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King Saud University Collage of Applied Medical Sciences Rehabilitation Department Hydrotherapy course For level six By Dr. Afaf Ahmed Shaheen 2007-1428 Contents Page Introduction - Structure of the skin Circulatory system of the skin Types of sensation Types of sensory receptors Types of nerve fibers Definition of hydrotherapy Advantages of hydrotherapy Therapeutic properties of water - Physical properties - Chemical properties Physiological effects of hydrotherapy - General physiological effects Physiological effects of heat Physiological effects of cold Indications, Contraindications hydrotherapy Immersion Bathes - Hot bathes Cold bathes Neutral bathes Contrast bathes Whirlpool bathes Hubbard tank Paraffin bath Douches - Jet douche Scotch douche Under water douche Packs - Hot packs Cold packs Chemical packs Cryotherapy Hydrogymnastics - Examples of under water exercises and precautions of Objectives Upon completion of this course the students should be able to: 1. 2. 3. 4. Know what the meaning of hydrotherapy is. Discuss the physical properties of water. Identify the physiological effects of hydrotherapy. Examine how the physical properties and physiological effects of hydrotherapy can be used for muscloskeletal, support and resistance, cardiovascular and respiratory training and psychological benefits. 5. Assess the indications, contraindications and precaution of hydrotherapy. 6. Choose and use the most appropriate hydrotherapy treatment technique to have desired treatment goals. Structure of the Skin The skin is the largest human organ. It covers between 1.5 and 2 m2, comprising about 16% of total body weight. Distribution of skin thickness varies for different body parts. It is 10 times as thick on the palm of the hand as compared with other body areas. The skin is the organ, which is of main concern in water applications since it lies between the body and the environment. It shields the body from the extremes of heat and cold and is able to protect the body from injury because: It is waterproof, elastic, pliable & durable. It transmits stimuli to the central nervous system (C.N.S). It mirrors the general bodily functions and gives clues to the state of the person's health. Normal skin feels stimuli quickly; it is clear feels elastic warm and smooth. As the individual ages; the skin became atrophic and degenerative changes occurs. The skin performs a complex role in human physiology: Serves as a barrier to the environment, and some glands (sebaceous) may have weak anti-infective properties. Acts as a channel for communication to the outside world. Protects us from water loss, friction wounds, and impact wounds. Uses specialized pigment cells to protect us from ultraviolet rays of the sun. Produces vitamin D in the epidermal layer, when it is exposed to the sun's rays. Helps regulation of body temperature through sweat glands. Provides sensory reception. Helps regulation of metabolism. Composition of the Skin: The skin is composed of two main layers: 1 - The surface epithelium (the epidermis). 2- The subjacent connective tissue layer (the dermis). 1. The epidermal layers: As the outermost skin layer, the epidermis forms the actual protective covering against environmental influences. Its thickness averages 0.1 mm. On the face it is only 0.02 mm, while on the soles of the feet between 1 and 5 mm. It is non-vascular& consists of epithelium cell. The epidermis has several strata (layers) that contain four cell types: Keratinocytes produce keratin, a protein that gives skin its strength and flexibility and waterproofs the skin surface. Melanocytes produce melanin, the dark pigment that gives skin its color. Merkel's cells are probably involved with touch reception. Langerhans' cells help the immune system by processing antigens (They engulf foreign material that invades the epidermis and migrate out of the skin to stimulate an immune response). 2. The dermal layers: The dermis, called "true skin", is the layer beneath the epidermis. It contains living cells, a great density of blood vessels that are related to both nutrition of the skin and to its thermoregulation. Its major parts are collagen (a protein that adds strength), reticular fibers (thin protein fibers that add support), and elastic fibers (a protein that adds flexibility). Structure of the skin The dermis has two layers: the papillary layer, which has loose connective tissue, and the reticular layer, which has dense connective tissue. These layers are so closely associated that they are difficult to differentiate. The papillary layer lies directly beneath the epidermis and connects to it via papillae (finger-like projections). Some papillae contain capillaries that nourish the epidermis; others contain Meissner's corpuscles, sensory touch receptors. The reticular layer contains criss-crossing collagen fibers that form a strong elastic network. This network forms a pattern called cleavage (Langer's) lines. It also contains Pacinian corpuscles, sensory receptors for deep pressure, sweat glands, blood and lymph vessels, smooth