Excessive exposure to ultraviolet rays can burn the skin, or cause senile cataracts and even skin cancer. But moderate ultraviolet rays have many benefits to the human body:
There is a basal cell in the human epidermis, which contains "melanogen", which is a tyrosine substance. Under the action of ultraviolet rays, "melanogen" turns black and deposits on the surface of sunburned skin, making the skin evenly black and brown. This is an important cause of skin tanning. This deposited pigment can absorb more light energy, quickly convert it into heat energy, and stimulate sweat glands to secrete heat. Sunbathing can kill bacteria on the skin and prevent skin diseases such as boils and folliculitis. Indoor sun exposure and frequent bedding exposure can reduce the spread of diseases.
Promote calcium and phosphorus metabolism There are sterols in human skin, which can be converted into vitamin D under the ultraviolet irradiation of sunlight. Vitamin D can improve calcium and phosphorus metabolism after entering the blood, and has the effect of resisting rickets, osteomalacia and senile osteoporosis.
Enhance the body's immunity. Ultraviolet irradiation in sunlight can stimulate the hematopoietic function of human body, increase the number of red blood cells and hemoglobin, improve the quality of red blood cells, improve muscle activity, reduce blood pressure, blood sugar and cholesterol, enhance human immunity, promote the oxygen absorption capacity and metabolism of human cells, relieve asthma and joint pain, relax muscles and promote blood circulation, and enhance physical fitness.
So, when should I receive ultraviolet radiation? In midsummer, it is not advisable to expose to the sun at117, because the infrared ray is too strong during this period, which can generally reach more than 1.5 calories per cubic meter per minute, and the temperature generated is 37℃-45℃. In spring and autumn, 7- 10, or 15- 16, during this period, the sun has strong ultraviolet rays and weak infrared rays.
Harm of ultraviolet rays to human body
In hot summer, it is inevitable that the ultraviolet rays contained in the sun will irradiate the human body. Excessive solar ultraviolet radiation will do harm to human skin, eyes and immune system. Ultraviolet rays can destroy human skin cells, lead to wrinkles and spots, make the skin aging before it is old, and in severe cases, produce solar dermatitis and sunburn, or solar keratinization of skin and mucosa, which may lead to cancer. The eye is a sensitive organ of ultraviolet rays, which can damage the lens and is one of the pathogenic factors of senile cataract.
In hot summer, the sun's ultraviolet intensity is the strongest from 10 to 3 pm, so outdoor activities should be avoided to avoid the harm of ultraviolet rays to human body. Even if you need outdoor activities during this time, don't forget to hold an umbrella, wear a sun hat or sunglasses, use skin care elements and sunscreen produced by regular manufacturers, and try to wear white or light-colored clothes to reduce the unnecessary harm caused by ultraviolet rays to the human body.
Although excessive ultraviolet rays are harmful to human body, the healthy growth of human body is inseparable from ultraviolet rays. 7- dehydrocholesterol in skin is converted into vitamin D3 by light. Vitamin D3 has important physiological functions in maintaining calcium ion concentration inside and outside human cells and regulating calcium and phosphorus metabolism. In countries with insufficient sunshine, rickets in infants, osteomalacia in adults and osteoporosis are more common. Babies can't thrive without proper sunbathing, and the human body needs proper ultraviolet rays. Therefore, proper lighting is still necessary.
Infrared ray is one of the many invisible rays of the sun, which was discovered by the German scientist Huxley in 1800. It is also called infrared radiation. In the solar spectrum, the wavelength of infrared light is greater than that of visible light, and the wavelength is 0.75 ~ 1000 micron ... The infrared light can be divided into three parts, namely the near infrared light with the wavelength of 0.75 ~ 1.50μ m; Mid-infrared, the wavelength is between 1.50 ~ 6.0μ m; Far-infrared ray has a wavelength of 6.0 ~1000μ m. In recent years, due to the improvement of detection equipment and in-depth research, people have a more comprehensive understanding of the physical properties and biological effects of infrared ray, and have made a lot of progress. Infrared rays, especially far infrared rays, have been widely used in health care industry, and various infrared products related to daily life have also appeared in large numbers. This paper mainly introduces the biological effect mechanism of infrared ray and its clinical application.
