes

Although not a barrier to perform sport, cold weather environments (low ambient temperature, high wind speeds, and increased precipitation, i.e., rain/water/snow) may influence sport performance. Despite the obvious requirement for practical recommendations and guidelines to better facilitate training and competition in such cold environments, the current scientific evidence-base is lacking. Nonetheless, this review summarizes the current available knowledge specifically related to the physiological impact of cold exposure, in an attempt to provide practitioners and coaches alike with practical recommendations to minimize any potential negative performance effects, mitigate health issues, and best optimize athlete preparation across various sporting disciplines. Herein, the review is split into sections which explore some of the key physiological effects of cold exposure on performance (i.e., endurance exercise capacity and explosive athletic power), potential health issues (short-term and long-term), and what is currently known with regard to best preparation or mitigation strategies considered to negate the potential negative effects of cold on performance. Specific focus is given to "winter" sports that are usually completed in cold environments and practical recommendations for physical preparation.

Influence of Anthropometric Characteristics on Ice Swimming Performance-The IISA Ice Mile and Ice Km

Ice swimming following the rules of IISA (International Ice Swimming Association) is a recent sports discipline starting in 2009. Since then, hundreds of athletes have completed an Ice Mile or an Ice Km in water colder than 5 °C. This study aimed to expand our knowledge about swimmers completing an Ice Mile or an Ice Km regarding the influence of anthropometric characteristics (i.e., body mass, body height, and body mass index, BMI) on performance. We analyzed data from 957 swimmers in the Ice Km (590 men and 367 women) and 585 swimmers in the Ice Mile (334 men and 251 women). No differences were found for anthropometric characteristics between swimmers completing an Ice Mile and an Ice Km although water temperatures and wind chill were lower in the Ice Km than in the Ice Mile. Men were faster than women in both the Ice Mile and Ice Km. Swimming speed decreased significantly with increasing age, body mass, and BMI in both women and men in both the Ice Mile and Ice Km. Body height was positively correlated to swimming speed in women in the Ice Km. Air temperature was significantly and negatively related to swimming speed in the Ice Km but not in the Ice Mile. Water temperature was not associated with swimming speed in men in both the Ice Mile and Ice Km but significantly and negatively in women in Ice Km. In summary, swimmers intending to complete an Ice Mile or an Ice Km do not need to have a high body mass and/or a high BMI to swim these distances fast.

Cold Water Swimming-Benefits and Risks: A Narrative Review

Cold water swimming (winter or ice swimming) has a long tradition in northern countries. Until a few years ago, ice swimming was practiced by very few extreme athletes. For some years now, ice swimming has been held as competitions in ice-cold water (colder than 5 °C). The aim of this overview is to present the current status of benefits and risks for swimming in cold water. When cold water swimming is practiced by experienced people with good health in a regular, graded and adjusted mode, it appears to bring health benefits. However, there is a risk of death in unfamiliar people, either due to the initial neurogenic cold shock response or due to a progressive decrease in swimming efficiency or hypothermia.

Characteristics and Challenges of Open-Water Swimming Performance: A Review

CONTEXT

Although the popularity of open-water swimming (OWS) events has significantly increased in the last decades, specific studies regarding performance of elite or age-group athletes in these events are scarce.

PURPOSE

To analyze the existing literature on OWS.

METHODS

Relevant literature was located via computer-generated citations. During August 2016, online computer searches on PubMed and Scopus databases were conducted to locate published research.

RESULTS

The number of participants in ultraendurance swimming events has substantially increased in the last 10 y. In elite athletes there is a higher overall competitive level of women than of men. The body composition of female athletes (different percentage and distribution of fat tissue) shows several advantages (more buoyancy and less drag) in aquatic conditions that determine the small difference between males and females. The main physiological characteristics of open-water swimmers (OW swimmers) are the ability to swim at high percentage of [Formula: see text] (80-90%) for many hours. Furthermore, to sustain high velocity for many hours, endurance swimmers need a high propelling efficiency and a low energy cost.

CONCLUSION

Open-water races may be characterized by extreme environmental conditions (water temperature, tides, currents, and waves) that have an overall impact on performance, influencing tactics and pacing. Future studies are needed to study OWS in both training and competition.

Swim performance and thermoregulatory effects of wearing clothing in a simulated cold-water survival situation

PURPOSE

Accidental cold-water immersion (CWI) impairs swim performance, increases drowning risk and often occurs whilst clothed. The impact of clothing on thermoregulation and swim performance during CWI was explored with the view of making recommendations on whether swimming is viable for self-rescue; contrary to the traditional recommendations.

