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EFFECTS AND APPLICATIONS OF CRYOEXPOSURE ASSOCIATED WITH
HIGH INTENSITY ELECTROMAGNETIC FIELD IN HEALTH AND AES-
THETICS: A REVIEW
Carlos Ruiz-Silva1
Daniela Moleiro2
Caroline R. Ruiz-Silva3
Abstract: Obesity has emerged as a global epidemic and represents a major risk factor for numerous
chronic diseases, such as type 2 diabetes, cardiovascular disease, and cancer. Although adopting a healthy
diet and regular exercise remain the cornerstones of weight management, recent research has revealed
that cold exposure and associated muscle contractions can substantially contribute to weight loss. This
article presents a comprehensive review of the physiological mechanisms that link cold exposure to
weight loss, with a particular focus on the induction of browning and irisin production through pulsed
electromagnetic eld (PEMF) muscle stimulation technology, which uses alternating magnetic elds
based on the law of electromagnetic induction to stimulate supramaximal muscle contractions with high
magnetic ux density. The growing concern and interest in physical tness, not only from an athletic
but also aesthetic point of view, has driven the search for new methods and technologies that can aid
in gaining muscle mass and tone. Recent studies have reported that 81% of respondents expressed
dissatisfaction with their body image, even though 56% had a normal body mass index. Pulsed
electromagnetic eld (PEMF) muscle stimulation technology employs alternating magnetic elds based
on the law of electromagnetic induction to induce supramaximal muscle contractions. PEMF generates
impulses independent of brain function and at a frequency that does not allow muscle relaxation, thus
characterizing tetanic contractions. Electrical currents and electromagnetism have long been used in
1 Graduate Program in Bioengineering – Universidade Brasil
2 CTA College
3 CTA College
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physical therapy and rehabilitation, primarily for muscle strengthening. However, PEMF technology has
emerged as a more effective and less invasive alternative for the patient, primarily intended for toning
and strengthening muscle groups. In this study, we performed a comprehensive review of all available
scientic articles indexed in PubMed and Web of Science over the past 20 years on this technology
and its effects on skeletal muscle. We discuss the scientic evidence available from clinical studies and
analyze the effects and possible mechanisms of action on muscle contraction.
Keywords: cryoexposure, electromagnetic eld, health, aesthetics
INTRODUCTION
Obesity is a signicant public health problem, with cardiovascular disease associated with
obesity causing 17 million deaths per year worldwide. In Brazil, 18.9% of adults are affected by obesity,
according to data from the Ministry of Health in 2017. The prevalence of obesity and overweight is
increasing, leading to subvisceral fat deposition, which is associated with an increased risk of several
life-threatening diseases, such as cardiovascular disease, diabetes, metabolic syndrome, and some
forms of cancer. Thus, weight loss through aesthetic treatments is essential to reduce the prevalence
of cardiovascular diseases. Non-invasive fat reduction is gaining popularity as a frequent non-invasive
cosmetic procedure in the United States, according to the Aesthetic Society. The reduction of adipose
tissue is energy-dependent and can be achieved by reducing fat stores (lipolysis) or by permanently
removing adipocytes.
Lipolysis is a metabolic process that breaks down the triglycerides present in fat cells into
their constituent molecules, glycerol and free fatty acids (FFA), through hydrolysis. Glycerol serves
as a carbon source for hepatic gluconeogenesis, whereas FFA are transported in the blood bound to
albumin and are oxidized or converted to ketone bodies in tissues through β-oxidation. The byproducts
of β-oxidation, ATP and NADH, promote gluconeogenesis. FFA is converted into ketone bodies in the
liver, which serves as an energy source for the brain, thereby reducing blood sugar consumption that
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has been depleted. The main enzymes involved in lipolysis are adipose triglyceride lipase (ATGL),
hormone-sensitive lipase (HSL), and monoglyceride lipase (MGL).
In addition to lipolysis, adipose tissue can be permanently eliminated through various
regulated cell death programs, such as pyroptosis, necroptosis, and apoptosis. Apoptosis is a complex
intracellular pathway that allows the body to control the number of cells and tissue size. The most
distinctive signs of apoptosis processes are cell shrinkage accompanied by nuclear alterations, such
as chromatin condensation (pycnosis) and nuclear fragmentation (karyolysis).
Recent research has uncovered new functions of adipose tissue, including its participation
in energy balance, where white adipocytes store energy while brown adipocytes dissipate it as heat.
Beige adipocytes have a exible phenotype and can store or dissipate energy according to physiological
circumstances. Adipose tissue also contributes to the production of pro-inammatory molecules,
such as cytokines, adipokines, and chemotactic factors, which are involved in the state of chronic
low-grade systemic inammation seen in obesity. Adipocytes play an active role in establishing
this inammatory state, either by producing inammatory mediators (adipokines) or by cell-to-cell
interaction with resident macrophages.