First, the mechanism of infrared biological effect
Infrared ray is an electromagnetic wave. When it radiates to an object in the form of radiation, the radiant energy absorbed by the object is transferred to atoms, molecules and other particles in the object, which makes these particles move irregularly and causes the temperature of the object to rise. This is the so-called primary effect of far infrared rays, also known as warming effect. When the primary effect occurs, other chemical and physical changes also occur inside the object, which is called the secondary effect after the object absorbs far-infrared radiation, also called the secondary effect.
Infrared rays have strong penetrating power to human skin and subcutaneous tissue. The primary effect of external infrared radiation on human body is to raise the temperature of skin and subcutaneous tissue, promote blood circulation and metabolism, and promote human health [1]. The thermal effect, anti-inflammatory effect and promoting regeneration of infrared physiotherapy on tissues have been clinically confirmed. Usually, direct irradiation is used to treat diseased parts. Near-infrared micro-irradiation therapy has a significant effect on improving microcirculation, especially micro-blood flow. After irradiation, the blood flow velocity of capillaries is accelerated, the phenomenon of red blood cell aggregation is reduced, and the phenomenon of blood stasis in inferior papillary venous plexus is reduced or disappeared, which has a positive effect on improving the nutrition, metabolism, repair and function of body tissues and important organs [2].
At present, the mechanism of the secondary effect of infrared rays on human body is not completely clear.
Some scholars believe that far infrared rays can vibrate cells, mainly causing the vibration of water molecules inside and outside cells, activating cells and causing a series of biochemical and histochemical changes beneficial to health [1]. Some people think that far infrared rays with a wavelength of 8 ~ 14 micron can be called "life rays", which can significantly improve human microcirculation. When it acts on human water molecules, it can crack the aging macromolecules in the human body and recombine them into smaller water cluster. In this process, pollutants adsorbed on the surface of aging macromolecules are removed, the proportion of water increases, and water molecules attached to the surface of cell membrane increase, which enhances the activity and surface tension of cells. Due to the increase of water molecules penetrating the cell membrane, the activity of intracellular calcium ions is enhanced, thus enhancing the normal function of human cells and improving their bactericidal ability and immune ability. In addition, the light of life can also cut off the double or triple bonds of unsaturated fatty acids in blood, and saturated fatty acids are not easy to be oxidized into blood lipids [lipid peroxides], which reduces the deposition of lipids in blood vessels and smoothes the blood vessel wall, thus reducing the occurrence of cardiovascular diseases or ophthalmic diseases such as arteriosclerosis and cataract, and playing a good role in promoting human health [3].
Pang Xiaofeng studied the mechanism and characteristics of biological energy transfer released by ATP molecule hydrolysis, and thought that the biological effect and medical effect of infrared rays on organisms (including people) mainly came from the non-thermal biological effect of infrared rays. The infrared wave of 1 ~ 7 microns can penetrate the skin and reach the cells, and be absorbed by protein molecules. Protein molecules can and can only absorb or emit infrared rays with the wavelength of 1 ~ 3.5 microns and 5 ~ 7 microns, and the absorption of infrared rays in this range can lead to the quantum vibration of amide bonds in protein molecules, so that biological energy can be smoothly transferred from one place to another, making the living body in a normal state and maintaining its growth, development and health. The biological energy to maintain the normal operation of life system is provided by the hydrolysis of ATP. However, once ATP molecules or ATPase (ATP hydrolysis requires the participation of enzymes) or water is insufficient, or the structure and conformation of protein are changed or distorted, the biological energy provided is not enough to cause the normal vibration of amide bonds or the normal transfer of biological energy. Without enough energy, biological tissues can't grow normally. Can induce various diseases. In this case, if the infrared ray with the above wavelength can be absorbed by protein irradiation, protein molecules can return to normal and transmit biological energy normally, and it is possible to restore biological tissues from pathological state to normal state, thus curing diseases. The clinical test of infrared medical instruments also proves that the infrared ray which has certain medical effect on organisms or people is just within this wavelength range, that is, 0.8 ~ 1.6 micron and.
