Jeremy Madvin,Madiha Khalid

1MBA International Business,The University of Redlands,California,United States. 2Ph.D Pharmacy Sciences,Humdard University,Islamabad Campus,Islamabad,Pakistan.

Abstract Far infrared (FIR) radiation (3-100 μm) is an electromagnetic spectrum commonly studied for biological effects. This article aims to discuss using Far infrared radiation with sub-division (4-24 μm) of this waveband to stimulate tissues and cells and is considered an effective therapeutic modality for specific medical disorders. The IR application as a medical therapy has advanced rapidly in recent years. For example, IR therapy like IR-emitting apparel and materials that can be run solely by body heat (does not need an external power supply) have been developed. New methods for providing FIR radiation to the human body have emerged due to technological advancements. Specialty saunas and lamps that emit pure FIR radiation have become effective, safe, and widely used therapeutic sources. Fibers infused with thermide, FIR emitting ceramic nanomaterials and knitted into fabrics are used as clothes and apparel to produce FIR radiation and benefit from its effects. A deeper understanding of FIR's significant innovations and biological implications could aid in improving therapeutic efficacy or developing new methods that use FIR wavelengths.

Keywords: far-infrared radiation; FIR emitting ceramics and fibers; infrared sauna; radiant heat; far infrared for health; far infrared for wellness

Introduction

The electromagnetic radiation from the sun is a natural threat to all living things. It impacts living things at all levels, from subcellular organs to the entire body, positively and negatively. A portion of the electromagnetic spectrum called infrared radiation has been successfully employed for thousands of years to treat and alleviate a wide range of diseases and discomforts. One method—possibly the oldest—of delivering radiation in a controlled environment and at the perfect times for treatment—involves heated saunas. The advantages of far-infrared radiation (FIR) have grown as technology has advanced to deliver a purer version of FIR. Especially clothing and filaments of FIR emitting heat lamps are made of filaments(fibers) coated with FIR radiating nanoparticles that are currently employed to provide these thermal radiation effects. This research examines the potential efficacy of FIR as a therapeutic approach for a range of diseases [1].We discuss both conventional and innovative applications and the most recent developments in technology and academic research.

What is FIR radiation?

Electromagnetic radiation with wavelengths between 780 nm and 1000 m is known as infrared (IR). The International Commission on Illumination (CIE) divides infrared radiation into three bands:near-infrared, mid-infrared, and far-infrared. It shows in Table 1[2].

Studies have shown that FIR improves skin wound healing, relieves stiffness, pain, fatigue, and photo prevention associated with ankylosing spondylitis, rheumatoid arthritis, treats psychiatric,neurological, and ophthalmic disorders, and stimulates photodynamic therapy and the proliferation of cardiac and mesenchymal stem cells[3].

How does FIR affect the physiology of the body?

The use of FIR in medicine necessitates understanding how FIR electromagnetic radiation interacts with biological structures (such as cell membranes, cells, cell fluids, especially DNA/proteins, water, fat,and living systems as a whole). The fundamental biophysical mechanisms of electromagnetic radiation's interaction with live cells can be described at the cellular level in terms of changing mitochondrial metabolism and cell membrane potentials [4]. In molecules, vibrational states of the bonds absorb FIR energy(photons). Dominant factors in biological solutions are high water concentration in biological systems, the dielectric characteristics of water,the interaction of water molecules with ions,and the significant dipole moment that this effect produces.

In addition to the water molecules associated with the electromagnetic field and its effects, consideration must be given to the "mesostructure" impact in living systems, where proteins and charged groups (placed at specific locations on the proteins) are essential to the overall biological processes. The association of these precisely positioned charged groups with the water molecules influences the dielectric behavior of the entire molecular assembly,affecting how well it functions biologically. Because of this, the water content in tissues (even at the cellular level) effects and changes their dielectric characteristics. Additionally, the relaxation of these molecular "mesostructures" can exhibit variations frequently. These factors make the presence of water essential to the action between FIR and living things[5].

FIR use in medical field

The terms "biogenetic radiation" and "biogenetic rays" have been coined and widely applied in the current literature to describe FIR as a therapeutic modality. FIR wavelengths are too long for the eyes to see,but the body perceives them as gentle thermal radiation that can reach depths up to 1.5 inches below the skin. This energy is adequate to resonate with natural frequencies and generate vibrational and rotational motion in the bonds composed primarily of water molecules. The epidermal temperature that results from FIR radiation on the skin is higher than it would be with a similar heat load from shorter wavelengths. The extended erythemal reaction brought on by FIR exposure has been thought to be caused by elevated epidermal temperatures; however, at this level, FIR does not result in visible skin heating and can therefore have limited unwanted biological effects if there is noexternal power source [6].

