Role of physical therapy in irritable bowel syndrome: Current strategies and prospective options

Abstract

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by dysregulation of the gut-brain interaction. It has a high global prevalence, significantly impairs quality of life, and imposes a substantial socioeconomic burden. The pathophysiology of IBS is complex and not yet fully elucidated, with its heterogeneity reflecting the interplay of multiple factors, including abnormal gastrointestinal motility, visceral hypersensitivity, gut microbiota dysbiosis, low-grade inflammation, and central nervous system dysfunction. This mechanistic complexity not only accounts for the highly individualized symptom profile of IBS but also highlights the limitations of monotherapy in addressing the long-term management needs of patients. Given the limited efficacy, frequent adverse effects, and insufficient adaptability of pharmacological treatments to the heterogeneity of IBS, non-pharmacological interventions have increasingly attracted attention. Among these, physical therapies - using electrical, magnetic, thermal, photic, or mechanical stimulation - can modulate neural activity at central, peripheral, and autonomic levels and have shown promising potential in alleviating IBS symptoms. The underlying mechanisms of physical therapies for IBS are proposed to involve neural modulation, visceral sensory regulation, immunoinflammatory control, and optimization of gut-brain axis function, representing a multi-system, synergistic mode of action. This narrative review synthesizes and contextualizes recent advances in emerging physical therapies for IBS, with a focus on clinical efficacy, safety, and feasibility, while discussing their potential mechanisms within a unified theoretical framework. The current limitations of the evidence, including small sample sizes, inconsistent intervention parameters, and insufficient mechanistic validation, are also addressed. Finally, future research directions are proposed, encompassing mechanism-driven clinical studies, standardization of intervention parameters, and high-quality randomized controlled trials. Overall, physical therapy offers a non-pharmacological, multi-mechanistic intervention capable of modulating multiple physiological systems.

Key Words: Irritable bowel syndrome; Physical therapy; Non-pharmacological treatment; Exercise therapy; Acupuncture

Core Tip: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by impaired brain-gut communication, visceral hypersensitivity, immune activation, and autonomic imbalance. Physical therapies - including electrical stimulation, acupuncture, and mechanotherapy - have shown potential in modulating these interconnected pathways. This review discusses the neuromodulatory and anti-inflammatory mechanisms underlying physical therapy, highlighting its capacity to reduce abdominal pain, normalize bowel motility, and restore gut-brain homeostasis. By concurrently targeting multiple physiological systems, physical therapy represents a multi-mechanistic, non-pharmacological approach for IBS, offering new strategies for symptom management and improving patients’ quality of life.

INTRODUCTION

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder characterized by chronic or recurrent abdominal pain accompanied by altered bowel habits[1]. It affects approximately 10%-15% of the global population, substantially reducing quality of life, increasing healthcare utilization, and imposing a considerable socioeconomic burden[2-4]. Studies have shown that annual direct healthcare costs for IBS patients vary widely by country, ranging from €262 in Norway to $7547 in the United States; quarterly direct costs may reach €802, with mental health-related expenditures accounting for approximately 20%[4]. Moreover, patients report a willingness to trade an average of 10-15 years of life expectancy for immediate symptom resolution, and 15%-43% seek additional treatments or adjunctive products at their own expense[5], further highlighting the substantial disease burden.

Based on bowel movement patterns, IBS is classified into constipation-predominant (IBS-C), diarrhea-predominant (IBS-D), mixed (IBS-M), and unclassified (IBS-U) subtypes, with this heterogeneity further complicating diagnosis and individualized treatment[6,7]. Current IBS pharmacotherapy is largely subtype-directed, with rifaximin and eluxadoline available for IBS-D and secretagogues such as linaclotide and lubiprostone indicated for IBS-C. In contrast, effective pharmacological options for IBS-M and IBS-U remain lacking. Most current drugs offer only partial symptom control and are constrained by safety concerns or limited patient eligibility. Rifaximin primarily improves bloating, with modest effects on abdominal pain. Alosetron is restricted to refractory female patients with IBS-D due to risks of severe constipation and ischemic colitis[8-11]. These challenges highlight the urgent need for safer, sustainable, and mechanism-based therapeutic alternatives.

The pathophysiology of IBS is multifactorial, involving visceral hypersensitivity, motility disturbances, dysregulation of the brain-gut axis, autonomic nervous system dysfunction, low-grade inflammation, and psychological stress[12]. The multifactorial nature of IBS limits the effectiveness of single-agent pharmacotherapy, contributing to a growing interest in non-pharmacological approaches driven by perceived naturalness and safety. Physical therapies may offer therapeutic advantages by acting across peripheral and central pathways[13-16]. This review integrates current mechanistic and clinical evidence on physical therapies for IBS, including transcutaneous electrical nerve stimulation (TENS), vagus nerve stimulation (VNS), phototherapy, hydrotherapy, and other modalities. It summarizes their mechanisms, efficacy, and safety and outlines future research priorities to support clinicians and researchers seeking evidence-based, multimodal IBS-management strategies.