muscle, and hair follicles. The hypodermis (subcutaneous layer): It lies beneath the dermis. Loose connective tissue which in many places is transformed into subcutaneous adipose tissue. It insulates the body, conserving heat. The hypodermis is loosely connected to underlying deep fascia, or periosteum. It also contains blood vessels, lymph vessels, and the bases of hair follicles and sweat glands. The fat distribution in this layer gives the female form its characteristic curves. The skin is continuous, with several mucous membranes e.g. at the lips, eyelids & anus Pigmentation of the skin: The melanin pigmentary system is composed of functional units called epidermal melanin units. Each unit consists of a melanocyte that supplies melanin pigment to a group of keratinocytes (about 36). Pigmentation is determined primarily by the amount of melanin transferred to the keratinocytes. enzyme Tyrosine (amino acid) melanin. Dopoxidase This reaction is accelerated by ultraviolet. Melanin keeps excessive ultraviolet rays from burning the skin. Glands: Two main glands are embedded in the dermis 1- Sebaceous glands: They secrete fatty substances called Sebum, which waterproof the skin and lubricate it. They are all over the body except on the palms of hands and soles of feet. The glands empty via ducts into the bases of hair follicles and secrete sebum (a mixture of fats, waxes, and hydrocarbons). Sebaceous glands are numerous on the face and scalp. 2- Sweat glands: They reach the skin surface by way of ducts and openings called pores. These pores don't open and close. Sweat is able to be act as a lubricant. There are two types of sweat glands. a) The apocrine sweat glands fail to open directly onto the skin surface, but drain into large hair follicles. They are located near the armpits and around the genitalia. b) The eccrine sweat gland, are distributed over the skins entire surface. The secretion of the apocrine differs to that of the eccrine; it is thick and creamy in contrast to the watery solution of the eccrine glands. These glands aid in the removal of dirt and oil from the pores, help to regulate body temperature and also maintain the skin's PH balance. Circulation of the Skin Circulation through the skin serves two functions: A- Nutrition of the skin tissue. B- Regulation of body temperature by conducting heat from the internal structures of the body to the skin, where it is lost by exchange with the external environment (by convection, conduction and radiation). The cutaneous circulatory apparatus is well-suited to its functions. It comprises two types of vessels: 1- The usual nutritive vessels (arteries, capillaries and veins). 2- Vascular structures concerned with heat regulation. They include: C- An extensive subcutaneous venous plexus which can hold large quantities of blood (to heat the surface of the skin). D- Arteriovenous anastomoses which are large direct vascular communication between arterial and venous plexuses. Arteriovenous anastomoses are only present in some skin areas which are often exposed to maximal cooling, as the volar surfaces of hands and feet, the lips, the nose and the ear. Circulation of the skin The specialized vascular structures just mentioned, bear strong muscular coats innervated by sympathetic adrenergic vasoconstrictor nerve fibers. When constricted, blood flow into the subcutaneous venous plexus is reduced to almost nothing (minimal heat loss); while, when dilated, extremely rapid flow of warm blood into the venous plexus is allowed (maximal heat loss). The rate of cutaneous blood flow required to regulate body temperature varies in response to changes in the metabolic activity of the body and/or the temperature of the surroundings. Exposure to extreme cold reduces the rate of blood flow to very low values, so that the nutritive function may sometimes suffer. On the other hand, heating the skin until maximal vasodilatation occurs (as in hot climate), increases the cutaneous blood flow 7 times the normal value (2.8L/min.). This diminishes the peripheral resistance and increases the cardiac output, which may lead to the decompensation of the heart in borderline-heart-failure subjects exposed to hot weather. *The triple response: A firm stroke applied to the skin results in three local reactions collectively known as the triple response: (a) At first blanching of the skin occurs for a very brief moment (due to pressure exerted by the stroke), followed by a red line due to capillary dilatation (caused by histamine and other mediators of vasodilatation released from damaged tissues). (b) A red flare follows the red line by 20-40 seconds and is due to arteriolar dilatation through a local axon reflex (the axon reflex is caused by stimulation of the pain nerve fibers with impulses passing up these fibers and down to their endings where vasodilator algogenic--i.e, pain-inducing--substances are released). (c) finally, a wheal may appear after 1 minute, reaching full development within 5 minutes (the wheal is best seen in people with hypersensitive skin; it is due to release of histamine which causes