Core Temperature in Triathletes during Swimming with Wetsuit in 10 °C Cold Water

Freshwater Wild Swimming, Health and Well-Being: Understanding the Importance of Place and Risk

Spending time in or around bodies of water or ‘blue spaces’ can benefit human health and well-being. A growing body of evidence suggests immersion in blue space, e.g., participating in ‘wild’ swimming, can be particularly beneficial for both physical and mental health. To date, wild swimming and health research has primarily focused on the experience of individuals who swim in the sea. Empirical studies of the health-promoting potential of swimming in freshwater environments, such as lochs and lakes, are lacking, despite the popularity of this practice in many countries and the vastly different physical and hydrological properties of freshwater and coastal environments. The aim of this study was to explore the relationship between loch (lake) swimming and health and well-being for adults living in Scotland and determine the importance of perceptions of place and risk in this relationship. Semi-structured interviews were conducted with twelve wild swimmers who regularly swim in lochs in Scotland. Interview data were analysed thematically using Nvivo. The findings suggest loch swimming has a variety of health and well-being benefits that can be categorised over three domains of health: physical, mental and social. Of these domains, mental health benefits e.g., mindfulness promotion, resilience building and increasing one’s ability to listen to their body, were particularly prominent. Our findings also highlight important physical and hydrological characteristics of loch environments, e.g., calm water conditions (relative to the sea), which contribute to positive wild swimming experiences. Finally, the perceived risks of loch swimming and mitigation strategies for these risks are established. Collectively, our findings further support the notion that wild swimming is a unique health-promoting practice. Our findings also highlight differences (in terms of experience and perceived risk) between swimming in freshwater and coastal environments, which can inform public health and water management policy.

Wetsuit Use During Open Water Swimming. Does It "Suit" Everybody? A Narrative Review

PURPOSE

Although wearing a wetsuit while swimming, when permitted, is primarily for safety reasons (ie, to protect against hypothermia), changes in buoyancy, biomechanics, and exercise performance have been reported. This narrative review covers the benefits of different wetsuit models on performance in swimming and triathlon.

METHODS

A computer search of online databases was conducted to locate relevant published research until March 2021. After the screening process, 17 studies were selected for analysis.

RESULTS

Most of the selected studies involved pool swimmers or triathletes completing short or middle distances in a pool while using a full or a long sleeveless wetsuit. Swimming with wetsuit elicited significant improvements in performance (maximum 11%), mainly by decreasing drag and energy cost, by increasing buoyancy, and by affecting technique. Different rates of change in each factor were found according to swimming ability and wetsuit model. In addition, wearing a wetsuit was often rated as uncomfortable by athletes.

CONCLUSIONS

Although improvement in swimming performance by wearing a wetsuit has been reported in the literature, the amplitude of the improvement remains questionable. The enhancement in swimming performance is attributable merely to improvements in propulsion proficiency and buoyancy, as well as a reduction in drag. The extent to which athletes are familiar with the use of a wetsuit, their swimming ability, and the wetsuit model may play important roles in this improvement. More studies simulating competition and comparing elite versus nonelite athletes are needed.

Core Temperature during Cold-Water Triathlon Swimming

Triathlon and other endurance races have grown in popularity. Although participants are generally fit and presumably healthy, there is measurable morbidity and mortality associated with participation. In triathlon, most deaths occur during the swim leg, and more insight into risk factors, such as hypothermia, is warranted. In this study, we measured the core temperature of 51 participants who ingested temperature sensor capsules before the swim leg of a full-distance triathlon. The water temperature was 14.4–16.4 °C, and the subjects wore wetsuits. One subject with a low body mass index and a long swim time experienced hypothermia (<35 °C). Among the remaining subjects, we found no association between core temperature and swim time, body mass index, or sex. To conclude, the present study indicates that during the swim leg of a full-distance triathlon in water temperatures ≈ 15–16 °C, subjects with a low body mass index and long swim times may be at risk of hypothermia even when wearing wetsuits.

Does Cold-Water Endurance Swimming Affect Pulmonary Function in Healthy Adults?