Adipokines, once considered only a passive tissue to store excess energy in the form of
triacylglycerols, are now known as bioactive substances expressed and secreted by adipocytes (SILVA
et al., 2020). Adipocytes are derived from mesenchymal stem cells and go through intermediate stages
from adipoblasts and pre-adipocytes expressing transcription factors 21 and MyF5/BMP7 to white
and brown adipocytes, respectively.
The muscular system also plays a crucial role in achieving a harmonious and aesthetically
pleasing body contour. Muscle toning can be accomplished through physical activity (Gentil, 2017)
or through high-intensity focused electromagnetic eld (HIFEM) procedures (Kent, 2019; Kinney,
2019; 2020; Halaas, 2020). Intense muscle contractions require a signicant amount of energy, which
is delivered in the form of FFA from adipose tissue via lipolysis. This process not only activates beta
oxidation but also leads to overall reduction of triglycerides and increased activity of the enzymes
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malate dehydrogenase, succinate dehydrogenase, and beta oxidation enzymes of NADH (Goldberg,
2021).
ADIPOSE TISSUE
Adipose tissue is a complex and dynamic organ composed of adipocytes, which are specialized
cells that store and release lipids. These cells are highly regulated by a multitude of hormonal and
environmental factors. Adipose tissue can be classied into two distinct types based on its color and
function: brown adipose tissue (BAT) and white adipose tissue (WAT). Brown adipocytes contain
numerous mitochondria and are highly innervated and vascularized, which makes them capable of
generating heat through the uncoupling of oxidative phosphorylation. In contrast, white adipocytes
are less metabolically active and primarily serve as a storage site for excess energy. The relative
proportion of BAT and WAT in adipose tissue varies depending on age, diet, and ambient temperature,
among other factors. In addition, adipose tissue is an important endocrine organ that secretes a variety
of bioactive substances, including adipokines, which can inuence metabolism, inammation, and
cardiovascular health. Therefore, the proper functioning of adipose tissue is crucial for maintaining
metabolic homeostasis and overall health.
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White adipocytes, which are the main energy storage site in the body, have a unique cellular
structure that reects their specialized functions. Adipocytes are characterized by a single, large
drop of lipid that occupies most of the cell volume. This structure allows for efcient lipid storage
and mobilization in response to energy needs. In contrast to brown adipocytes, which have abundant
mitochondria and high metabolic activity, white adipocytes have poorly developed organelles and
relatively low metabolic activity. In addition, the nucleus is displaced to the periphery of the cell and
the cytoplasm forms a thin border, which facilitates the secretion of adipokines and other signaling
molecules. The small, elongated mitochondria in white adipocytes have short, randomly arranged
ridges, which reects their relatively low oxidative capacity. Despite their apparent simplicity, white
adipocytes play a crucial role in metabolic homeostasis, and their dysfunction is implicated in the
pathogenesis of several metabolic disorders, including obesity and type 2 diabetes.
In addition to its thermogenic function, brown adipose tissue (BAT) also plays a role in
glucose and lipid metabolism. BAT has a high rate of glucose uptake and is able to utilize glucose
as a fuel source for thermogenesis. In addition, BAT activation has been shown to increase insulin
sensitivity and decrease plasma triglyceride levels. This is due to BAT’s ability to absorb and store
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lipids, reducing the amount of circulating lipids that can contribute to metabolic disorders. In addition,
recent studies have suggested that BAT-derived factors such as adiponectin and broblast growth factor
21 (FGF21) may act as endocrine signals to regulate systemic metabolism and insulin sensitivity in
other tissues, highlighting the complex interaction between adipose tissue and the endocrine system.
Adipose tissue is a complex organ composed of different types of cells with distinct
morphologies, functions, and developmental origins. White adipocytes serve as energy storage sites,
storing lipids, which are later released during fasting or increased energy demands. These cells have a
spherical lipid drop that maximizes volume and minimizes the space occupied, and their cytoplasmic
organelles, especially mitochondria, are poorly developed. On the other hand, brown adipocytes are
smaller and contain numerous lipid droplets and large mitochondria with abundant uncoupling protein
1 (UCP1). These multilocular cells produce heat through the oxidation of fatty acids to meet the body’s
energy needs in response to cold temperatures or other stimuli. The recent discovery of paucilocular
or beige adipocytes with an intermediate morphology between white and brown adipocytes provides
new insight into the plasticity of adipose tissue and its ability to adapt to different environmental and
physiological stimuli. These cells have the potential to transdifferentiate into brown adipocytes when
exposed to certain stimuli, such as chronic colds or pharmacological agents, leading to the development
of “dark” adipose tissue. Activation of brown adipose tissue is mediated by the sympathetic nervous
system, which increases the level of cyclic adenosine monophosphate and activates lipolysis to
provide fuel for thermogenesis. The molecular mechanisms underlying thermogenesis in brown and
beige adipocytes involve the unique property of mitochondrial uncoupling, which separates electron
transport from ATP synthesis and generates heat instead of ATP.