METHOD

Ten unhabituated males (age 24 (4) years; height 1.80 (0.08) m; mass 78.50 (10.93) kg; body composition 14.8 (3.4) fat %) completed four separate CWIs in 12 °C water. They either rested clothed or naked (i.e. wearing a bathing costume) or swum self-paced clothed or naked for up to 1 h. Swim speed, distance covered, oxygen consumption and thermal responses (rectal temperature (T re), mean skin temperature (T msk) and mean body temperature T b) were measured.

RESULTS

When clothed, participants swum at a slower pace and for a significantly shorter distance (815 (482) m, 39 (19) min) compared to when naked (1264 (564) m, 52 (18) min), but had a similar oxygen consumption indicating clothing made them less efficient. Swimming accelerated the rate of T msk and T b cooling and wearing clothing partially attenuated this drop. The impairment to swimming performance caused by clothing was greater than the thermal benefit it provided; participants withdrew due to exhaustion before hypothermia developed.

CONCLUSION

Swimming is a viable self-rescue method in 12 °C water, however, clothing impairs swimming capability. Self-rescue swimming could be considered before clinical hypothermia sets in for the majority of individuals. These suggestions must be tested for the wider population.

The effect of cold water endurance swimming on core temperature in aspiring English Channel swimmers

Background

The purpose of this study was to determine if cold water swimmers (CWS) developed hypothermia over a 6-h cold water endurance swim and whether body composition, stroke rate (SR) or personal characteristics correlated with core temperature (TC) change. Nine experienced male and female CWS who were aspiring English Channel (EC) swimmers volunteered to participate. Subjects aimed to complete their 6-h EC qualifying swim (water 15–15.8 °C/air 15–25 °C) while researchers intermittently monitored TC and SR. Data obtained included anthropometry (height, mass, segmental body composition), training volume and EC completion.

Results

Of the nine swimmers who volunteered, all successfully completed their EC qualifying swim. Six CWS had complete data included in analysis. One CWS demonstrated hypothermia (34.8 °C) at 6-h. TC rate of decline was slower in the first 3 h (−0.06 °C/hr) compared to the last 3 h (−0.36 °C/hr) of the swim. Older age was significantly correlated to TC change (r = −0.901, p < 0.05) and SR change (r = −0.915, p < 0.05). Absolute and percentage body fat (BF) were not significantly associated with higher TC. Mean SR over the 6-h swim was 57.8 spm (range 48–73 spm), and a significant (p < 0.05) decline in SR was observed over the 6 h (−9.7 %). A strong, positive correlation was found between SR change between 3 and 6 h and TC over the 6 h (r = 0.840, p < 0.05) and TC from 3–6 h (r = 0.827, p < 0.05). Seven of the nine participants (77.8 %) in this study successfully completed the EC crossing. Successful EC swimmers swam in the pool and open water (OW); however, they swam significantly [t (7) = −2.433, p < 0.05] more kilometres (M = 19.09 km/wk ± 5.55) in OW than unsuccessful (M = 9 km/wk ± 1.41) EC swimmers. There was a significant relationship between EC crossing time and height (r = −0.817, p < 0.05), but no other variables and EC crossing time.

Conclusions

Cold water endurance swim (CWES) of 6-h duration at 15–16 °C resulted in TC reduction in the majority of swimmers regardless of anthropometry. More research is required to determine why some CWS are able to maintain their TC throughout a CWES. Our results indicate that older swimmers are at greater risk of developing hypothermia, and that SR decline is an indicator of TC decline. Our results also suggest that OW swimming training combined with pool training is important for EC swim success.

Ice swimming - 'Ice Mile' and '1 km Ice event'

Background

Ice swimming for 1 mile and 1 km is a new discipline in open-water swimming since 2009. This study examined female and male performances in swimming 1 mile (‘Ice Mile’) and 1 km (‘1 km Ice event’) in water of 5 °C or colder between 2009 and 2015 with the hypothesis that women would be faster than men.

Methods

Between 2009 and 2015, 113 men and 38 women completed one ‘Ice Mile’ and 26 men and 13 completed one ‘1 km Ice event’ in water colder than +5 °C following the rules of International Ice Swimming Association (IISA). Differences in performance between women and men were determined. Sex difference (%) was calculated using the equation ([time for women] – [time for men]/[time for men] × 100). For ‘Ice Mile’, a mixed-effects regression model with interaction analyses was used to investigate the influence of sex and environmental conditions on swimming speed. The association between water temperature and swimming speed was assessed using Pearson correlation analyses.