arteriolar dilatation and venular constriction, raising the capillary blood pressure with transudation of fluid into the tissues). Types of Sensation a) Exteroceptive sensations (cutaneous sensations): Are those from the surface of the body (skin) as touch, temperature and pain senses. Sensory receptors of the skin include: mechanoreceptor, thermo-receptors and pain receptors. In this course of electro and hydrotherapy we shall deal chiefly with cunteneous sensations. b) Proprioceptive sensations (deep sensation): Include senses of position and movement. It also includes sensations from deeper tissues, muscles, tendons and joints. c)Visceral Sensations: Sensations from viscera of the body as visceral pain, sense of micturation and defecation. Sensation of the Skin: The skin is innervated with around one million afferent nerve fibers. Most terminate in the face and extremities; relatively few supply the back. The cutaneous nerves contain axons with cell bodies in the dorsal root ganglia. There are special cutaneous nerve endings or receptors for touch, pressure, temperature, and pain terminate in the epidermis. The pain receptors are just free nerve endings. These nerves transmit stimuli, to the brain insuring that the body is made aware of environmental conditions. Sympathetic nerves control the sweat glands, hair follicles (goose flesh) and the wall of blood vessels. Receptors of the Skin Specificity versus pattern theory of pain (A), Specific for each type of sensation (B), Pattern of action potentials resulting in sensation of pain. Meissner's corpuscle These touch receptors are especially effective in detecting light touch and soft, fleeting movements. Pacinian corpuscles These function as receptors for deep pressure and vibration Free Nerve Endings These are derived from non-myelinated fibers occur in the superficial dermis and in the overlying epidermis; they are sensitive to pain, temperature changes and itchiness. They detect changes in the external or internal environment and inform the central nervous system of such changes along afferent nerves in the form of action potentials (impulses).Receptors act as detectors for energy changes in the environment and transducers as they transform this change to electrical impulses. There is intrinsic feedback system those found directly with in skeletal muscle tissue or nearby and extrinsic feedback system located outside skeletal muscle .e.g. ligaments, joint capsules, skin. Types of Receptors Mechanoreceptors: These receptors respond to mechanical form of energy. They detect mechanical deformation e.g. touch, pressure. Thermoreceptors: Detect temperature changes, some for cold and warmth. Chemoreceptors: These receptors respond to chemical changes in the environment e.g. small receptors, taste receptors. Electromagnetic receptors: These receptors detect light on the retina of the eye. Nociceptors: These are pain receptor which respond to any form of energy destroys the tissues, e.g. deep pain, superficial pain (cutaneous pain) and visceral pain. *Points to be remembered about receptors: -Most of the activity of the nervous system is produced as a result of stimulation of the receptors. -Impulses from the receptors may lead to immediate reaction or ascend to the brain leading to perception of particular stimulation. Integrating center Afferent Efferent Receptor Effector Stimulus Response Feed back Stimulus is a detectable change in the environment. Each type of receptor is most sensitive to a particular from of energy ( specificity of receptors ) i.e. there a specific adequate stimulus for each receptor . -As the intensity of increased. the stimulus increase the receptor potential Types of nerve fibers Definition of hydrotherapy Hydrotherapy, derived from the Greek wards hydro and therapeia meaning water and healing, is the application of water, either internally or externally, for the treatment of physical or psychological dysfunction. Or It is the use of water at different temperature in any of its forms (solid, liquid or vapor) and in different ways (internally or externally) in the treatment of disease or trauma. The healthy human body maintains a normal uniform physiological stability within and among its parts, known as homeostasis. To preserve this homeostasis, the body must continually make physiological adjustments to many environmental influences. Factors that can affect the physiological process within the human body: 1. Seasonal changes 2. Temperature 3. Atmospheric pressures 4. Rainfall 5. Sunlight 6. Various radiation 7. Clothing 8. Food and water The ease with which heat could be lost from the body has a definite effect on various bodily functions such as growth and reproduction, the production of antibodies, resistance to infection, metabolism and even the mental activity. In hydrotherapy, the environment of the body is changed by means of water, which may be at varying temperature and could be applied by various mechanical means. In general, the physiological responses are in direct proportion to the extent of the environmental changes. Benefits of hydrotherapy The goal