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Human brown adipocytes possess molecular attributes such as constitutive UCP1 expression,
homogeneous multilocular morphology, and myogenic origin (Myf5+), while beige adipose tissue arises
from non-myogenic progenitors (Myf52) under environmental stimuli such as cold and exercise, and
exhibit low levels of UCP1 expression under unstimulated conditions (Okla, 2017). Studies conducted
by Dr. Lee in 2013-2016 demonstrated that exposure to cold and exercise increases levels of the
hormone irisin (produced by muscle) and FGF21 (produced by brown fat), and that in the laboratory,
irisin and FGF21 can differentiate cells into beige adipose tissue cells over a six-day period (Loap,
2018). These two hormones, irisin and FGF21, are the main signals to stimulate energy expenditure in
the laboratory. Recent research suggests that there is an inverse association between BMI and plasma
irisin concentrations in morbidly obese individuals. In mammals, UCP1 BAT provides the primary
mechanism for shiver-free adaptive thermogenesis to defend body temperature in cold environments
and for transcriptional activation of UCP1, several transcription and co-regulatory factors, including
PPARs, PGC1α, are required (Dempersmier, 2015; Kelpert, 2017). However, the temperature range
used to assess cold-induced thermogenesis represents another source of variability. The concept of
cryoexposure is the use of local tissue cooling to control obesity. In cryolipolysis, apoptosis (hypoxia
and reperfusions) is observed with loss recorded for a long period (Avram, 2009; Coleman, 2009;
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González, 2019; Jaliman, 2013; Manstein, 2008; 2009; Nelson, 2015; Pugliese, 2020; Zelickson, 2009).
Cryoexposure is a controlled method that uses cooling to induce lipolysis without an inammatory
process (controlled by biochemical tests), a result generated by adaptive cryothermygenesis (Loap,
2018; 2022; Pinto H, 2012; Rauen, 1999, 2000; Velrand, 1999). Exposure to environmental cold leads
to a decrease in adipose tissue.
When exposed to cold temperatures, homeothermic mechanisms in humans include increased
vasoconstriction of the skin to reduce heat loss and an increase in endogenous heat production, which
is triggered by an increase in basal metabolic rate. Exposure to cold also causes skeletal muscles to
produce heat through muscle shivering-dependent thermogenesis, while muscle shivering-independent
thermogenesis occurs in brown adipose tissue (BAT). Although the hypothesis of using cold exposure
as a weight loss strategy was abandoned due to the belief that humans lacked brown adipose tissue,
studies have since shown that humans possess signicant amounts of brown fat deposits, and the
browning process can be stimulated by β3-AR receptor agonists. (Ikeda, 2020; Lee, 2013).
The physiological response of brown adipose tissue (BAT) to cold stimulation during physical
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activity or cold exposure induces a greater thermogenic response, characterized by an increase in
uncoupling protein 1 (UCP1) expression and uncoupled respiration relative to canonical brown cells
(DEMPERSMIER, 2015). The differentiation process of BAT is driven by specic transcription factors
such as peroxisome proliferator-activated receptor (PPAR) when activated by non-inammatories,
Zinc Finger Protein 516 (ZFP516), and CCAAT/beta binding protein.
Loap’s recent publication brought to light the concept of weight loss with cryoexposure, based
on the hypothesis of transformation of white fat into brown tissue that dates back more than a century
(Loap, 2018). The use of cold exposure increases energy and caloric expenditure via thermogenesis
and fat metabolism (Loap, 2018). Despite previous beliefs that brown adipose tissue was absent in
humans, uorodeoxyglucose imaging showed the presence of large expanses of brown fat deposits
(Loap, 2018). Evidence suggests that the conversion of white tissue to brown tissue is possible through
the activation of BAT genes by transcription factors (Dempersmier, 2015).
Daily serial cooling of abdominal adipose tissue results in a progressive loss of adipose
tissue, conrmed by dual-energy X-ray absorptiometry, with no evidence of systemic inammation,
abnormal fat mobilization, or disruption of cellular integrity and necrosis of death (Loap, 2018).
Cryoexposure has been shown to reduce circumference and BMI without affecting inammatory
biomarkers, enabling daily applications (Loap, 2018). Lipid prole markers, including total cholesterol
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(TC), high-density lipoprotein (HDL), alanine aminotransferase (ALAT), alkaline phosphatase (ALP),
aspartate aminotransferase (AST), gamma glutamyltransferase (GGT), triglycerides (TG), and their
relevant ratios, as well as thyroid hormone (TSH, total T4, and free T4), were also analyzed (Loap,
2018).
