Healthy_back (healthy_back) wrote,

Тепло и холод

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Cold and superficial heat are probably the most widely used therapeutic modalities in athletic training. Despite the fact that these modalities have been used by certified athletic trainers for many years, their physiological effects and purported clinical benefits have not been fully established. Thus, the analgesic and antispasmodic effects of cold and superficial heat are emphasized.

Cooling and rewarming skin and deeper tissues

1. Skin cools more rapidly and to a greater extent than deeper tissues
2. Rate of cooling levels off, but continues to drop following ice removal at rest
3. Similar pattern of tissue rewarming occurs with removal of cold—more rapidly if followed by physical activity
4. Research suggests that intra-articular temperature decrease is greater than in surrounding muscles

Blood flow: physiological response to cooling

1. Lowers metabolic activity and oxygen demand of cells
2. Vasoconstriction: superficial and deep tissues through reflex mechanisms
3. Decreased metabolic activity: decreased blood flow in deep tissues

# Suggested that cold initially stimulates cold and pain receptors

1. Intense cold
2. Aching pain
3. Pins and needles
4. Numbness

# Sensation of cold diminishes as cooling of nerve fibers slows conduction of neural impulses

1. No transmission from periphery to sensory cortex
2. Analgesia = pain relief

# Muscle spasm and function

1. Cold application appears to decrease spasm as muscle spindles become less sensitive: muscle relaxes
2. Force production of muscle decreased by cooling: must rewarm muscle tissue before exerting maximal efforts

Indications for therapeutic cold/acute inflammation

1. Relief of pain and muscle spasm
2. Acute inflammation: combine compression, elevation, protection of injury early, and repeat for maximum effect
3. Hypoxic cell death
4. Secondary cell death

Cold therapy in the treatment of persistent pain

1. Can be effective in managing myofascial pain syndrome
2. Short, intense exposure to sensitive points may decrease pain by stimulating nociceptive pathway
3. Prolonged exposure decreases sensitivity of free nerve endings and slows conduction of afferent fibers
4. Breaks local pain–spasm cycles

Does cold application improve treatment outcomes?

1. Additional studies are needed
2. Can conclude that therapy is likely to reduce pain and decrease secondary tissue injury
3. Some evidence leads to conclusion that cold therapy may speed recovery following ankle and knee surgery

Superficial heat

# Temperature increases and physiological responses

1. Calming, analgesic effects: not well understood as mechanism of action has not been established
2. Breaks the pain–spasm cycle: a possible decrease in muscle spindle activity is speculative

3. Increased metabolic activity, circulation, inflammation, and tissue elasticity
4. Decreased viscosity
5. Increased sweating
6. Superficial heating does little to alter deep tissues

# Indications for superficial heating

1. Traditionally used to reduce pain and muscle spasm prior to therapeutic exercise
2. Certain applications allow passive or active range of motion (PROM, AROM) simultaneously
3. Can treat restrictions in superficial joints

Does superficial heat improve treatment outcomes?

1. Related literature is limited
2. Superficial heat does have a clinically useful analgesic effect based on what literature is available

# Heat and cold: contrast therapy

1. Physiological effects
1. Proposed pumping action created by cycles of vasodilation and vasoconstriction
2. Tissue temperatures not affected
2. Indications
1. Subacute conditions where swelling, pain, and spasm limit ROM
2. Observe contraindicated cautions for superficial heat applications

# Heat, cold, and contrast therapy: deciding what to apply

1. Contraindications
1. Consider precautions for heat and cold to determine potential benefits versus risks to each individual
2. Superficial heat is generally contraindicated following acute injury
3. Cold continues to be treatment of choice in the management of acute injury

# Superficial heat and local cooling affect blood flow in superficial tissues. Cold can also decrease blood flow in deeper tissues by lowering metabolic activity. Superficial cold and heat also affect the nervous system, although through different mechanisms, resulting in decreased pain and muscle spasm.

Cold application is indicated in the treatment of acute injury to manage the symptoms of inflammation.