The research on the effect of infrared ray on immune function is still in its infancy. Among all infrared rays, medium-wave infrared rays are more likely to act on immune cells and promote their biological functions. The function of infrared ray is not only related to its wavelength, but also related to the number of photons it emits, that is, to the radiation intensity and radiation time. Excessive infrared radiation may also have adverse effects on the body, and its detailed mechanism needs to be further clarified. Cao Zhiran and others believe that infrared radiation has indirect and direct effects on human immune system. Indirect effect means that infrared radiation can regulate the state of other systems of the body, such as nervous system and endocrine system, so as to achieve the purpose of regulating the immune system. Direct action means that infrared rays can enhance the biological field around immune cells and immune organs after being absorbed by human body, so as to enhance their activity and mutual regulation. Infrared photons can directly act on the stimulated points of immune cells, including receptors on the surface of immune cells (such as PHA-R, TCR, L-2R, etc.). ) and some enzymes, thus activating cells and making them proliferate and differentiate [5]. Mao Wen and others speculate that the mechanism of action is that infrared rays may activate deep tissue receptors, and its physiological and biochemical effects, on the one hand, have a positive impact on the activities of biological macromolecules, cells and organs through neurohumoral reflex pathways and meridian conduction pathways that have not been fully understood at present, thus producing overall benign effects [2].
Second, the possible adverse effects of infrared rays on the human body
Thermal radiation, also known as infrared radiation, is the main feature of high temperature working environment in iron and steel metallurgical enterprises. Especially in the hot rolling and medium sintering machines of iron and steel smelting and Honggang, it is a typical infrared thermal radiation contact operation. Short-wave infrared rays with the wavelength of 0.8 ~ 1.2μ m can penetrate the cornea and enter the eyeball, aqueous humor, iris, lens and vitreous humor to absorb part of the infrared rays, resulting in cataracts, which are called "infrared cataracts" and were first seen in glass workers and iron and steel smelting workers at home and abroad. Cao Duozhi and others found that the thermal radiation hazard of iron smelting in front of the furnace is still very serious. With the increase of working years, the visual acuity decreased obviously, and the detection rate of lens opacity reached 9.46%, which was related to the distance of heat source and the working years of this position [6]. It has also been pointed out that the harm of ultraviolet rays (UVR) and infrared rays (IFR) to eyes and skin is an important aspect of occupational injury in electric welding, and ultraviolet rays and infrared rays in the process of electric welding can cause damage to cornea and lens [7].
Infrared rays in sunlight do different harm to the skin than ultraviolet rays. Ultraviolet light mainly causes photochemical reaction and photo-immune reaction, while infrared radiation causes reactions caused by molecular vibration and temperature rise. The thermal radiation caused by infrared rays can penetrate the skin more than ultraviolet rays. 25% ~ 65% of its radiation can reach epidermis and dermis, and 8% ~ 17% can reach subcutaneous tissue. Infrared rays have direct adverse effects on the skin through its thermal radiation effect, such as skin temperature rise, capillary dilation, congestion, and increased evaporation of epidermal water. Its main manifestations are red papules, premature aging of skin and pigment disorder. The skin temperature rises, the capillaries dilate and congest, and the epidermis water evaporates, which directly causes adverse effects on the skin.
Infrared rays can also enhance the damage of ultraviolet rays to the skin and accelerate the process of skin aging. Using the same sunscreen products and the same ultraviolet intensity, the SPF value (sun protection coefficient) measured in outdoor natural sunlight is obviously lower than that measured in laboratory artificial light source, which is caused by the dual effects of ultraviolet rays and infrared rays on the skin under natural sunlight. Infrared rays and ultraviolet rays have the same effect in accelerating tissue degradation. Infrared rays can also promote the development of skin cancer caused by ultraviolet rays [8].