Each application of cryoexposure results in the extraction of 1330 Kcal via thermogenesis, as
reported by Yoneshiro, Lans, and Le in 2013 (Loap, 2018). Cold-induced upregulation of UCP-1 factors
ZFP 516 in low-temperature fat cells generates thermogenesis, allowing mitochondria to metabolize
fat via beta-oxidation and generate heat (Dempersmier, 2015). Exposure to cold also increases the
expression of metabolic activity in beige tissue, leading to increased expression of the UCP-1 protein,
which promotes thermogenesis and heat generation (Ikeda, 2020).
The key to maximizing the effects of cryoexposure is to freeze as many areas as possible
simultaneously and stimulate sympathetic nervous system receptors through electrolipolysis or
electrostimulation to induce Zfp516 expression through cold, sympathetic stimulation (contraction).
Zfp516 binds to the promoter regions PGC1a and Cox, promoting transcriptional activation
(Dempersmier, 2015). Intense contractions increase the expression of signaling proteins, such as
PPAR PGC-1 alpha, which regulates mitochondrial biogenesis. Supramaximal contractions above
10 Hz and high magnetic ux density are the most effective at activating PGC1-alpha and inducing
dimming. These contractions stimulate the anaerobic muscle bers to undergo repetitive contractions,
leading to a high energy demand and a subsequent shift from aerobic to anaerobic metabolism.
Peroxisome proliferator-activated gamma-1 receptor alpha (PGC1-alpha) is a transcriptional
coactivator that plays a critical role in the regulation of energy metabolism and thermogenesis. One
of its main functions is to induce the browning of white adipose tissue (WAT) by promoting the
conversion of white adipocytes into brown adipocytes. This transformation involves the activation of
uncoupling protein 1 (UCP1)-mediated thermogenesis, which generates heat and increases metabolic
activity in brown adipocytes.
Several physiological factors, such as temperature and exercise, have been shown to regulate
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the browning process. High-intensity supramaximal contractions, a type of muscle contraction that
involves rapid and repetitive stimulation of muscle bers, have been shown to activate PGC1-alpha,
leading to increased mitochondrial biogenesis and oxidative metabolism. PGC1-alpha activation occurs
through two mechanisms: rst, supramaximal contractions cause a rapid and sustained increase in
intracellular calcium levels, which activates calcium-dependent calmodulin kinase (CaMK); CaMK,
in turn, phosphorylates PGC1-alpha. Second, supramaximal contractions promote the release of
lactate and other metabolic intermediates that can activate AMP-activated protein kinase (AMPK), a
key regulator of energy homeostasis that also activates PGC1-alpha.
Interestingly, performing high-intensity supramaximal contractions in environments with
temperatures close to 0°C has been shown to be more effective in inducing dimming compared to
performing these contractions at room temperature. This is because exposure to cold can activate the
sympathetic nervous system and increase the secretion of norepinephrine, a hormone that stimulates
lipolysis and activates mitochondrial thermogenesis through the activation of β3-adrenergic receptors.
Activation of β3-adrenergic receptors leads to activation of AMPK, which in turn phosphorylates
and activates PGC1-alpha. PGC1-alpha induces the expression of genes involved in mitochondrial
biogenesis and oxidative metabolism, leading to an increase in mitochondrial thermogenesis and
energy expenditure.
In addition to its effects on thermogenesis, cold exposure can also activate the transient
receptor potential of the cationic channel member V subfamily 1 (TRPV1), which is sensitive to cold
temperatures and is expressed in sensory neurons and adipose tissue. Activation of TRPV1 leads to
the secretion of neuropeptide Y (NPY) and agouti-related protein (AgRP), two neuropeptides that
stimulate food intake and reduce energy expenditure. However, activation of TRPV1 in adipose tissue
can also lead to activation of mitochondrial thermogenesis through activation of sympathetic nerves
and norepinephrine secretion.
In summary, the performance of sub- and supramaximal contractions, with high magnetic
ux density, in environments with temperatures close to 0°C, is more efcient in inducing browning
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than at room temperature, due to the activation of the sympathetic nervous system and an increase in
norepinephrine strength, which promotes the activation of MTD thermogenesis through the activation
of β3-adrenergic receptors and the activation of PGC-1α. In addition, an exposure to cold can also
activate the cation channel of subfamily V member 1 receptor transient potential (TRPV1), leading to
the cause of neuropeptides that stimulated food intake and produced energy expenditure. However,
activation of TRPV1 in adipose tissue can also lead to activation of MTD thermogenesis through
activation of sympathetic nerves and inhibition of norepinephrine.
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