Superficial heat is indicated for pain relief and reduction of muscle spasm, as well as in heating very superficial tissues before stretching and manual therapy.
Although therapeutic heat and cold measures are widely used in rheumatic diseases, their application in joint inflammations is still broadly empirical.

Animal experiments concerning the effects of systemic hyperthermia and of local heat and cold applications upon experimentally induced inflammations
show that some inflammations are significantly depressed, i.e. they are effected by a useful therapeutic influence, but that cold and heat can also act as enhancing inflammatory stimulus. Under certain conditions, whole-body hyperthermia has immuno-suppressive effects. Although the exact points of intervention of heat and cold investigations, acute exsudative inflammations seem to be better influenced by cold; on the contrary, chronic torpid and proliferous inflammations are better influenced by heat. Prostaglandin mediated inflammations can be aggravated by cold, because it stimulates the prostaglandin synthesis; acute exsudative inflammatory processes are most often aggravated by heat. These results show that both therapeutic agents should be applied within a well-defined range and with care.
Heat Therapy: Heat increases blood flow and makes connective tissue more flexible. It temporarily decreases joint stiffness, pain, and muscle spasms. Heat also helps reduce inflammation and the buildup of fluid in tissues (edema). Heat therapy is used to treat inflammation (including various forms of arthritis), muscle spasm, and injuries such as sprains and strains.

Cold Therapy (Cryotherapy): Applying cold may help numb tissues and relieve muscle spasms, acute low back pain, and acute inflammation. Cold may be applied using an ice bag, a cold pack, or fluids (such as ethyl chloride) that cool by evaporation. The therapist limits the time and amount of cold exposure to avoid damaging tissues and reducing body temperature (causing hypothermia). Cold is not applied to tissues with a reduced blood supply (for example, when the arteries are narrowed by peripheral arterial disease).

The spread of cold on the skin depends on the thickness of the epidermis, underlying fat and muscle, water content of the tissue, and rate of blood flow. Care must be taken to avoid tissue damage and hypothermia. Cold should not be applied over poorly perfused areas.
Heat provides temporary relief in subacute and chronic traumatic and inflammatory conditions (eg, sprains, strains, fibrositis, tenosynovitis, muscle spasm, myositis, painful back, whiplash injuries, various forms of arthritis, arthralgia, neuralgia). Heat increases blood flow and the extensibility of connective tissue; decreases joint stiffness, pain, and muscle spasm; and helps resolve inflammation, edema, and exudates. Heat application may be superficial or deep. The intensity and duration of the physiologic effects are determined mainly by tissue temperature, the rate of temperature elevation, and the area treated.

The choice between heat and cold therapies is often empiric. When heat does not work, cold is applied. However, for acute pain, cryotherapy seems to be better than heat therapy. Cold application may help relieve muscle spasm, myofascial or traumatic pain, acute low back pain, and acute inflammation and may help induce some local anesthesia.
Ice. Recent studies show that heat doesn't really seem to reduce inflamation much at all, even if it can help with muscle aches.
Excerpt: "There are identifiable and measurable physiologic effects produced by heat and cold that are therapeutically desirable. Heat increases blood flow and cold decreases it. Heat induces an inflammatory response that may be beneficial at some stages of a disease process, whereas cold applications decrease inflammation. Heat increases the production of edema and cold decreases edema formation. It is well known that heat increases the amount of hemorrhage, especially after trauma, whereas cold application decreases it. Of interest is that both heat and cold have been demonstrated to reduce muscle spasm and decrease pain.
# Heat, Cold, or Both? by Carol F. Simpson
Tissue perfusion may be impaired by arterial occlusion or vasoconstriction, hypotension, hypothermia, and peripheral venous congestion. Reduced wound oxygen tension can delay wound healing by slowing the production of collagen. Collagen fibril cross-linking begins to fail as tissue oxygen pressure falls below 40 mm Hg because oxygen is required for the hydroxylation of proline and lysine to synthesize mature collagen. Wound hypoxia also predisposes to bacterial infection because the leukocyte's oxidative phosphorylation bactericidal activities are severely impeded without normal tissue oxygen levels. These factors should be corrected as much as possible.

Normal body temperature in humans is 37°C. Hypothermia can be divided in three stages of severity.

