Thermal stress and oxidant–antioxidant balance in experienced and novice winter swimmers

The Influence of Winter Swimming on Oxidative Stress Indicators in the Blood of Healthy Males

Baths in cold water are a popular physical activity performed to improve health. This study aimed to determine whether repeated cold-water exposure leads to the up-regulation of antioxidant defenses and whether or not this leads to a reduction in basal and/or acute pulses of oxidative distress in humans. The study group consisted of 28 healthy male members of the WS club (average age 39.3 ± 6.1 years). The study sessions occurred at the beginning and the end of the WS season. During the WS season, the participants took 3-min cold-water baths in a cold lake once a week. Blood samples were collected three times during each session: before the bath, 30 min after the bath, and 24 h after the bath. The activity of selected antioxidant enzymes, including superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx), as well as the concentration of lipid peroxidation (LPO) products, including thiobarbituric acid-reactive substances (TBARS) and conjugated dienes (CD), were determined in erythrocytes. The concentration of TBARS, CD, retinol, and α-tocopherol were determined in the blood plasma, whereas the level of other LPO products, including 4-hydroxynonenal and 8-iso-prostaglandin F2α, were determined in the blood serum. The repeated cold exposure up-regulated most antioxidant defenses, and this led to an attenuation of most indicators of oxidative stress at the baseline and acute pulses in response to cold exposure. In conclusion, due to regular cold exposure, the antioxidant barrier of winter swimmers was stimulated. Thus, short cold-bath sessions seem to be an effective intervention, inducing promoting positive adaptive changes such as the increased antioxidant capacity of the organism.

Health effects of voluntary exposure to cold water - a continuing subject of debate

This review is based on a multiple database survey on published literature to determine the effects on health following voluntary exposure to cold-water immersion (CWI) in humans. After a filtering process 104 studies were regarded relevant. Many studies demonstrated significant effects of CWI on various physiological and biochemical parameters. Although some studies were based on established winter swimmers, many were performed on subjects with no previous winter swimming experience or in subjects not involving cold-water swimming, for example, CWI as a post-exercise treatment. Clear conclusions from most studies were hampered by the fact that they were carried out in small groups, often of one gender and with differences in exposure temperature and salt composition of the water. CWI seems to reduce and/or transform body adipose tissue, as well as reduce insulin resistance and improve insulin sensitivity. This may have a protective effect against cardiovascular, obesity and other metabolic diseases and could have prophylactic health effects. Whether winter swimmers as a group are naturally healthier is unclear. Some of the studies indicate that voluntary exposure to cold water has some beneficial health effects. However, without further conclusive studies, the topic will continue to be a subject of debate.

Assessment of blood morphology, electrolyte level as well as kidney and liver function before and after leaving the water in a winter swimmers during the entire winter swimming season - a case study

Study aim: The aim of the study was to assess blood morphology, electrolyte level as well as indices of kidney function and the activity of selected liver enzymes determining liver function before and after exiting the water in a winter swimmer (“Walrus”) from the “Kaloryfer” (“Radiator”) Krakow Winter Swimming Club during the whole winter bathing season. Materials and methods: The subject of research was a winter swimmer from the “Radiator” Krakow Winter Swimming Club  a 53-year-old male. Blood was collected from the subject: at the beginning of the winter swimming season, during (five times) and at the end of the season (each time before and after getting out of the water); time maintaining in water: 10 minutes. Results: Analysing the average values of the indices before and after exiting the water, statistically significant increases were noted in AST [U/L] by 6.4% and LDH [U/L] by 2.45%, as well as a decrease in Na+ [mmol/l] by 1.14%, Clˉ [mmol/l] by 1.78% and urea [mmol/l] by 3.64%. Conclusions: Regular baths taken by the winter swimmers in cold water did not affect blood morphology indices and did not cause pathological changes in kidney profile. Furthermore, slight fluctuations regarding the concentration of electrolytes in the blood serum and changes in the hepatic profile additionally “externalised” health problems, which appeared prior to winter swimming.

Ameliorative effects of melatonin administration and photoperiods on diurnal fluctuations in cloacal temperature of Marshall broiler chickens during the hot dry season

Experiments were performed with the aim of determining the effect of melatonin administration on diurnal fluctuations in cloacal temperature (CT) of Marshall broiler chickens during the hot dry season. Birds in group I (12L:12D cycle) were raised under natural photoperiod of 12-h light and 12-h darkness, without melatonin supplementation, while those in group II (LL) were kept under 24-h continuous lighting, without melatonin administration. Broiler chickens in group III (LL + melatonin) were raised under 24-h continuous lighting, with melatonin supplementation at 0.5 mg/kg per os. The cloacal temperatures of 15 labeled broiler chickens from each group were measured at 6:00, 13:00, and 19:00 h, 7 days apart, from days 14-42. Temperature-humidity index was highest at day 14 of the study, with the value of 36.72 ± 0.82 °C but lowest at day 28 with the value of 30.91 ± 0.80 °C (P < 0.0001). The overall mean hourly cloacal temperature value of 41.51 ± 0.03 °C obtained in the 12L:12D cycle birds was significantly higher (P < 0.001) than the value of 41.16 ± 0.03 °C recorded in the melatonin-treated group but lower than that of 41.65 ± 0.03 °C obtained in the LL birds. Mortality due to hyperthermia commenced at day 28 in both 12L:12D cycle and LL broiler chickens but was delayed till day 42 in LL + MEL broiler chickens. In conclusion, melatonin administration alleviated the deleterious effects of heat stress on broiler chickens by maintaining their cloacal temperature at relatively low values.