Third, the clinical application of infrared biological effects.
Infrared rays can be absorbed by superficial tissues on the body surface, which has obvious drying and dehydration effects, accelerates the blood circulation of local tissues, and plays an anti-inflammatory and analgesic role. Clinical use of safflower oil and far-infrared radiation to treat bedsores, found that the effect is good and quick [9]. The far infrared ray was used to treat herpes zoster, and the results showed that the pain relief time, blister stop time and dementia time were shorter than those of the control group [10]. Experiments show that bioceramic far infrared rays have a significant effect on burn treatment. Chronic soft tissue injury is the best treatment for pain [1 1]. Clinical nursing observation shows that far-infrared protective devices made of ultrafine ceramic particles, such as waist protection, knee protection, elbow protection, wrist protection, collar and so on. It has obvious functions of diminishing inflammation, reducing swelling, promoting blood circulation, relieving pain, dredging meridians and improving microcirculation. Compared with wet and hot compress with magnesium sulfate, hot compress with hot water bottle and drug sealing, it has better effect and can avoid the pain caused by sealing [12]. In the past, neonatal red buttocks and ulcers were mostly prevented by washing with external disinfectant and keeping dry, which had poor curative effect and was easy to recur. Far infrared radiation and hotbed were used to treat children's red buttock and buttock ulcer. Compared with the control group, the average cure time in the treatment group is shorter and the effective rate is higher [13]. The problem of rewarming in the treatment of neonatal scleredema is an important link in the success of treatment. In the past, the effect of gradual rewarming with ordinary incubator was poor. Now, after rapid rewarming with far infrared rays, the mortality rate of children is obviously reduced and the success rate of rescue is obviously improved [14].
Skin flap necrosis is a common postoperative complication in plastic surgery, mainly caused by microcirculation disturbance, and there is no ideal prevention and treatment method at present. Ping Jiang directly observed the microcirculation changes of random skin flap on the back of rats in vivo, and discussed the influence of 2.5 ~ 15μ m band far infrared ray on the survival of skin flap. It is found that far infrared local radiation has biological effects similar to vasodilators, which can improve microcirculation and improve the survival rate of skin flap, and has no obvious side effects within the therapeutic dose range [15].
Some scholars in Japan reported that linear polarized infrared ray has obvious curative effect on various types of alopecia areata [16].
Linear polarized near infrared ray has a short course of treatment and good curative effect on temporomandibular joint pain caused by rheumatoid arthritis [17]. Compared with the traditional local nerve block therapy, the invention is used for the treatment of osteoarthritis. Although the near infrared treatment group has more times of treatment than the traditional nerve block treatment group, it has a wide range of treatment, which can avoid the pain caused by local nerve block treatment, and has high efficiency, lasting effect and is not easy to relapse. The mechanism may be that light can stimulate photoelectric energy, electromagnetic wave and photochemical action, so it can inhibit nerve excitement, relax muscles, relax blood vessels, increase blood flow, promote lymphatic circulation and promote the production of active factors, thus playing a therapeutic role [18].
Some people observed the blood viscosity of 66 patients with cardiovascular and cerebrovascular diseases before and after the treatment of low-temperature excitation of far infrared rays, and found that low-temperature excitation of far infrared rays has a wide range of biological effects, which can reduce the blood viscosity of patients with cardiovascular and cerebrovascular diseases, prevent thrombosis, improve microcirculation, and relieve chest tightness, palpitation, dizziness, numbness and other symptoms [19].
Near infrared therapy can regulate the immune function of CAH patients. SG, IgG and γ -globulin decreased, ANA and RF turned negative, SA, CH50 and C3 increased, and humoral immunity tended to normalize [20]. Infrared radiation can also promote the production of L-2 induced by Con-A, significantly improve the ADCC effect of rat spleen cells, increase the transformation rate of T lymphocytes stimulated by PHA in mice, increase the spleen index, increase the number of lymphocytes and macrophages in peripheral blood of mice [5], and also have a good effect on free radical metabolism and N K cell activity [2].