In stage 1, body temperature drops by 1-2°C below normal temperature (35-36°C). Mild to strong shivering occurs.[1][2] The victim is unable to perform complex tasks with the hands; the hands become numb. Blood vessels in the outer extremities constrict, lessening heat loss to the outside air. Breathing becomes quick and shallow. Goose bumps form, raising body hair on end in an attempt to create an insulating layer of air around the body (which is of limited use in humans due to lack of sufficient hair, but useful in other species). Often, a person will experience a warm sensation, as if they have recovered, but they are in fact heading into Stage 2. Another test to see if the person is entering stage 2 is if they are unable to touch their thumb with their little finger; this is the first stage of muscles not working.

In stage 2, body temperature drops by 2-4°C. Shivering becomes more violent. Muscle mis-coordination becomes apparent.[1][2][3] Movements are slow and labored, accompanied by a stumbling pace and mild confusion, although the victim may appear alert. Surface blood vessels contract further as the body focuses its remaining resources on keeping the vital organs warm. The victim becomes pale. Lips, ears, fingers and toes may become blue.

In stage 3, body temperature drops below approximately 32 °C (89.6 °F). Shivering usually stops.[1][2] Difficulty speaking, sluggish thinking, and amnesia start to appear; inability to use hands and stumbling is also usually present. Cellular metabolic processes shut down. Below 30 °C (86.0 °F), the exposed skin becomes blue and puffy, muscle coordination becomes very poor, walking becomes almost impossible, and the victim exhibits incoherent/irrational behavior including terminal burrowing or even a stupor. Pulse and respiration rates decrease significantly but fast heart rates (ventricular tachycardia, atrial fibrillation) can occur. Major organs fail. Clinical death occurs. Because of decreased cellular activity in stage 3 hypothermia, the body will actually take longer to undergo brain death.
Since cold water will carry heat away from the body 25 times faster than air of the same temperature, the average body cools rapidly, and within 20 to 30 minutes, depending on water temperature, body core temperature drops to below 35 degrees C (95 degrees F.) An individual's response to cold water will vary from the average depending on a number of factors including clothing, amount of body fat, activity, etc. but the steady decline in core temperature will continue until the person is removed from the water.
Cold Water Survival
Cold water robs the body's heat 32 times faster than cold air. Physical exercise such as swimming causes the body to lose heat at a much faster rate than remaining still in the water. Blood is pumped to the extremities and quickly cooled. The major body heat loss areas are the head, neck, armpits, chest and groin.

In the diving reflex, blood is diverted away from the arms and legs to circulate (at the rate of only 6-8 beats per minute, in some cases) between the heart, brain and lungs.

Expected Survival Time in Cold Water
Cold water removes heat from the body 25 times faster than cold air. About 50% of that heat loss occurs through the head. Physical activity such as swimming, or other struggling in the water increases heat loss.

Hypothermia (decreased body temperature) develops more slowly than the immediate effects of cold shock. Muscle rigidity and loss of manual dexterity, physical helplessness, occurs at about 93 degrees F. Mental capacity also deteriorates at this point.

Survival tables suggest that a victim may survive for a relatively long time in cold water (40-50 degrees F, 1-3 hrs). These tables are only valid if the victim is wearing a life jacket. Without the flotation of the life jacket, the victim is forced to swim, which drastically accelerates heat loss, onset of paralysis, and drowning.

Heat Balance: The Basic Physics ^

In order to understand the cause of hypothermia, it is important to understand the basic physics of how a human maintains heat balance.

Heat flows down a thermal gradient from high to low temperatures. Thus, in the cold, a thermal gradient is established, down which heat "flows" from the warmer deeper tissues to the cooler tissues near the surface of the body. Heat then escapes from the body to the environment. In normal circumstances in air, the body can exchange heat with the environment via four physical processes: radiation (R), convection (C), conduction (K), and evaporation (E).

R (Radiation). All objects possessing heat, including the body, emit thermal radiation from their surfaces.

C (Convection). This is the process by which heat is exchanged with the environment by the movement of air or water molecules adjacent to the skin, as they move away they are replaced by colder molecules.

