link on wikipedia http://en.wikipedia.org/wiki/Cold_shock_response
The most common stress that living organisms constantly confront in nature is likely to result from temperature changes.
Cold-shock research is a hot topic and its further advancement will not only yield new exciting discoveries with respect to biological function, but will also aid the improvement of human health and to the energy conservation of households.
Cold-water stepping, dew walking, dry brushing and lymph drainage are all useful in stimulating the skin.
Take a cold bath or shower daily for a few seconds to improve the circulation and immune system. Regular swimming in cold water is excellent.
Numerous studies show that small amounts of harmful or stressful agents (e.g. heat stress, cold stress, hypergravity) can be beneficial for the health of laboratory animals, the phenomenon that became known as hormesis.
Daily moderate cold hydrotherapy is known to reduce pain and does not appear to have noticeable adverse effects on normal test subjects, although some studies have shown that it can cause transient arrhythmias in patients with heart problems and can also inhibit humoral immunity.
The possible mechanism of the non-specific stimulation of cellular immunity by repeated cold stress appears to involve transient activation of the sympathetic nervous system, hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes.
Brief cold-water stress repeated daily over many months could enhance anti-tumor immunity and improve cancer survival rate in a mouse (non-lymphoid) tumor model. []
Brief whole-body exposure to cold water has been shown to increase both activity and numbers of peripheral natural killer (NK) cells and CD8+ T lymphocytes in mice. This effect could be explained by transient activation of the sympathetic nervous system (SNS), the hypothalamic-pituitary-adrenal (HPA) axis as well as the hypothalamic-pituitary-thyroid (HPT) axis [19,20] resulting in a brief action of norepinephrine, adrenocorticotropic hormone (ACTH), beta-endorphin, and thyroid hormones (triiodothyronine (T3) and thyroxine (T4)) on cytotoxic T lymphocytes (CTLs) and NK cells. Interestingly, brief cold swim stress repeated for 8 days was also reported to increase survival of mice infected with intracellular parasite Toxoplasma gondii, the situation that is consistent with enhancement of cellular immunity. Based on this evidence and given the fact that NK cells and CTLs are major components of an anti-tumor immune response, it seems logical to propose the following hypothesis.
Daily moderate cold water stress does not appear to have noticeable adverse effects on normal test subjects either short-term or long-term and, interestingly, in a near-life-time experiment on healthy rats, where the animals had to stand in 23°C water 4 hours per day 5 days per week, the repeated cold stress extended the lifespan by statistically 5% and somewhat reduced spontaneous incidence of tumors, especially sarcomas. Based on the evidence presented earlier, more frequent exposure to cold of shorter duration, for example 5-minute cold swim stress twice per day (>7 hours apart), could have a more significant immunostimulatory effect and a less pronounced effect on metabolism compared to the above experiment. Cold water stress is also known to have an analgesic effect, which is often relevant in cancer.
Exposure to acute cold for extended periods of time can cause a significant drop of core body temperature (hypothermia) which can be associated with such adverse effects on health as ataxia, hypovolemia, atrial dysrhythmias, cold diuresis, and mental confusion. Immersion in moderately cold water in the range of 16–23°C does not appear to cause hypothermia (core temperature of 35°C or lower) in healthy human subjects, even when it lasts for several hours. During this procedure, core body temperature stays virtually unchanged during the first hour due to unusual efficiency of the human thermoregulatory system. It should be noted that the elderly or people with certain metabolic disorders may develop hypothermia under these conditions, and thus body temperature should be monitored in these groups of people if they use cold hydrotherapy.
Winter swimming (in other words, sudden immersion in ice-cold water) may pose serious risks to health and it is possible that exposure to cold can be safer if it is brief and does not involve psychological distress, inhalation of cold air, and hypothermia.
Transient changes in environmental temperature produce a short-term, but significant effect on the immune system reactions in laboratory mice.
Exposure to cold water activated cellular immunity, while warm water activated humoral immune system.
Whole-body cryotherapy (WBC; -110 degrees C) and winter swimming (WS) in ice-cold water are severe ambient cold exposures, which are voluntarily practiced by humans in minimal clothing. The purpose was to examine thermal sensation and thermal comfort associated with WBC and WS. Twenty women similar in body mass index, age, physical activity, and use of hormonal contraception were pairwise randomized either to the WBC group or the WS group. The duration of each WBC exposure was 2 min, which was repeated three times per week for 3 months (13 weeks). Similar exposure frequency was used for the WS group, but each exposure lasted 20 s in outdoor conditions. Thermal sensation and comfort were asked with standard scales. After WBC, 65% of the thermal sensation votes were 'neutral' or 'slightly cool.' After WS, 81% of the thermal sensation votes were 'warm,' 'neutral,' or 'slightly cool.' Majority of comfort votes immediately after exposures in WBC group (98%) and in the WS group (93%) were 'comfortable' or 'slightly uncomfortable.' Thermal sensation and comfort became habituated in both groups at an early stage of trials, but the changes were less conclusive in WS group due to variable conditions outdoors. In the WBC group, cold sensation was less intense already after the second exposure. In conclusion, repeated exposures to WBC and WS in healthy women were mostly well tolerated and comfortable. The results indicate that during repeated severe whole-body cold stress of short duration, thermal sensation and comfort become habituated during the first exposures. []
Cryogenic chamber therapy (from wikipedia)
Cryogenic chamber therapy is a treatment whereby the patient is placed in a cryogenic chamber for a short duration (i.e. no more than three minutes, which is comparable to ice swimming), and if used properly, will not destroy tissue. Whole body cryotherapy initially originated in Japan in 1880. However, it was a group of Polish scientists who took the idea and made whole body cryotherapy the physical therapy it is today. The Olympic rehabilitation centre in Spala, Poland opened in May 2000 and has been used as a training and injury rehabilitation centre for many sporting bodies.
The chamber is cooled, typically with liquid nitrogen, to a temperature of −110 °C (−166.0 °F). The patient is protected from acute frostbite with socks, gloves and mouth and ear protection, but in addition to that, wears nothing but a bathing suit. The patient spends a few minutes in the chamber. During treatment the average skin temperature drops to 12 °C (54 °F), while the coldest skin temperature can be 5 °C (41 °F). The core body temperature remains unchanged during the treatment, however it may drop slightly afterwards. Therapy triggers the release of endorphines which induce analgesia (immediate pain relief).
Patients report that the experience is invigorating and improves a variety of conditions such as psychological stress, insomnia, rheumatism, muscle and joint pain, fibromyalgia, itching, and psoriasis. The immediate effect of skin cooling and analgesia lasts for 5 minutes, but the release of endorphines can have a lasting effect, where the pains and signs of inflammation as found in blood tests remain suppressed for weeks. The effects of extreme cold and endorphine release are scientifically studied. Curiously, some patients compare the feeling to sauna at 110 °C (230 °F).