Compared with other drug therapies, infrared irradiation of bladder area is painless, does not increase postpartum hemorrhage, and is easy to be accepted by parturient. After infrared rays act on the skin, the absorbed energy is converted into heat energy, which raises the skin temperature, stimulates the thermoreceptors in the skin, relaxes the vascular smooth muscle and dilates the blood vessels through thalamic reflex, strengthens blood circulation, promotes the absorption of exudates, and is beneficial to the regression of inflammation and swelling, and relieves muscle tension and spasm, so it has obvious therapeutic effect on urinary retention [2 1].
Gai Qifeng et al. used far infrared ray with wavelength of 2 ~ 25μ m to irradiate the tenderness area of abdomen (including points of Qihai, Guanyuan and pulse) to treat pelvic inflammatory mass. 62 patients were diagnosed by clinical examination of obstetrics and gynecology and B-ultrasound, all of them had lower abdominal pain and tenderness. The gynecological examination touched cystic mass, the effective rate was 88.6%, and the total effective rate was 96.6%. Far-infrared radiation treatment of pelvic inflammatory mass can increase local microcirculation function, enhance the migration and phagocytosis of white blood cells and promote inflammatory absorption [22].
208 cases of infantile enterospasm were treated by far-infrared radiation, and it was found that its curative effect was obviously better than that of drug treatment, and it was simple and easy to operate without side effects, and the children were happy to accept it [23].
Infrared radiation can obviously alleviate hyperglycemia in diabetic rabbits, and its metabolic regulation mechanism is to inhibit the activity of cyclic nucleotide cyclase (AC), activate the activity of phosphodiesterase (PDE), hinder the synthesis of cyclic adenosine monophosphate (cAMP), accelerate hydrolysis, and reduce the level of cAMP and blood sugar [24].
The influence of far infrared rays on endogenous opioids in the brain of S 180 tumor-bearing mice was discussed through in vivo experiments. It was found that the contents of β -endorphin and leucine-enkephalin in the brain of each group of mice were significantly increased by far infrared rays. Enenkephalin-ergic intermediate neurons are thought to form axial synapses with pain afferent axons, which can have a powerful analgesic effect. This provides a theoretical basis for the clinical application of far infrared ray to treat and relieve the pain of tumor patients and relieve herpes zoster and limb pain [25].
In many diseases, the excessive production of reactive oxygen species or the decrease of antioxidant enzyme activity can cause lipid peroxidation to damage cell membrane, and then lead to cell death. Some data show that the ability of tumor host to scavenge free radicals is reduced, which indicates that the antioxidant enzymes of natural antioxidants are insufficient. Teng et al. discussed the changes of free radical metabolism in liver of tumor-bearing mice through in vivo experiments. The results showed that the activities of SOD and GSH-Px in the liver were significantly increased and the content of MDA was significantly decreased after the treatment with mid-infrared rays. MDA is the product of double bond fatty acid peroxide, and its content reflects the concentration of lipid peroxide. Due to the activation of cells, the content of MDA in liver tissue of tumor-bearing mice decreased significantly, and the activities of SOD and GSH-PX in liver increased significantly, thus enhancing the ability of tumor host to scavenge free radicals and inhibiting the growth and proliferation of tumor cells [26].
Trace elements play a very important role in the biochemical process in vivo. As an important part of various substances in the body, they are closely related to the growth and development of the body, cardiovascular and cerebrovascular diseases, immune function, and aging of the body. However, there is no definite treatment for the excess or decrease of trace elements caused by various diseases. Wang Jianjie et al. studied the effects of irradiation with a universal broad-spectrum therapeutic instrument on trace elements in the liver of mice, and found that the mid-far infrared irradiation with a peak wavelength of 7 ~ 10μ m can adjust the imbalance of trace elements in both directions, and also promote the absorption of normal contents, which plays a very good role in the prevention, treatment and health care of diseases [27].