Results

For ‘Ice Mile’ and ‘1 km Ice event’, the best men were faster than the best women. In ‘Ice Mile’, calendar year, number of attempts, water temperature and wind chill showed no association with swimming speed for both women and men. For both women and men, water temperature was not correlated to swimming speed in both ‘Ice Mile’ and ‘1 km Ice event’.

Conclusions

In water colder than 5 °C, men were faster than women in ‘Ice Mile’ and ‘1 km Ice event’. Water temperature showed no correlation to swimming speed.

Ice swimming and changes in body core temperature: a case study

Introduction

‘Ice Mile’ swimming is a new discipline in open-water swimming introduced in 2009. This case study investigated changes in body core temperature during preparation for and completion of two official ‘Ice Miles’, defined as swimming 1.609 km in water of 5°C or colder, in one swimmer.

Case description

One experienced ice swimmer (56 years old, 110.2 kg body mass, 1.76 m body height, BMI of 35.6 kg/m², 44.8% body fat) recorded data including time, distance and body core temperature from 65 training units and two ‘Ice Miles’.

Discussion and evaluation

During training and the ‘Ice Miles’, body core temperature was measured using a thermoelectric probe before, during and after swimming. During trainings and the ‘Ice Miles’, body core temperature increased after start, dropped during swimming but was lowest during recovery. During training, body core temperature at start was the only predictor (ß = −0.233, p = 0.025) for the increase in body core temperature. Water temperature (ß = 0.07, p = 0.006) and body core temperature at start (ß = −0.90, p = 0.006) explained 61% of the variance for the non-significant decrease in body core temperature. Water temperature (ß = 0.077, p = 0.0059) and body core temperature at finish (ß = 0.444, p = 0.02) were the most important predictors for the lowest body core temperature. In ‘Ice Miles’, body core temperature was highest ~6–18 min after the start (38.3–38.4°C), dropped during swimming by 1.7°C to ~36.5°C and was lowest ~40–56 min after finish. The lowest body core temperature (34.5–35.0°C) was achieved ~100 min after start.

Conclusions

In an experienced ice swimmer with a high BMI (>35 kg/m²) and a high percent body fat (~45%), body core temperature decreased by 1.7°C while swimming and by 3.2–3.7°C after the swim to reach the lowest temperature in an official ‘Ice Mile’. The swimmer suffered no hypothermia during ice swimming, but body core temperature dropped to <36°C after ice swimming. Future athletes intending to swim an ‘Ice Mile’ should be aware that a large body fat prevents from suffering hypothermia during ice swimming, but not after ice swimming.

Women outperform men in ultradistance swimming: the Manhattan Island Marathon Swim from 1983 to 2013

PURPOSE

Recent studies suggested that women's and men's ultraswim performances may be similar for distances of ≈ 35 km. The current study investigated both the gender difference and the age of peak ultraswim performance between 1983 and 203 at the 46-km Manhattan Island Marathon Swim with water temperatures < 20°C.

METHODS

Changes in race times and gender difference in 551 male and 237 female finishers were investigated using linear-, nonlinear, and hierarchical multilevel-regression analyses.

RESULTS

The top 19 race times ever were significantly (P < .0001) lower for women (371 ± 11 min) than for men (424 ± 9 min). Race times of the annual 3 fastest women and men did not differ between genders and remained stable across years. The age of the annual 3 fastest swimmers increased from 28 ± 4 y (1983) to 38 ± 6 y (2013; r² = .06, P = .03) in women and from 23 ± 4 y (1984) to 42 ± 8 y (2013; r² = .19, P < .0001 )in men.

CONCLUSION

The best women were ≈12 - 14% faster than the men in a 46-km open-water ultradistance race with temperatures < 20°C. The maturity of ultradistance swimmers has changed during the last decades, with the fastest swimmers becoming older across the years.

Changes in sex difference in swimming speed in finalists at FINA World Championships and the Olympic Games from 1992 to 2013

Background

This study investigated swimming speeds and sex differences of finalists competing at the Olympic Games (i.e. 624 female and 672 male athletes) and FINA World Championships (i.e. 990 women and 1008 men) between 1992 and 2013.