of hydrotherapy is to improve the circulation and quality of blood. This is important, since blood deliveries nutrient to and remove the waste products from the tissues and organs. If circulation is poor or slow, healing nutrients could not be delivered and toxins could not be removed, which causes degeneration of tissues and organs. By improving the quality of blood, more nutrients are available for cells to use and toxins are managed more efficiently. Basics of heat transfer Heat transfer is concerned with two things; temperature (the amount of thermal energy available) and the heat flow (the movement of thermal energy from place to place). Mechanism of heat transfer There are many methods of heat loss or heat transfer; conduction, convection, conversion, radiation and evaporation. 1. Conduction: Heat transfer by direct contact such as hot packs and cold packs 2. Convection: Heat transfer by circulation of a medium of a different temperature such as Fluidotherapy, Whirlpool, Blood Circulation 3. Conversion: Conversion from one type of energy to another such as Ultrasound Diathermy, and metabolism 4. Radiation: Exchange of energy directly without an intervening medium such as Infrared Lamp 5. Evaporation: Absorption of energy as the result of conversion of a material from a liquid to a vapor state such as vapocoolant sprays. Regulation of body temperature The rate of heat production usually balances the rate of heat loss. The thermostatic control of temperature occurs in neural centers in the spinal cord and in the hypothalamic region. Reflex and semi-reflex thermoregulatory centers include autonomic, somatic, endocrine and behavioral patterns. Reflex responses activated by the cold are controlled from the posterior hypothalamus, while those activated by warmth are controlled from anterior hypothalamus. *Some terms related to sensations: Heat …………..……...is a form of energy that could be transferred from a body of high temperature to a body or environment of lower temperature. Hyperemia………………. is an increased content of blood Anesthesia: ........................ is complete loss of sensation. Hypoalgesia: ..................... is diminished pain sensibility. Hyperalgesia: .................... is increased pain sensibility. Analgesia:...........................is loss of temperature sensation. Hypothermaesthesia: ........ is diminished temperature sensation. Therapeutic properties of water Water has unique therapeutic properties, which include physical and chemical prosperities that make it well –suited to a variety of rehabilitation application. A) Physical properties: These properties include: 1) high specific heat and thermal conductivity 2) Bouncy 3) resistance 4) and hydrostatic pressure 1) Specific heat and thermal conductivity Water can transfer heat by conduction (stationary water) and convection (moving water) and can therefore be used as a superficial heating or cooling agents. It is effective for this application because of its high specific heat and thermal conductivity Specific heat of water means that it takes one calorie of heat to raise the temperature of one gram of the material one ◦C. The specific heat of water is approximately four times that of air and its thermal conductivity is approximately 25 times that of air. Thus it transfers the thermal energy 25 times more rapidly than air at the same temperature. Clinical benefits: Clinically, during hydrotherapy, heat is generally transferred from warm water to a patient by placing the patient's limb in warm water. Heat may also be transferred from the patient to cooler water by immersion of a limb or part of it in cold or ice water. 2) Bouncy o Bouncy is a force experienced as an upward thrust on the body in the opposite direction of the force of the gravity. o According to Archimeds' principle, when a body is entirely or partially immersed in a fluid at rest, it experiences an upward thrust equal to the weight of the fluid it displaces. o The amount of the fluid it displaces depends on the density of the immersed body relative to the density of the fluid. o If the density of the immersed body is less than the density of the fluid then it displaces smaller volume of fluid and will float and vise versa. o Men have a higher density than women because of a higher muscle –to-fat ratio (muscle density >fat density). Therefore, women have more bouncy than men. Clinical benefits Bouncy of the body in water can be used clinically to: o Decrease stress and compression on weight –bearing joints, muscles, and connective tissues o Raise weakened body parts against gravity. o Assist the therapist in supporting the weight of patient's body during therapeutic activities. 3) Resistance o Viscosity (internal friction between the molecules) and cohesion (attractive force exerted by each molecule on those surrounding) of the water provide resistance to the motion of a body in water. o Resistance occurs in the against direction of the motion of the body and increase in proportional to the relative speed of the body's motion and the frontal area of the body part(s) in contact with water. Clinical benefits o The velocity-dependant resistance provided by water makes it a safe and effective strengthening medium for many patients. o Variable resistance and pressure provided by moving water can be beneficial for debriding and cleansing wounds. 