Annual ECSS-Congress, Bruges 2012
||[OP-PM15] Performance in water
Date & time:
||07.07.2016 / -
|Title of the paper:
Winter swimming - healthy or hazardous?
||Zeman, V., Racek, J., Rajdl, D., Topolcan, O., Novak, J., Trdlickova, P.
||Faculty of Medicine
||Institute of Sports Medicine
WS is swimming in natural water at a temperature (Tw) under 8 °C. WS has been known for many years as a non-competitive event. Recently, however, competitions in WS have been organized. Swimming produces heat. However it also causes vasodilatation in the body surface area and in active muscles and also cold water streams along the body. That’s why the body cooling is greater. Protection against heat losses is possible in two ways: A extension of the isolative ability of the body and B thermogenesis.
A. Vasoconstriction appears in skin and subcutaneous tissue and in inactive muscles. During the long-term cold adaptation higher subcutaneous fat thickness occurs.
B. Thermogenesis is possible due to muscle activity and shivering. The most effective form is the non-shivering thermogenesis induced due to NE.
Cooling a muscle causes its worse function. Both muscle shortening velocity and power decrease and the muscle fatigue arises earlier. The cold activates the sympathetic nervous system. NE increases the BP, FFA mobilization and leukocytosis. The pituitary – adrenal axis is also activated. Thyroid hormones are necessary for the development of the cold adaptation. NE reduces blood flow also in kidneys and GF falls (1).
Hypothermia is divided into mild (Tr 32-35°C), middle (Tr 30–32°C), and severe (below 30°C). Hypothalamus begins to lose its ability to regulate body temperature. It is completely lost when Tr falls below 29°C). In severe hypothermia the hospitalisation is necessary. Humans die when their Tr falls to 24 - 25°C).
Cooling of the heart tissue leads via sinus node to a progressive decline of HR followed by arrhythmias and cardiac arrest (4). The face cooling acts similar changes via the diving reflex. Accidents and serious disorders in WS during race appear mostly independently on the grade of hypothermia. During the last decade a case of stroke and a case of coronary artery disease during competition were recorded in CR.
THE POSITIVE INFLUENCE
WS is an instrument for the prevention of illnesses from cold. Enhanced immunity against respiratory infection diseases developed in subjects, who regularly shower or bath in cold water. The cause lies in a higher level of plasmatic IgA (3). WS results in increased stimulation of immune system. Organism manages then easily common situations rising as a result of a relatively slight and short-term cold exposure (2)
1. Wilmore JH, Costill DL (1999) Physiology of Sport and Exercise. Human Kinetics.
2. Zeman V, (2006). Cold adaptation in man. Prague. Galen.
3. Zeman V, Sramek P, Ulicny B, et al. (1993). Med Sport Boh Slov 2, 66-71.
4. Zindler M, Dudziak R, Bunike S, (1973). Medizin, Band 11, Berlin, VEB Verlag.
Supported by Ministry of Health, CZ 006698
||Sports Medicine and Orthopedics
||winter swimming (WS)