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.

The study was conducted to evaluate the metabolic responses to a 24 h ultra-endurance race in male runners. Paired venous and capillary blood samples from 14 athletes (mean age 43.0 ± 10.8 years, body weight 64.3 ± 7.2 kg, VO_2max 57.8 ± 6.1 ml kg⁻¹ min⁻¹), taken 3 h before the run, after completing the marathon distance (42.195 km), after 12 h, and at the finish of the race, were analyzed for blood morphology, acid–base balance and electrolytes, lipid profile, interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP), and serum enzyme activities. Mean distance covered during the race was 168.5 ± 23.1 km (range 125.2–218.5 km). Prolonged ultra-endurance exercise triggered immune and inflammatory responses, as evidenced by a twofold increase in total leukocyte count with neutrophils and monocytes as main contributors, nearly 30-fold increase in serum IL-6 and over 20-fold rise in hsCRP. A progressive exponential increase in mean creatine kinase activity up to the level 70-fold higher than the respective pre-race value, a several fold rise in serum activities of aspartate aminotransferase and alanine aminotransferase, and a fairly stable serum γ-glutamyl transferase level, were indicative of muscle, but not of liver damage. With duration of exercise, there was a progressive development of hyperventilation-induced hypocapnic alkalosis, and a marked alteration in substrate utilization towards fat oxidation to maintain blood glucose homeostasis. The results of this study may imply that progressive decline in partial CO₂ pressure (hypocapnia) that develops during prolonged exercise may contribute to increased interleukin-6 production.

Purpose To evaluate ongoing metabolic changes during a 48-h competitive run and a 48-h recovery period, with focus on potential health risks exemplified by heart and skeletal muscle damage biomarkers and oxidative stress-related indices. Methods Blood samples were taken before the race, after 12, 24, and 48 h of running, and after 24 and 48 h of recovery from male amateur runners (N = 7, age 35–59 years, VO_2max mean ± SD 57.0 ± 4.0 ml kg⁻¹ min⁻¹, total distance covered 183–320 km). The samples were analyzed for morphology, acid–base and electrolyte balance, iron status, lipid profile, interleukin-6, high-sensitivity C-reactive protein, N-terminal pro-brain-type natriuretic peptide, high-sensitivity cardiac troponin T, non-enzymatic antioxidants, activities of selected enzymes including antioxidant enzymes, and total antioxidant status. Results The sustained ultra-endurance run caused hypocapnic alkalosis with slight hyperkalemia and hypocalcemia, but no hyponatremia. Blood biochemistry showed severe muscle but not liver damage, and an acute inflammatory response. These effects were evidenced by leukocytosis, several fold rises in interleukin-6 and high sensitivity C-reactive protein, extreme elevations in serum levels of muscle enzymes, and marked increases in cardiac biomarker levels. Most of the changes dissolved during the 48 h post-race recovery. Neither the iron pool, nor erythropoiesis, nor pro-oxidant/antioxidant balance were substantially affected. Conclusions The changes consequent on the ultra-endurance run do not pose a serious health risk in men who begin their endeavor with ultra-endurance running in mid-life. There is some circumstantial evidence that hyperventilatory hypocapnia may modulate inflammatory response by stimulating the release of interleukin-6 from working skeletal muscles.