4) Hydrostatic pressure o Hydrostatic pressure is the pressure exerted by a fluid on the body immersed in the fluid. o According to Pascal's law, a fluid exerts equal pressure on all surfaces of the body at rest at a given depth, and this pressure increase in proportion to the depth of the fluid. Clinical benefits o Immersion in water can assist in promoting circulation or alleviating peripheral edema due to venous or lymphatic insufficiency. o Facilitate cardiovascular function o Support provided by hydrostatic pressure may help to brace unstable joints or weak muscles. o The greatest effect will occur with vertical positioning. o The effect will be less pronounced if the patient is swimming in more horizontal position close to the water surface. o There are also no hydrostatic pressure effects when non-immersion hydrotherapy techniques are used. N.B" Bouncy, resistance and hydrostatic pressure can be also called mechanical properties of water B) Chemical properties: This is not a property of water itself but of the gases or solids which it may contain. N.B: Conversion from centigrade (C) to Fahrenheit (F) & vise versa: C to F: Multiply by 9/5 and add 32 e.g ; (9/5x 37ºC)+32= 98.6 ºF F to C: subs tract 32 and multiply 5/9 e.g ; (98.6ºF- 32) x 9/5= 37ºC Physiological effects of hydrotherapy I. General physiological effects The physiological effects of water are the results of its physical (thermal and mechanical) properties and include: System 1) Musculoskeletal system 2) Cardiovascular system 3) Respiratory system 4) Renal system 5) Psychological aspects Physiological effects o o o o Decrease weight bearing Strengthening Slowed bone density Less fat loss than other forms of exercise Increase venous circulation o Increase cardiac volume o Increase cardiac out put o Decrease heart rate, systolic blood pressure, and Vo2 response to exercise. o Decrease vital capacity o Increased work of breathing o Decreased exercise induced asthma o Diuresis o Increased sodium and potassium excretion o Relaxing or invigorating depending on temperature. 1) Musculoskeletal effects The bouncy of water unloads the weight-bearing anatomical structures allow patients with load –sensitive joints to perform exercises with less trauma and pain. This effect can help patients with arthritis, ligamentous instability, and other degenerative or traumatic conditions. Bouncy can also be helpful for obese patients for whom land based exercise places extreme stress on the weight bearing joints. Velocity –dependant resistance provided by water can be used to provide a force against the working muscle in order to gain or maintain strength. For example , water based exercises increase upper and lower extremity strength in patient with neuromuscular diseases and maintain strength in healthy individuals. The hydrostatic pressure exerted by water increase resting muscle blood flow by 100% to 225% during immersion of the body up to neck improve muscular performance by increasing oxygen availability removal of waste product effective muscle training 2) Cardiovascular effects The cardiovascular benefits of hydrotherapy are due to the effects of hydrostatic pressure. The hydrostatic pressure displaces the venous blood proximally from the extremities enhances venous return by shifting blood from the periphery to the trunk vessels and then to the thorax and the heart. With immersion to the neck, central blood volume increase by about 60% and cardiac volume increase by nearly 30%. The velocity-dependant resistance to motion provided by water also Increase the metabolic rate and energy expenditure, as measured by Vo2, approximately a factor of 3 when an activity is performed at the same speed in water as on dry land. 3) Respiratory system Immersion of the whole body in water increases the work of breathing because of the shift of venous blood from the peripheral to the central circulation increase the circulation in the chest cavity. The hydrostatic pressure on the chest wall increase to the resistance lung expansion. Immersion in water up to the neck decrease expiratory reserve volume by about 50% and decrease the vital capacity by 6% to 12%. These effects, combined, increase the total work of So breathing by about 60%. exercise in water can improve the efficiency and strength of the respiratory system. Water based exercise is also recommended for patients with exercise induced asthma because of various properties of water: Absence of pollen over of the water Hydrostatic pressure on the chest Hypoventilation Peripheral vasoconstriction And high humidity of the inspired air in the pool environment. 4) Renal effects Immersion of an individual up to the neck in water increase urine production and urine, sodium , and potassium excretion. These effects are the results of: Increased renal blood flow and decreased antidiuretic hormone (ADH) and aldosterone production. 