How does FIR affect the molecular and cellular levels?

Despite all these various medical applications for FIR, our understanding of the actual mechanisms underlying its biological impacts and hyperthermic outcomes is still lacking. There are two different types of FIR therapies. The first type (FIR generators or saunas, some run on electricity) are adequate to heat the tissue,whereas another type (no external power but depends on body energy or natural ambient energy in the environment), such as thermide,specialized ceramic discs, powders, and fabrics, have such low irradiances that they do not dramiatically heat the tissue[7].

FIR therapy is divided into two types, heating, and non-heating.Although it has been noted that heating FIR treatment increases the flow of blood, this effect may be a result of improved thermoregulation, which happens when tissue is heated. However, the rise in blood flow is likely noticed with non-heating FIR therapy due to vasodilation by releasing NO from CCO storage facilities[8].

Furthermore, NO is bound to myoglobin and hemoglobin [9]. In the case of a non-heating system, there is "concentrated water," tiny water layers that accumulate on hydrophobic surfaces like cellular membranes that provide heat to tissues [10]. It is conceivable that highly modest quantities of vibrational energy given by non-heating FIR could alter the membrane's structure beneath the nanoscopic water layer without causing bulk heating. Even little changes in the membrane's structure could significantly impact a cell if the membrane has an ion channel. All cell membranes have ion channels,which come in several varieties for both cations and anions [11];nevertheless, mitochondrial membranes contain the most significant number of ion channels [12], particularly calcium channels [13] that could be opened by non-heating FIR, hence enhancing mitochondrial respiration.

It must be noted, the explanation above is still speculative at this time,but it is unquestionably a testable hypothesis with a great deal of scholarly evidence. One can wonder whether cells exposed to non-heating FIR can experience effects on their mitochondria, such as increased adenosine 5′-triphosphate (ATP) production, NO, oxygen consumption, reactive oxygen species (ROS) production, and changes in matrix metalloproteinase(MMP) and calcium levels.

How is FIR radiation delivered?

We discovered three primary methods for delivering therapeutic FIR radiation after studying the peer-reviewed applications of such systems: i) infrared heating lamps; ii) infrared emitting fabrics and ceramics, and iii) infrared saunas and waon therapy.

FIR heat lamps

Infrared heat lamps deliver FIR as a therapeutic intervention, emitting varying amounts of FIR. Unfortunately, "pure" FIR emitting lamps are costly, so lamps are used that emit “mixed" emissions, i.e., emitting in shorter wavelength. A common type of specific infrared heat lamp emits radiation ranging from 2 to 25 μm. These infrared ray devices are primarily used for the treatment of rhinitis. Hu and Li reported that the symptoms like nasal and eye itching, rhinorrhea, sneezing,and nasal stuffiness were all drastically improved with FIR therapy[14]. The last treatment improved the smell impairment. To treat vascular access dysfunction in hemodialysis (HD) patients with an insufficient access flow (Qa), Lin [15] employed an FIR emitter. This randomized trial showed that FIR therapy could enhance the native arteriovenous fistula (AVF)'s access flow and potency. After a trail running race, researchers demonstrated that FIR therapy decreased athletes'exercise-induced muscle injury symptoms[16].

FIR emitting fabrics and ceramics

Ceramics that emit FIR have long been known [17]. Depending on their temperature, all-ceramic materials can emit infrared radiation.In the days of gas lighting, gas flames were used to heat ceramic mantles to produce visible radiation, and FIR depends on the temperature obtained. The association between IR radiation intensity and temperature is controlled by the precise chemical makeup of the ceramic material. Wien's displacement law demonstrates that the wavelength range is also purely temperature-dependent [18].

When the boron-silicate mineral tourmaline milled into fine powders emits FIR [19], the qualities of the FIR emission vary on particle size. Different products of Tourmaline powder have been applied to the skin to influence blood flow[20].Similarly,thermide or FIR emitting ceramics discs have been affixed to the skin to produce a beneficial effect. Fabrics are woven with the fibers embedded with the FIR-emitting small particles of ceramic material. Different garments can be made with these fabrics worn on various body parts.