K (Conduction). This term is used to describe heat exchange between the skin and surrounding surfaces with which it is in direct contact.

E (Evaporation). Evaporation is the process by which energy transforms liquid to a gas. The heat required to drive this process is removed from the surface of the object on which evaporation is occurring, and it cools.

For body temperature to remain stable in a cool environment, the heat produced by the body at rest or through exercise or shivering (M), must match that lost by R,C,K and E.

Several factors influence the amount of heat exchanged by R,C,K, and E. The most common are:
- the surface area involved in heat exchange;
- the temperature gradient between the body and the environment;
- and the relative movement of the fluid (air or water) in which the body is placed.

This explains why someone will cool faster if: they are in colder water (gradient); they are partially immersed compared to completely immersed (surface area); they are in fast flowing as opposed to still water (movement of the fluid); they move about compared to staying still (relative movement of the fluid).

In water, heat is conducted to the molecules of water in contact with the skin ("boundary layer"), these molecules are warmed and rise (Convection), and are replaced by cooler ones. Thus, in water only two of the four primary pathways for heat exchange are available, and heat loss is principally by convective and conductive heat exchange. Despite this, a naked individual in cold water will cool approximately four times faster than in air at the same temperature. This is because the thermal conductivity of water is 25 times that of air, and its volume-specific heat capacity is approximately 3500 times that of air. Therefore, water has a much greater capacity to extract heat (see Footnote). Furthermore, when in water, unlike air, the surface area available for heat exchange with the environment comes close to 100%. This is the reason why cold water is so dangerous. The corollary to this is that hot water is a very good medium to rewarm hypothermic victims.

If the immersed person has survived the initial two stages of immersion, i.e. cold shock and swimming failure, then the next hurdle to face is hypothermia. It is now known that this per se may not be the cause of death. This was noted by Golden (1996) (Reference 19). As previously stated in Chapter 1, the predicted 50% survival times for fully clothed men in water wearing lifejackets are 1 hour at 5°C, 2 hours at 10°C, and 6 hours at 15°C. Yet these figures are difficult to validate in the laboratory where the body temperature only falls about two or three degrees in the equivalent time. There must be another cause of death. Golden explained that a conscious survivor in a seaway will make the physical effort to keep his/her back against the waves, but when physically impaired through muscle cooling, semi-conscious and with a loss of determined will to survive, both of which occur after a body core temperature drop between 2-3°C, then the survivor turns into the waves and drowns. He also emphasized the point that death will occur much quicker from drowning if a lifejacket is not worn (Figure 5, Reference 15).

Footnote: The volume-specific heat capacity is obtained by multiplying the specific heat of a substance by its density. It represents the amount of heat required to raise the temperature of a given volume of water by 1ºK. At 37ºC the volume-specific heat capacity of water is 3431 times that of air.

Swimming has a massive impact on the rate of body cooling and can increase the rate between 30-40% (Reference 35).
В стандартных и крупных плавательных бассейнах с длиной дорожки 25-50 м, где активно занимаются люди, умеющие плавать, достаточна температура воды около 22С, а в учебных плавательных бассейнах с длиной дорожки 8-16 м температура воды должна быть 23-26С. При использовании плавания в медицинских целях (для разгрузки позвоночника у не совсем здоpoвых людей) температура воды должна превышать 26С, а лучше всего равняться 28С ( при температуре ниже 25С могут появиться судороги).
Самым неприятным последствием посещения бассейна может стать грибок на ногах. Проблемы возникают, если человек не соблюдает правила гигиены: пользуется чужим полотенцем, мочалкой или не носит шлепанцы в бассейне. Особенно грибок любит влажные деревянные поверхности, поэтому лучше избегать прикосновений с бортиками, скамейками.
Постановление Главного государственного санитарного врача РФ
от 28 мая 2003 г. N 104
"О введении в действие СанПиН"

Санитарно-гигиенические требования к бассейнам аквапарков
Бассейны для плавания 26-29оС
Ввести в действие санитарно-эпидемиологические правила и нормативы "Плавательные бассейны. Гигиенические требования к устройству, эксплуатации и качеству воды. Контроль качества. СанПиН", утвержденные Главным государственным санитарным врачом Российской Федерации 29 января 2003 года, с 1 мая 2003 г.