5) Psychological Effects Psychological effects depend on the temperature of the water Soaking in warm water is generally relaxing Cold water immersion is found to be invigorating and energizing. 6) Central and peripheral nervous system Pain modulation. Relaxation effect. II. Physiological effects of heat application (Thermo therapy) Therapeutic application of heat is known as thermotherapy Therapeutic heat………40ºC to 45ºC More than45ºC………..tissue damage. Less than 40ºC………..mild heating. 1. Hemodynamic effect (effect on vascular bed) Dilatation of the blood vessels (vasodilatation) leads to hyperemia and sweating. Mechanism of vasodilatation a) Direct reflex activation of smooth muscles of blood vessels by cutaneous thermoreceptors. b) Indirect activation of spinal cord reflexes by cutaneous thermoreceptors or by increasing the local release of chemical mediators of inflammation. Temperature Inflammation Vasodilators (histamine+ prostaglandin) release cutaneous thermoreceptors spinal cord dorsal root ganglion smooth muscle relaxation Sympathetic adrenergic activation Vasodilatation How heat cause vasodilatation With maximal vasodilatation there are: Rise in pulse rates. Drop in blood pressure Profuse sweating with chloride loss Increase fluid transfer across the capillary wall with increased removal of tissue metabolites. 2.Neuromuscular effects (on muscles and nerve) 1) On muscles: a) Relaxation: This occurs when the warm blood reaches deeper and deeper into the muscles causing the vessels to expand. Relaxation relieve of pain by easing any pinching of nerves or blood vessels and by helping the muscles to remove lactic acids and other metabolic wastes. Relaxation in ROM allowing for gentle exercises and stretching. b) Increase blood flow Heat increase blood flow in the muscles this is beneficial in muscle spasm or sustained contractions where ischemia may contribute to the pain. 2) On nerve Analgesia on the peripheral and central nervous system. Sedative action: as the body tries to register a temperature change, the central nervous system becomes depressed, contributing to muscle relaxation and temporarily relieve of pain. The thermal stimulus that affects the pain sensation is explained by the gait control theory of pain. 3.Effect on connective tissues Heat and stretch could alter the viscoelastic properties of the connective tissues. Heating decreases joint stiffness and increase tissue extensibility. 4. On the whole body Rise body temperature. Increased pulmonary ventilation. Increased metabolism: 10 ºC increase in the temperature will twice or triple the metabolic rate leading to an increase of oxygen uptake, an increase of nutrients and promotion of healing. Reflex effect of prolonged heat Prolonged heat to one extremity causes vasodilatation of the contra-lateral extremity. Prolonged heat to the abdominal wall causes a decreased in the intestinal blood flow, diminish in the intestinal motility and decrease in the secretion of acid in the stomach. Prolonged heat to the pelvis relaxes the musculature of the pelvic organs, dilates the blood vessels and increases menstrual flow. Prolonged moist heat to the chest promotes ease of respiration and expiration. Prolonged heat to the trunk, such as a hot trunk pack, relaxes the ureters or bile ducts and relieves renal or gallbladder colic. Prolonged moist heat to the area over the kidneys in the back and over the lower abdomen in front increases the production of urine. III. Physiological effects of cold application (Cryo therapy) 1.Hemodynamic effect (effect on vascular bed) Cold application causes an immediate constriction of the cutaneous blood vessels and a reduction in blood flow. a) Initial decrease in blood flow If cold is applied to the skin, it causes an immediate constriction of the cutaneous vessels and a reduction in blood flow. This vasoconstriction persists as long as the duration of the cold application is limited to less than 15 to 20 minutes. Mechanism of vasoconstriction Direct reflex activation of smooth muscles of blood vessels by cutaneous cold receptors. Indirect : by decreasing the production and release of vasodilator mediator, such as histamine and prostaglandins, resulting in reduced vasodilatation. Decreased the tissue temperature also cause reflex activation of sympathetic adrenergic neurons vasoconstriction Cold reduce the circulatory rate by increasing blood viscosity Increasing the resistance to flow. b) Later increase in blood flow When cold is applied for longer period of time or when tissue temperature reaches less than 10ºC (50ºF) vasodilatation may occur. This phenomenon is known as cold-induced vasodilatation (CIVD). Hunting response: Following the application of intense cold to the body there was vasoconstriction with liberation of histamine- like (H) substance produced by the intense cold and noxious stimuli. When there were sufficient H substances vasodilatation occurred for about 4 to 6 minutes remove all H substance vasoconstriction was established again, with vasodilatation occurring at further intervals of 15 to 30 