It is necessary to look at the thermodynamics of the process when FIR emitting materials or fabrics are employed as therapeutic devices.Energy can be produced or destroyed. Radiation, convection, and conduction are the three ways that heat (molecular vibrational energy) can transfer between two objects. The fact that the human body is much hotter than the surrounding air indicates that it is the primary source of energy needed to fuel the FIR emission from the apparel. These ceramic particles serve as "ideal absorbers," maintain a high enough temperature, and then emit FIR back to the body. As a result, energy from the human body is transferred to them. Although this appears to be an energy-neutral process that cancels itself out, it is not because the FIR emitting material prevents the loss of FIR that would otherwise have escaped through normal clothing. The same effect could have been achieved with an FIR reflective foil suit or something similar. The balance of conduction and convection will be determined by how close the garment is to the skin. Transfer of FIR between body and tightly fitted cloth is through conduction whereas,in case of loose fitted garments convection is required to transfer FIR because it is heating up a layer of air between the skin and the garment.

Discs made from FIR emitting material were put to the women’s breasts who had trouble during lactation with not having enough milk[21], and this improved lactation problems. Same as blanket made of FIR emitting discs has been found to improve sleep quality [22].Raynaud's syndrome and hand arthritis have both been successfully treated using gloves constructed from FIR emitting materials [23].Weight loss has been accomplished using belts comprised of these materials. Conrado and Munin did an investigation on wearing a clothing composed of synthetic fibres with powdered ceramic will result in lower body measurements[24]. The data revealed a decrease in body circumference, which could be attributed to an increase in peripheral blood flow and microcirculation, and these variations could help better overall health.

A belt embedded with FIR-emitting sericite mineral was used to examine the relief of menstrual pain [25]. Ceramics were heated by Hot packs and ensured minor pain relief. However, the dysmenorrhea severity reduced during the treatment period. FIR belts were utilised to reduce pain and discomfort while also raising localised surface body temperature and abdominal blood flow [26].

Rao et al.used bioceramic-coated neoprene garments with a"topical cream" to treat leg cellulite. Each patient was randomly assigned to either the left or right leg for occlusion by the garment, and control was with the contralateral side serving with no occlusion [27]. The studies reported an overall improvement in cellulite. The occlusion of a bioceramic-coated neoprene garment enhanced the topical agent's effect on cellulite reduction [28].

Celliant? is a polyethylene terephthalate (PET) fiber that contains ceramic nanoparticles that emit infrared light. York and Gordon investigated the use of this fiber socks in chronic foot pain patients caused by diabetic neuropathy or other disorders [29].It reduced pain more in non-neuropathic patients than in neuropathic subjects.

Infrared saunas and waon therapy

The temperature of the heating elements in these cabins is typically between 300 and 400 degrees Celsius, and the emission is in the FIR range, suggesting that the heat exchange between the body and the environment is primarily radiative (radiant heating), with cabin air temperatures of 40 degrees celsius or less. FIR warming chambers can heat the skin more quickly than conventional saunas, but more skin must be exposed to the light for there to be any noticeable sweating.FIR sauna therapy has been demonstrated to enhance cardiac and vascular function in individuals with chronic heart failure and lessen oxidative stress [30]. Beever investigated how FIR saunas improved the quality of life for type II diabetic patients [31]. A study of patients with rheumatoid arthritis and ankylosing spondylitis found that infrared sauna therapy reduced stiffness, pain, and fatigue[32].

Waon therapy involves placing the body in an IR chamber set at 60°C for 15 minutes, wrapping it with thermal blankets and laying down to maintain temperature for another 40 minutes, and then giving the patient water to replace moisture lost through perspiration. In Japan,these chambers are common [33]. In Japan [34] and Korea [35],waon treatment has been utilised extensively for cardiovascular diseases, particularly peripheral arterial disease and chronic heart failure [36]. It aids in rehabilitation and can improve heart function[37]. In the treatment of chronic obstructive pulmonary disease, waon therapy has an adjuvant impact[38].

Emerging field of studies of Infrared Therapy

Neural stimulation

It has a higher spatial resolution because there is no electrochemical link between the resource and the target tissue with infrared neural stimulation (INS). Additionally, FIR radiant discharge can be precisely tuned to show the incoming traffic. On the other hand, the potential drawbacks of INS include the possibility of tissue damage due to heat from excessive energy and the restricted penetration of stimulation that depends on the IR absorption characteristics of tissue[39].

One potential method of INS is photothermal effects resulting from energy absorption by water as opposed to photochemical process that can happen with radiation having higher photon energy (relatively short wavelength) or energy pressure waves [40]. One putative receptor that might be triggered by INS is the"transient receptor".

Transient receptor potential vanilloid 1 (TRPV1), a heat-sensitive ion channel. When radiant energy is absorbed by water in brain tissue,TRPV1 may be thermally activated [41].