The acute effects of cold-water endurance swimming on the respiratory system have received little attention. We investigated pulmonary responses to cold-water endurance swimming in healthy recreational triathletes. Pulmonary function, alveolar diffusing capacity (DL_CO), fractional exhaled nitric oxide (FE_NO) and arterial oxygen saturation by pulse oximetry (SpO₂) were assessed in 19 healthy adults one hour before and 2.5 h after a cold-water (mean ± SD, 10 ± 0.9 °C) swim trial (62 ± 27 min). In addition, 12 out of the 19 participants measured pulmonary function, forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁) 3, 10, 20 and 45 min post-swim by maximal expiratory flow volume loops and DL_CO by the single breath technique. FVC and FEV₁ were significantly reduced 3 min post-swim (p = 0.02) (p = 0.04), respectively, and five of 12 participants (42%) experienced exercise-induced bronchoconstriction (EIB), defined as a ≥ 10% drop in FEV₁. No significant changes were observed in pulmonary function 2.5 h post-swim. However, mean FE_NO and DL_CO were significantly reduced by 7.1% and 8.1% (p = 0.01) and (p < 0.001), respectively, 2.5 h post-swim, accompanied by a 2.5% drop (p < 0.001) in SpO₂. The absolute change in DL_CO correlated significantly with the absolute decline in core temperature (r = 0.52; p = 0.02). Conclusion: Cold-water endurance swimming may affect the lungs in healthy recreational triathletes lasting up to 2.5 h post-swim. Some individuals appear to be more susceptible to pulmonary impairments than others, although these mechanisms need to be studied further.

Biochemical markers after the Norseman Extreme Triathlon

Prolonged exercise is known to cause changes in common biomarkers. Occasionally, competition athletes need medical assistance and hospitalisation during prolonged exercise events. To aid clinicians treating patients and medical teams in such events we have studied common biomarkers after at The Norseman Xtreme Triathlon (Norseman), an Ironman distance triathlon with an accumulated climb of 5200 m, and an Olympic triathlon for comparison. Blood samples were collected before, immediately after, and the day following the Norseman Xtreme Triatlon (n = 98) and Oslo Olympic Triathlon (n = 15). Increased levels of clinical significance were seen at the finish line of the Norseman in white blood cells count (WBC) (14.2 [13.5–14.9] 109/L, p < 0.001), creatinine kinase (CK) (2450 [1620–3950] U/L, p < 0.001) and NT-proBNP (576 [331–856] ng/L, p < 0.001). The following day there were clinically significant changes in CRP (39 [27–56] mg/L, p < 0.001) and Aspartate Aminotransferase (AST) (142 [99–191] U/L, p < 0.001). In comparison, after the Olympic triathlon distance, there were statistically significant, but less clinically important, changes in WBC (7.8 [6.7–9.6] 109/L, p < 0.001), CK (303 [182–393] U/L, p < 0.001) and NT-proBNP (77 [49–88] ng/L, p < 0.01) immediately after the race, and in CRP (2 [1–3] mg/L, p < 0.001) and AST (31 [26–41] U/L, p < 0.01) the following day. Subclinical changes were also observed in Hemoglobin, Thrombocytes, K+, Ca2+, Mg2+, Creatinine, Alanine Aminotransferase and Thyroxine after the Norseman. In conclusion, there were significant changes in biomarkers used in a clinical setting after the Norseman. Of largest clinical importance were clinically significant increased WBC, CRP, AST, CK and NT-proBNP after the Norseman. This is important to be aware of when athletes engaging in prolonged exercise events receive medical assistance or are hospitalised.

Thermoregulatory, metabolic, and cardiovascular responses during 88 min of full-body ice immersion - A case study

Exposure to extreme cold environments is potentially life-threatening. However, the world record holder of full-body ice immersion has repeatedly demonstrated an extraordinary tolerance to extreme cold. We aimed to explore thermoregulatory, metabolic, and cardiovascular responses during 88 min of full-body ice immersion. We continuously measured gastrointestinal temperature (T_gi ), skin temperature (Tskin), blood pressure, and heart rate (HR). Oxygen consumption (VO₂ ) was measured at rest, and after 45 and 88 min of ice immersion, in order to calculate the metabolic heat production. Tskin dropped significantly (28-34°C to 4-15°C) and VO₂ doubled (5.7-11.3 ml kg^-1  min^-1 ), whereas Tgi (37.6°C), HR (72 bpm), and mean arterial pressure (106 mmHg) remained stable during the first 30 min of cold exposure. During the remaining of the trial, Tskin and VO₂ remained stable, while Tgi gradually declined to 37.0°C and HR and mean arterial blood pressure increased to maximum values of 101 bpm and 115 mmHg, respectively. Metabolic heat production in rest was 169 W and increased to 321 W and 314 W after 45 and 80 min of ice immersion. Eighty-eight minutes of full-body ice immersion resulted in minor changes of Tgi and cardiovascular responses, while Tskin and VO₂ changed markedly. These findings may suggest that our participant can optimize his thermoregulatory, metabolic, and cardiovascular responses to challenge extreme cold exposure.