minutes. The sudden vasodilation due to intense cold application is termed the (hunting response). The initial vasoconstrication lasts about 9 to 16 minutes. lewis also stated that the after- effect following removed of intense cold for a prolonged period was vasodilation which increased for 20 minutes then subsided slowly. Temperature blood viscosity Vasodilator (histamine +prostaglandin) release cutaneous thermoreceptors smooth muscle contraction vasoconstriction spinal cord dorsal root ganglion sympathetic adrenergic activation blood flow How cold (cryotherapy ) decrease blood flow 2.Neuromuscular effects (on muscles and nerve) 1)On muscle: a) Altered muscle stretching: depending on the duration of the treatment and the time of measurements, of cryotherapy has been associated with both decrease and increase in muscle strength. Isometric muscle strength increase directly after the application of ice massage for 5 minutes or less due to facilitation of motor nerve excitability and an increased psychological motivation to perform. In contrast after cooling for 30 minutes isometric muscle strength decreased and then increased an hour later, to reach greater than pre-cooling strength for the following 3 hours or longer. The proposed mechanism: prolonged cooling reduction of blood flow to the muscles, slowed motor nerve conduction, increased muscle viscosity and increased joint or soft tissue stiffness. b) Decreased spasticity: cold can temporarily decrease spasticity Two mechanisms are involved: first, a decrease in gamma motor neuron activity and later a decrease in afferent spindle and Golgi tendon organ activity. c) Facilitation of muscle contraction: brief application of cryotherapy facilitate alpha motor neuron activity to produce a contraction in a muscle that is flaccid due to upper neuron dysfunction 2) On nerve Analgesia due to de-sensitivity of nerves: local cold application has numbing, analgesic or anesthetic effect. This has been used for the relief of certain types of acute pain, such as acute joint pain, pain of acute bursitis, sprains and other acute trauma and burn pain. Prolonged exposure damage to the nerve may be result. 3.Metabolic effects Cold decrease the rate of all metabolic reactions, including those involved in inflammation and healing. Thus Cryotherapy can be used to control acute inflammation. Segmental relations of skin and viscera Organs Heart and Aorta Lungs Stomach Intestines Liver and Gallbladder Kidneys Segments Dorsal 1-4 Dorsal 1-7(2-5 most) Dorsal 7-9 Dorsal 9-11 Dorsal 3, 6-9 Dorsal 10 to lumber 1 Bladder Mucosa Testis Bladder muscles Uterus; Upper portion Uterus; Lower Portion Sacral 3-4 Dorsal 10 Dorsal 11 to lumber 1 Dorsal 11,12 Sacral 3-4 Factors affecting the physiological effects of heat and cold 1. Water temperature 2. Difference between the temperature of water and the skin, i.e if one hand is placed in hot water and the other in cold water, then both in luke warm water, there will be a sensation of hot to the hand that was first in cold water. 3. Mechanical impact of water, i.e. showers, sprays. 4. Suddenness of application (rapid or slow) 5. Surface area to be treated (the larger the area the more receptors stimulated and the greater the physiological effects). 6. Age and general heath of the patients 7. Duration and frequency of the treatment Indications, contraindication and precautions of hydrotherapy Main indications or clinical uses of hydrotherapy 1. 2. 3. 4. 5. 6. Relief of pain Relief of muscle spasm Improve circulation Mobilization and under water exercises General sedation reducing nervous excitability Treatment of spacticity either through reciprocal inhibition (brief icing on the antispastic muscles) or direct inhibition (long icing over the spastic muscles or warm application over the spastic muscles. 7. Local anesthesia (icing) Hydrogymnastics (Under water exercises) Definition: Hydrogymnastics or pool therapy or underwater exercises are exercises in water. Thy differ from apparently similar exercises in air because of the difference in physical properties of two mediums. Types of water exercises 1. 2. 3. 4. 5. Swimming Running with or without a vest or belt Walking Cycle ergometry And other forms of upright exercise can be performed in water Uses of water exercises A) General uses B) Specific uses A) General uses: To increase Circulation Muscle strength Joint viscoelasticity Flexibility Range of motion (ROM) To improve Ambulation Coordination Cardiovascular and respiratory conditioning Psychological conditioning B) Specific uses Problems Effects Orthopedic problems Decrease weight bearing on joints Velocity dependant resistance Closed or open chain exercises Neurological problems Cardiac fitness Exercise in water during pregnancy Exercise induced asthma Slowed bone density loss Proprioceptive input Increased safety Improved balace Cardiac conditioning in patients with poor tolerance for land-based exercises Decrease weight bearing Less elevation of heart rate with exercise Decreased risk of maternal hyperthermia Less exercise-induced asthma than with other forms of exercise