The beneficial adaptation of skeletal muscle function to strenuous exercise is partially attributable to the improvement of vitamin D status. The present study aimed to evaluate the effects of a 3-week vitamin D supplementation on serum 25(OH)D levels and skeletal muscle biomarkers (i.e. troponin, myoglobin, creatine kinase and lactic dehydrogenase) of endurance runners. A double-blind placebo-controlled study design was used and vitamin D supplementation was compared to a non-treatment control group. Twenty-four runners, competitors of the ultra-marathons held during the National Running Championships, were randomly assigned into two groups supplemented with the dose of 2000 IU vitamin D or placebo for three weeks. All subjects participated in three exercise protocols: (a) incremental exercise test (to determine the maximum oxygen uptake and the intensity of eccentric exercise), (b) eccentric exercise before and (c) after two dietary protocols. Venous blood samples were drawn at rest, immediately after the exercise and after 1 h and 24 h of recovery in order to estimate serum 25(OH)D levels, skeletal muscle biomarkers, proinflammatory cytokines and tumor necrosis factor-alpha (TNF-α) levels. A two-way ANOVA was used to test main effects and their interactions and Pearson correlation coefficients were analyzed to determine the effects of inter-variable relationships. Significant differences between pre- and post-intervention in baseline 25(OH)D levels were observed (34.9 ± 4.7 versus 40.3 ± 4.9 ng/ml, p = 0.02) in supplemented group. A higher post intervention 25(OH)D level was observed after vitamin D diet compared to placebo (40.3 ± 4.9 versus 31.8 ± 4.2 ng/mL, respectively; p < 0.05). The vitamin D supplementation decreased post-exercise (TN max) and 1 h post-exercise troponin (p = 0.004, p = 0.03, respectively), 1 h post-exercise myoglobin concentration (p = 0.01) and TNF-α levels(p < 0.03). 24 h post exercise creatine kinase activity was significantly lower in supplemented group compared to placebo (p < 0.05). A negative correlation was observed between post exercise 25(OH)D levels and myoglobin levels (r = − 0.57; p = 0.05), and 25(OH)D levels and TNFα (r = − 0.58; p = 0.05) in vitamin D supplemented group. Three weeks of vitamin D supplementation had a positive effect on serum 25(OH)D levels in endurance trained runners and it caused a marked decrease in post-exercise biomarkers levels. We concluded that vitamin D supplementation might play an important role in prevention of skeletal muscle injuries following exercise with eccentric muscle contraction in athletes.

The aim of this study was to compare the motivations of successful marathon finishers (n=1,243) and inexperienced runners (control group, n=296). A total of 1,537 runners with 380 women (24.7%) and 1,157 men (75.3%) completed the Motivations of Marathoners Scales (MOMS) questionnaire, and the relationships between general motivation categories and selected demographic (e.g. gender, age, and education) and training characteristics were analyzed. Successful marathon finishers did not differ significantly in motivations from the control group (p > 0.05). Trivial to small correlations with age, educational level, and training characteristics were observed. Women marathon finishers exceeded men on the motivational scales for weight concern, affiliation, psychological coping, life meaning, and self-esteem and they scored lower on competitive motivation (p < 0.05). These findings confirmed that age and gender differentiate motivations in both successful marathon finishers and controls. There was also a significant relationship of some motivational aspects with level of education, experience and training frequency.

Background: In ultra-marathon running the proper motivation of the athlete is one of the milestones, not only during the races, but also during the practice sessions, which are long and very exhausting. Purpose: The aim of this study was to examine the relationship of sport experience (expressed as number of finishes in ultra-marathons) with motivation characteristics of ultra-marathon runners. Subjects and methods: The Motivation of Marathoners Scale examined the motivation of ultra-marathon runners compared to endurance runners of shorter distances (control group). Participants were 1,539 Polish runners, 382 women (24.7%) and 1,157 men (75.3%). Ultra-marathoners (N=425; 26.7%) finished at least one ultra-marathon, whereas the control group consisted of runners of shorter distances (N=1,114, 72.3%). Results: Ultra-marathoners had higher scores in affiliation (3.55±1.60 vs 3.34±1.62, P<0.05), life meaning (4.20±1.40 vs 4.03±1.44, P<0.05) and lower in the areas of weight concern (4.33±1.68 vs 4.64±1.65, P<0.01), personal goal achievement (5.09±1.25 vs 4.64±1.65, P<0.001) and self-esteem (4.44±1.36 vs 4.68±1.38, P<0.01), than runners in the control group. The number of completed ultra-marathons was negatively related to the personal goal achievement, competition and recognition scale. The level of training experience was negatively correlated with the personal goal achievement scale in all participants, and with the self-esteem scale in the control group. In summary, ultra-marathoners had different motivations compared to runners of shorter race distance. Conclusions: These findings should be considered by sport psychologists and other professionals to develop performance-tailored interventions for ultra-marathoners.