Methods

Linear, non-linear and multi-level regression models were used to investigate changes in swimming speeds and sex differences for champions and finalists.

Results

Regarding finalists in FINA World Championships and Olympic Games, swimming speed increased linearly in both women and men in all disciplines and race distances. Male world champions’ swimming speed remained stable in 200 m butterfly, 400 m, 800 m and 1,500 m freestyle. Considering women, swimming speed remained unchanged in 50 m and 400 m freestyle. In the Olympic Games, swimming speed of male champions remained unchanged in 200 m breaststroke, 50 m, 400 m, 800 m and 1,500 m freestyle. Female Olympic champions’ swimming speed remained stable in 100 m and 200 m backstroke, 100 m butterfly, 200 m individual medley, 50 m and 200 m freestyle. Evaluating sex differences between finalists in FINA World Championships, results showed a linear decrease in 100 m breaststroke and 200 m butterfly and a non-linear increase in 100 m backstroke. In finals at the Olympic Games, the sex difference decreased linearly for 100 m backstroke, 400 m and 800 m freestyle. However, a linear increase for 200 m butterfly can be reported. Considering Olympic and world champions, the sex difference remained stable in all disciplines and race distances.

Conclusion

Swimming speed of the finalists at the Olympic Games and FINA World Championships increased linearly. The top annual female swimmers increased swimming speed rather at longer race distances (i.e. 800 m and 1,500 m freestyle, 200 m butterfly, and 400 m individual medley), whereas the top annual male swimmers increased it rather at shorter race distances (i.e. 100 m and 200 m freestyle, 100 m butterfly, and 100 m breaststroke). Sex difference in swimming was unchanged in Olympic and world champions. Finalists and champions at the Olympic Games and FINA World Championships reduced the sex difference with increasing race distance.

Analysis of sex differences in open-water ultra-distance swimming performances in the FINA World Cup races in 5 km, 10 km and 25 km from 2000 to 2012

BACKGROUND

The present study investigated the changes in swimming speeds and sex differences for elite male and female swimmers competing in 5 km, 10 km and 25 km open-water FINA World Cup races held between 2000 and 2012.

METHODS

The changes in swimming speeds and sex differences across years were analysed using linear, non-linear, and multi-level regression analyses for the annual fastest and the annual ten fastest competitors.

RESULTS

For the annual fastest, swimming speed remained stable for men and women in 5 km (5.50 ± 0.21 and 5.08 ± 0.19 km/h, respectively), in 10 km (5.38 ± 0.21 and 5.05 ± 0.26 km/h, respectively) and in 25 km (5.03 ± 0.32 and 4.58 ± 0.27 km/h, respectively). In the annual ten fastest, swimming speed remained constant in 5 km in women (5.02 ± 0.19 km/h) but decreased significantly and linearly in men from 5.42 ± 0.03 km/h to 5.39 ± 0.02 km/h. In 10 km, swimming speed increased significantly and linearly in women from 4.75 ± 0.01 km/h to 5.74 ± 0.01 km/h but remained stable in men at 5.36 ± 0.21 km/h. In 25 km, swimming speed decreased significantly and linearly in women from 4.60 ± 0.06 km/h to 4.44 ± 0.08 km/h but remained unchanged at 4.93 ± 0.34 km/h in men. For the annual fastest, the sex difference in swimming speed remained unchanged in 5 km (7.6 ± 3.0%), 10 km (6.1 ± 2.5%) and 25 km (9.0 ± 3.7%). For the annual ten fastest, the sex difference remained stable in 5 km at 7.6 ± 0.6%, decreased significantly and linearly in 10 km from 7.7 ± 0.7% to 1.2 ± 0.3% and increased significantly and linearly from 4.7 ± 1.4% to 9.6 ± 1.5% in 25 km.

CONCLUSIONS

To summarize, elite female open-water ultra-distance swimmers improved in 10 km but impaired in 25 km leading to a linear decrease in sex difference in 10 km and a linear increase in sex difference in 25 km. The linear changes in sex differences suggest that women will improve in the near future in 10 km, but not in 25 km.

