SvedanaDravya has its main actions like Stambhaghna, Gauravaghna, Sītaghna and SvedaKārakatva

स्तम्भगौरवशीतघ्नंस्वेदनंस्वेदकारकम्||

                                                                         ( Cha. Su 22/11)

 Sedative effect

The sedative effect produced relieves the pain in area. This may be because of the increased blood supply which produces removal of waste products hence getting a good nourishment. Heat is also a counter irritant ie the thermal stimulus may effect the pain sensation as explained in pain gate theory of Melzack and Wall. This explains the effect of heat applied on the nerves. Vāta is the responsible factor for inducing painin the body and the properties of Vāta and Svedana are exactly the opposite. Hence the heat can cause reduction in pain by reducing the swelling, removing the coldness at the site and causing perspiration.

Relieves Stiffness (Staṃbha)

Stiffness is a resultant of excess SītaGuṇa. Vāyu by RūkṣaGuṇaabsorbs Snigdhatāwhich results in Staṃbha. Svedana byits Snigdha and Uṣṇa property relieves Staṃbha. UṣṇaGuṇa of Svedana doesSrotośuddhi and Āmapācana and relieves stiffness. Rise in temperature induces muscle relaxation and increases the efficiency of muscle action, as the increased blood supply ensure the optimum conditions for muscle contraction.

Relieves Coldness

This is mainly due to UṣṇaGuṇa of Sveda. As a result of the increased metabolism, the output of waste products from the cells is increased. These include metabolites, which act on the walls of capillaries and arterioles causing dialation of these vessels. In addition, the heat has a direct effect on the blood vessels, causing vasodilatation, particularly in the superficial tissues where the heat is more. Stimulation of superficial nerve endings can also cause a reflex dilatation of the arterioles. As a result of the vasodilatation there is an increased flow of blood through the area, so that the coldness of body gets removed.

Relieves heaviness

Svedana relieves heaviness in the body. Heaviness is reduced due to KaphaVilayanaby Uṣṇa and LaghuGuṇa of Svedana.

Stimulation of sweat glands

Svedana promotes sweating. There is reflex stimulation of the sweat glands in the area exposed to the heat, resulting from the effect of the heat on the sensory nerve endings.  As the heated blood circulates throughout the body it affects the centres concerned with the regulation of temperature and there is increased activity of the sweat glands throughout the body

Relieves obstruction of channel

The Heat has a direct effect on the blood vessels, causing vasodilatation, particularly in the superficial tissues where the heat is more. Stimulation of superficial nerve endings can also cause a reflex dilatation of the arterioles. As a result of the vasodilatation there is an increased flow of blood through the area, so that the necessary oxygen and nutritive materials are supplied and waste products are removed. Thus channels get cleared. SvedanaKaṛmahelps to dissolve Kaphawhichis in dense stage (Grathita) stuck to the channels firmly by itsUṣṇa, TīkṣṇaGuṇa. FurtheritliquifiesKaphaallowingit to move freely.

Agni dīpana

As SvedanaisUshnaGuṇaPradhana, itstimulatesAgni and hencedoes the ĀmaPācana.

TvakMārdava

Mechanism of sweat involves the skin, where in hairfollicles, the Mūlaof SvedavahaSrotasare situated. Due to Sweatingand excretion, skin becomes soft and pleasant.

स्निग्धस्यसूक्ष्मेष्वयनेषुलीनंस्वेदस्तुदोषंनयतिद्रवत्वम्

                                                                                    (Cha. Si. 1/8)

Svedana helps to liquify the vitiated Dōṣas that have spread throughout the microchannels of the body.

Mode of action of ŚodhanāṅgaSveda

स्नेहक्लिन्नाःकोष्ठगाधातुगावा
स्रोतोलीनायेचशाखास्थिसंस्थाः|
दोषाःस्वेदैस्तेद्रवीकृत्यकोष्ठं
नीताःसम्यक्शुद्धिभिर्निर्ह्रियन्ते|                            (A. H. Su 17/29)

The anointed Doṣaswhich were lodged at different regions of peripheral parts, gets liquefied by sudation therapy were brought back to the central part of the body for easy elimination by the appropriate Śodhanamethods.