In their assessment of INS applications from 2016, Ken Zhao et al.centred on the technology's capacity to stimulate diverse neuronal types, such as the facial nerve, cochlea, vestibular system, and cortex,using optical radiation. According to their findings, water absorbed most FIR radiation [42].

FIR effects on skin:photoaging vs.photorejuvenation

Since IR radiation from the environment is constantly coming into contact with human skin, this energy may either directly or indirectly induce the formation of ROS or free radicals. Numerous studies have discovered that a small outburst of IR-stimulated ROS may be advantageous for photorejuvenation. The use of FIR radiation on wound healing of rat thick skin has demonstrated an improvement in the formation of anti-inflammatory cytokine (TGF-1), the growth factor and which activates fibroblasts for enhanced wound healing.FIR radiation has also been utilised to directly promote fibroblast proliferation, which boosted fibroblast propagation in vitro [43].

Antitumor action

Numerous investigations conducted over the last ten years have discovered that FIR radiation can cause damage to DNA in cancer cells[44]. Oxidative stress is connected to the suggested process. When ROS is produced by FIR's impact on the electron transport chain, at a low level, it accelerates signal transduction and at a high level, it directly damages cellular organelles. Human mitochondrial DNA(mtDNA) has been found to be damaged by FIR-induced mitochondrial ROS, altering the function of the respiratory chain[45].Additionally, mtDNA mutations are significant contributors to clinical disorders. In mtDNA, more than 100-point mutations have so far been identified [46]. These findings suggest that FIR radiation may be a successful treatment for different cancers by limiting the multiplication of cancer cells depending on a particular cell type.

Neural and adipose regeneration

The underlying mechanisms of IR brain stimulation is yet unknown.However it uses non-coherent or coherent light to modify a neurobiological function and treat traumatic brain injury or neurodegenerative disorders without causing a heating effect [47].

Discussion

According to a number of studies, water molecules have the ability to absorb light at mid-infrared (MIR) and FIR wavelengths. When the hydrophilic/hydrophobic balance is just right, radiant energy can produce an exclusion zone (EZ) at a water interface [48]. Up to 70 %of the power input can be released from EZ water's electrical charge store. A thin coating of water that accumulates on hydrophobic surfaces is a characteristic of cellular membranes [49]. Non-heating IR radiation in a very low amount may be able to disturb the structure of nearby molecules as well as that of the nanostructured water layers without having any discernible heating effect on the bulk of the system (i.e. without raising the temperature) [50]. Gradients in the intramitochondrial viscosity of water have been discovered using the nano-indentation method [51]. In reaction to the alteration of ROS levels brought on by non-thermal levels of FIR, ATP synthesis can either increase or decrease. This "mitochondrial nanomotor" might be controlled by the FIR, which could boost ATP production by thinning the interfacial water layers' viscosity. Recent research suggested that light water interactions might be used to trigger oxygen-independent and oxygen-dependent pathways [52]. Interfacial EZ-water is produced by IR as a carefully selected electrolytic recharge bio-battery as an end result of interactions between light, water, and energy processes [53]. Nucleotide-phosphates, such as ATP and GTP, are highly energetic molecules that are produced by light energy in oxygen-dependent pathways. In the oxygen-independent mechanism,interactions between water and light cause photoinduced nonlinear oscillations in water that deliver energy for cellular processes like signalling, metabolism, and gene transcription.

Conclusion

New methods for exposing the human body to FIR radiation have been made possible by technological breakthroughs. Pure FIR radiation from specialty lamps and saunas has become a popular, secure source for producing therapeutic benefits. Fabrics made from fibres infused with ceramic nanoparticles that emit FIR are used as clothing and wraps to produce FIR radiation and benefit from its effects on health.The use of IR therapy has advanced significantly in recent years,as the potential contribution of FIR to photoaging or photo rejuvenation.

Although there is clear and strong evidence, future uses for non-heating FIR could be dramatic if it can be demonstrated more clearly that there are universal and repeatable biological effects. In addition to being used as bandages and dressings for various medical illnesses and wounds that need to heal, IR emitting materials also hold great promise for applications that improve lives. It is possible to produce clothing for competitive sports and recreational activities that enhance performance. FIR emitting capabilities would increase the performance of cold weather clothing, while FIR-emitting mattresses and bedding would enhance sleeping environments. Studies on IR-emitting apparel or dressings have demonstrated that they can enhance blood flow and lessen weariness in soccer players. This type of implementation may be a new adaptable way of treating medical illnesses and implementing mobile, lifestyle-enhancing activities (such as outdoor activities, sleeping, and home care) than conventional IR light sources and saunas.