Analysis of 10 km swimming performance of elite male and female open-water swimmers

This study investigated trends in performance and sex difference in swimming speed of elite open-water swimmers at FINA 10 km competitions (i.e. World Cup races, European Championships, World Championships and Olympic Games). Swimming speed and sex difference in swimming speed of the fastest and the top ten women and men per event competing at 10 km open-water races between 2008 and 2012 were analysed using single and multi-level regression analyses. A total of 2,591 swimmers (i.e. 1,120 women and 1,471 men) finished 47 races. Swimming speed of the fastest women (1.35 ± 0.9 m/s) and men (1.45 ± 0.10 m/s) showed no changes across years. The mean sex difference in swimming speed for the fastest swimmers was 6.8 ± 2.5%. Swimming speed of the top ten female swimmers per event was 1.34 ± 0.09 m/s and remained stable across the years. The top ten male swimmers per event showed a significant decrease in swimming speed over time, even though swimming speed in the first race (i.e. January 2008, 1.40 ± 0.0 m/s) was slower than the swimming speed in the last race (i.e. October 2012, 1.50 ± 0.0 m/s) (P < 0.05). To summarize, swimming performances remained stable for the fastest elite open-water swimmers at 10 km FINA competitions between 2008 and 2012, while performances of the top ten men tended to decrease. The sex difference in swimming speed in elite ultra-swimmers (~7%) appeared smaller compared to other ultra-distance disciplines such as running. Further studies should examine how body shape and physiology of elite open-water ultra-distance swimmers influence performances.

Sex difference in open-water ultra-swim performance in the longest freshwater lake swim in Europe

This study examined participation and performance trends in the 26.4-km open-water ultra-swim "Marathon Swim in Lake Zurich," Switzerland. A total of 461 athletes (157 women and 304 men) finished the race between 1987 and 2011. The mean age of the finishers during the studied period was 32.0 ± 6.5 years for men and 30.9 ± 7.2 years for women. The mean age of finishers and the age of winners increased significantly across years for both sexes (p < 0.01). The winner times were significantly lower for men (403 ± 43 minutes) compared with women (452 ± 63 minutes) (p < 0.01). In contrast, the mean swimming time of the finishers did not differ between men (530 ± 39 minutes) and women (567 ± 71 minutes) (p > 0.05). The swimming time performance remained stable (p > 0.05) for both sexes across years. A higher age was associated with an increased risk for not finishing the race (odds ratio = 0.93, p = 0.045). Swim time was negatively associated with water temperature in the top 3 swimmers (ß = -9.87, p = 0.025). These results show that open-water ultra-swimming performance of elite swimmers over 26.4 km in a freshwater lake is affected by age, sex, and water temperature. The sex difference in open-water ultra-swimming performance (approximately 11.5%) remained unchanged these last 25 years. It seems unlikely that elite female swimmers will achieve the same performance of elite male swimmers competing in open-water ultra-swimming in water of approximately 20 °C. Anthropometric and physiological characteristics such as skeletal muscle mass and thermoregulation need additional investigations in female and male open-water ultra-swimmers.

Age and gender interactions in short distance triathlon performance

This study investigated the participation and performance trends as well as the age and gender interaction at the Olympic distance 'Zürich Triathlon' (1.5 km swim, 40 km cycle and 10 km run) from 2000 to 2010 in 7,939 total finishers (1,666 females and 6,273 males). Female triathletes aged from 40 to 54 years significantly (P < 0.05) increased their participation while the participation of younger females and males remained stable. Males of 50-54 years of age and females of 45-49 years of age improved their total race time. For elite top five overall triathletes, mean gender differences in swimming, cycling, running and overall race time were 15.2 ± 4.6%, 13.4 ± 2.3%, 17.1 ± 2.5%, and 14.8 ± 1.8%, respectively. For both elite and age group athletes, the gender difference in cycling time was significantly (P <0.001) lower than for swimming and running. The gender difference in overall Olympic distance triathlon performance increased after the age of 35 years, which appeared earlier compared to long distance triathlon as suggested by previous studies. Future investigations should compare gender difference in performance for different endurance events across age to confirm a possible effect of exercise duration on gender difference with advancing age.

Changes in body core and body surface temperatures during prolonged swimming in water of 10°C-a case report

BACKGROUND

This case report describes an experienced open-water ultra-endurance athlete swimming in water of 9.9°C for 6 h and 2 min.

METHODS

Before the swim, anthropometric characteristics such as body mass, body height, skinfold thicknesses, and body fat were determined. During and after the swim, body core (rectum) and body surface (forearm and calf) temperatures were continuously recorded.