Steam Bath

Steam bath is current sudation technique in which sweating is induced. It not only helps in relaxing and renewing energy but also promotes health and beauty as well. The moist heat stimulates the subcutaneous blood flow and cleanses the skin intensively, opening the pores, removing dead skins and impurities and leaving the skin feeling soft, clean and smooth

Physiological effects

Sweating is the only way to lose heat when the environmental temperature exceeds that of the body. The body cannot maintain a constant temperature when the environmental temperature is as high as that reached in a steam bath and so the body temperature begins to rise. The rise in body temperature depends mainly on

1. The temperature and humidity content of steam bath
2. The sweating capability of the bather, and
3. The bathing times

The body temperature has been found to rise from 37.6⁰C to 40⁰C

The physiological changes that occur during the bath are due in part to rise in body temperature and in part to the influence of the reflexes of the hormonal and nervous systems, which attempt to increase the heat loss

Effects of steam bath

Steam bath is especially recommended to alleviate the conditions such as:

• Bronchial asthma
• Bronchitis
• Catarrh of upper respiratory tract
• Cough
• Hoarseness of voice
• Expectoration
• Non acute rheumatic complaints
• Restricted or painful movements of joints
• Sleeping disorders
• Poor skin circulation and for dry chapped skin
• Muscular weakness in subcutaneous blood vessels

How to take steam bath

• Patient should be subjected to shower before first session
• Time of stay in steam bath is in accordance with personal sensitivity of patient
• Do not exceed 15 to 20 mins
• Cool off with cool fresh air and cool water without shocking the system and avoid shivering
• Subject patient to warm foot bath if the patient has cold feet

Sauna bath

A sauna is a small room or building defined at a place to experience dry or wet heat sessions, or an establishment with one or more of these facilities.

Saunas are of 2 basic types

• Conventional saunas that warm the air
• Infrared saunas that warm objects (charcoals, active carbon fibres)

How to give sauna bath

• Ask patient to undress in dressing room
• Ask patient to drink 1-2 glass of water or any sport drink (avoid caffeine) which has electrolytes
• Patient should be subjected to shower first
• Do not give sauna bath for over 10-15mis
• Ask patient to exit sauna if he feels uncomfortable or become sleepy
• Cool off with cool fresh air and cool water without shocking the system and to avoid shivering
• Give a warm foot bath if the patient has cold feet and then repeat the session
• Don’t give more than 3 sessions at a time in the sauna bath

Benefits of sauna bath

• Increases circulations to extremities
• Provides cardiovascular workout
• Brings nutrients for healthy skin
• Stimulates immune system
• Increases energy levels and brings restful sleep
• Opens skin pores, soothes sore muscles and increases circulation

Precautions for sauna bath

• Do not use alcohol prior to or during a sauna bath
• Drink plenty of water before and after sauna bath
• Limit sauna or steam time to 15mins
• Do not eat any large meals before sauna
• Contraindicated in low blood pressure, pregnant women, children
• Should not be used as a weight loss aid by itself
• Give at least 20mins rest, before sauna, after a workout to avoid heatstroke

Complications

• Fatigue
• Dizziness
• Vertigo
• Rapid heart beat

INFRARED THERAPY

Infrared rays are electromagnetic waves. It lies between visible light and microwaves. Wavelength is 750nm to 400000 nm.

TYPES OF IR LAMPS

Two types of infrared sources are:

1. Non-Luminous generators
2. Luminous generators

NON LUMINOUS GENERATORS

It is also known as low temperature generators. Produces only infrared rays of wavelength 750 nm to 15000nm. These generators are heated by passage of electric current through a carbon held in a non conducting material like porcelain, mounted in the centre of parabolic reflector. For recent injury, this type of generator is useful.

LUMINOUS GENERATORS

It is also known as high temperature generators. Emits visible rays, ultraviolet rays

And infrared rays of wavelength 350 nm to 4000 nm. The filament is made of tungsten. In chronic diseases it is used.

PHYSIOLOGICAL EFFECTS

Increases metabolic rate

Cutaneous Vasodilatation

Stimulation of thermal heat receptors

COMPLICATION

Burns

Electric shock

Faintness

Headache

Gangrene

Injury to the eyes

Dehydration