5.3.2. Лабораторный контроль за качеством воды в ванне бассейна включает исследования по определению следующих показателей:

в) основные микробиологические показатели (общие колиформные бактерии, термотолерантные колиформные бактерии, колифаги и золотистый стафилококк) 2 раза в месяц;
г) паразитологические - 1 раз в квартал;
д) содержание хлороформа (при хлорировании) или формальдегида (при озонировании) - 1 раз в месяц.

Таблица N 1. Виды бассейнов и санитарно-гигиенические требования к их устройству

Температура воды, град. С Спортивные 24-28
По данным Москомспорта, ежедневно столичные бассейны посещают около 28 тыс. человек. Всем им должны быть обеспечены условия, описанные Санитарными правилами и нормами (СанПиН) "Плавательные бассейны. Гигиенические требования к устройству, эксплуатации и качеству воды. Контроль качества". Этот документ, в частности, утверждает, что качество воды в искусственном бассейне должно быть не хуже, чем у питьевой. В Комитете физкультуры и спорта Москвы уверяют, что пробы в любом городском бассейне берут по пять-шесть раз в день. За этим обязана следить администрация, образцы воды берет лаборант. Кроме того, специалисты из Роспотребнадзора (бывший Госсанэпиднадзор) могут приехать в любой день, проверить показатели и, если они неудовлетворительны, закрыть бассейн до устранения недостатков.

Как заявила ИП заместитель генерального директора Агентства по защите прав потребителей Ирина Соколова, вызвать в бассейн инспекторов может и любой человек, пришедший туда поплавать.

Теоретически никто не запрещает гражданам обращаться в Роспотребнадзор с просьбой проверить воду в любимом бассейне. Другой вопрос - приедет ли инспектор по вашему сигналу.

Впрочем, если вы пришли поплавать, а вам показалось, что вода в бассейне холодна и не слишком чиста, ждать прихода инспекторов Роспотребнадзора не нужно.

"В каждом бассейне должна быть таблица, где указана температура воды и воздуха, - рассказал ИП заместитель генерального директора Олимпийского центра водного спорта Вадим Лоскутов. - Обычно бассейны не афишируют данные о содержании микроорганизмов, но если уж клиент желает, то мы можем ознакомить его и с этой информацией". "Статья 10 закона "О защите прав потребителей" гласит: "исполнитель обязан своевременно предоставлять потребителю необходимую и достоверную информацию об услугах". Плавание в бассейне - это услуга, поэтому на основании этой статьи любители купания могут требовать информацию о том, как в бассейне обстоит ситуация с микроорганизмами", - соглашается с руководителем бассейна защитник прав потребителей Ирина Соколова.

Чистота воды - одно из важнейших потребительских свойств бассейна, и обеспечить ее в общедоступном заведении совсем непросто. Экспериментально установлено, что человек за полчаса пребывания в воде оставляет в ней до 30 тыс. микроорганизмов. Водообмен в бассейне происходит за счет рециркуляции: вода не сливается сразу в канализацию, а проходит через систему фильтров, после чего в основном вновь попадает в ванну бассейна с добавлением не менее 10% свежей. Полная же смена воды должна происходить не более чем за 12 часов работы бассейна. Чтобы убить микроорганизмы, вода специально обрабатывается. Обеззараживание может быть реагентным (с использованием хлора, перекиси водорода, солей меди и серебра) и безреагентным (озонирование, электролитическое окисление, ультрафиолетовое облучение). Безреагентными методами пользуются только за границей. Практически во всех столичных плавательных учреждениях в качестве способа очистки воды применяется хлорирование.

Причина кроется в силе бактерицидного действия хлора, к тому же никакой другой метод не способен поддерживать воду в относительной чистоте так долго. "Знайте, что те бассейны, которые указывают в качестве очистки не хлорирование, а, скажем, озонирование, лукавят", - говорит директор бассейна Дворца водного спорта "Фили" Николай Бредов.
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