RESULTS

The swimmer (53 years old, 110.5 kg body mass, 1.76 m body height, 34.9% body fat, and a body mass index of 35.7 kg/m2) achieved a total distance of 15 km while swimming at a mean speed of 2.48 km/h, equal to 0.69 m/s, in water of 9.9°C. Body core temperature was at 37.8°C before the swim, increased to a maximum of 38.1°C after approximately 20 min of swimming, and then decreased continuously to 36.3°C upon finishing the swim. The lowest body core temperature was 36.0°C between 35 and 60 min after finishing the swim. Sixty minutes after the swim, the body core temperature continuously rose to 36.5°C where it remained. At the forearm, the temperature dropped to 19.6°C after approximately 36 min of swimming and decreased to 19.4°C by the end of the swim. The lowest temperature at the forearm was 17.6°C measured at approximately 47 min before the athlete stopped swimming. At the calf, the temperature dropped to 13.0°C after approximately 24 min of swimming and decreased to 11.9°C at the end of the swim. The lowest temperature measured at the calf was 11.1°C approximately 108 min after the start. In both the forearm and the calf, the skin temperature continuously increased after the swim.

CONCLUSIONS

This case report shows that (1) it is possible to swim for 6 h in water of 9.9°C and that (2) the athlete did not suffer from hypothermia under these circumstances. The high body mass index, high body fat, previous experience, and specific preparation of the swimmer are the most probable explanations for these findings.

Best performances by men and women open-water swimmers during the 'English Channel Swim' from 1900 to 2010

Little research has examined ultra-endurance swimming performances. The 'English Channel Swim', where swimmers have to cover a distance of 32 km between England and France represents a unique long-distance, open-water, sea-swimming challenge, and each year swimmers from all over the world try to succeed in this challenge. The best times in minutes and the nationality of successful men and women swimmers were analysed from 1900 to 2010. A total of 1,533 swimmers (455 women and 1,078 men) from more than 40 countries have successfully completed the 'English Channel Swim'. Great Britain was the country most represented, with 38% of the total, followed by the United States with 20%. Swim speed has increased progressively for both sexes (P < 0.001) but was lower for women than for men (0.68 ± 0.15 m · s⁻¹ vs 0.71 ± 0.16 m · s⁻¹ respectively, P < 0.01). However, the best annual performances did not differ between the sexes (men: 0.89 ± 0.20 m · s⁻¹; women: 0.84 ± 0.18 m · s⁻¹, P > 0.05). The results suggest that the performance of women open-water ultra-distance swimmers may be similar to that of men. Further studies investigating anthropometrical and physiological characteristics of open-water ultra-swimmers are needed to compare men's and women's open-water ultra-swim performances.

Central European triathletes dominate Double Iron ultratriathlon - analysis of participation and performance 1985-2011

Background

A recent study showed that European triathletes performed faster in Double Iron ultratriathlons than North American athletes. The present study analyzed triathletes participating in Double Iron ultratriathlons to determine the origin of the fastest Double Iron ultratriathletes, focusing on European countries.

Methods

Participation and performance trends of finishers in Double Iron ultratriathlons from 1985–2011 of the different countries were investigated. Additionally, the performance trends of the top three women and men overall from 2001–2011 were analyzed.

Results

A total of 1490 finishers originated from 24 different European countries and the United States. The number of European triathletes increased for both women (r² = 0.56; P < 0.01) and men (r² = 0.63; P < 0.01). The number of the North American triathletes increased for women (r² = 0.25; P < 0.01), but not for men (r² = 0.02; P > 0.05). Hungarian triathletes showed a significant improvement in both overall race times and in cycling split times, Swiss triathletes improved both their swim and run times, and French triathletes improved their swim times.

Conclusion

Men and women triathletes from Central European countries such as France, Germany, Switzerland, and Hungary improved Double Iron ultratriathlon overall race times and split times during the 26-year period. The reasons might be the social and economic factors required to be able to participate in such an expensive and lavish race. Also, a favorable climate may provide the ideal conditions for successful training. Future studies need to investigate the motivational aspects of European ultraendurance athletes.

Speed during Training and Anthropometric Measures in Relation to Race Performance by Male and Female Open-Water Ultra-Endurance Swimmers

The relationship of anthropometric and training characteristics with race time were investigated in 39 male and 24 female open-water ultra-endurance swimmers in a 26.4 km open-water ultra-swim, using bi- and multivariate analyses. For the men, body height, Body Mass Index, length of arm, and swimming speed during training were related to race time in the bivariate analysis. For the women, swimming speed during training was associated with performance in the bivariate analysis. In the multivariate analysis for the men, Body Mass Index and swimming speed during training were related to race time.