BRAIN-GUT AXIS AND THE PATHOPHYSIOLOGY OF IBS

IBS exhibits a highly complex pathophysiology involving interconnected sensory, motor, immune, neuroendocrine, and psychological pathways[17,18]. This complexity contributes to heterogeneity in clinical presentation and variability in treatment outcomes. Visceral hypersensitivity and gastrointestinal dysmotility - core features of IBS - often arise from aberrant peripheral sensory signaling and impaired brain-gut axis regulation[19]. Concurrently, autonomic dysregulation and hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis are particularly evident in stress-sensitive patients[20]. Immune abnormalities, including low-grade mucosal inflammation, further aggravate symptoms, while gut microbiota dysbiosis influences immune and neural signaling to exacerbate symptom severity[21]. Psychosocial stress amplifies central pain processing and heightens symptom perception by activating key central nervous system regions such as the anterior cingulate cortex (ACC) and amygdala[22]. Additional contributors - including disrupted bile acid metabolism and diet-related factors - further expand the mechanistic complexity of IBS[23,24]. Given the multi-target and multi-pathway nature of IBS, physical therapies may serve as complementary or alternative interventions. For example, TENS may restore autonomic balance and reduce HPA axis-mediated stress responses[25]; manual therapies and electroacupuncture (EA) can modulate visceral nociception, improve gastrointestinal motility, and attenuate inflammation[26,27]; and transcranial magnetic stimulation (TMS) may alleviate anxiety and depressive symptoms through central neuromodulatory effects[28]. The alignment between IBS pathophysiology and the mechanisms of action of these modalities has prompted investigation into individualized, precision-based physical therapy strategies in IBS management.

CURRENT THERAPIES

VNS

VNS, a novel neuromodulatory technique, has gained increasing attention for managing IBS and other disorders of the gut-brain interaction. VNS includes invasive and non-invasive approaches[29]. Non-invasive methods - such as transcutaneous auricular VNS (taVNS) and transcutaneous cervical VNS - are particularly attractive for clinical research due to their favorable safety profiles and improved patient acceptability.

Mechanistically, VNS delivers afferent signals to the central nervous system to modulate visceral nociception[30], while efferent activation triggers the cholinergic anti-inflammatory reflex, suppressing intestinal pro-inflammatory mediators and exerting analgesic and anti-inflammatory effects[31]. These properties support its potential application in subtypes such as IBS-C, which are characterized by abdominal pain and constipation.

Clinically, taVNS has demonstrated benefits in patients with IBS-C, improving quality of life, reducing abdominal pain, and increasing spontaneous bowel movements[15,32]. A multicenter, randomized, sham-controlled trial (n = 115) evaluated a taVNS device (IB-STIM; NeurAxis, Inc., Carmel, IN, United States) in adolescents with functional abdominal pain-associated IBS. After 3 weeks of treatment, 81% of patients reported overall symptom improvement, compared with 26% in the control group[33]. The device has been approved by the United States Food and Drug Administration for adolescent use, and its therapeutic effects may involve modulation of gut microbiota[34], suggesting relevance for brain-gut-microbiota axis regulation. However, its application in adult IBS populations remains unexplored. Reported adverse effects - such as ear discomfort, adhesive skin reactions, and occasional syncope - underscore the need for further research to establish long-term safety and efficacy across diverse patient groups.

TENS

TENS is a non-invasive peripheral neuromodulation technique whose analgesic effects primarily depend on modulating central nociceptive transmission. Noxious peripheral inputs evoke pain by releasing excitatory neurotransmitters and activating second-order nociceptive neurons within the central nervous system. By stimulating large-diameter, non-nociceptive afferents, TENS promotes the release of inhibitory neurotransmitters and suppresses the activity of central nociceptive transmission neurons, thereby achieving analgesia[35,36]. In addition, accumulating evidence indicates that TENS can alleviate visceral hypersensitivity and anxiety symptoms commonly observed in IBS by regulating visceral afferent signaling, modulating HPA axis activity, and normalizing gastrointestinal myoelectric rhythms[37-40]. Together, these multi-level neuromodulatory actions provide the physiological foundation for applying TENS in IBS management.

In studies involving patients with IBS-D, TENS combined with cutaneous acupoint stimulation has produced improvements in bowel habits and rectal sensory thresholds[41,42]. The acupoints selected in these protocols are predominantly localized within thoracolumbar sympathetic segments and their corresponding cutaneous projection zones. This spatial pattern suggests that the combined intervention may engage segmental autonomic regulation networks, offering anatomical and neurophysiological plausibility for its therapeutic effects.

Given the multi-pathway neuromodulatory properties of TENS, current research is increasingly exploring its integration with other physical modalities, such as photobiomodulation (PBM) or acupoint-based stimulation. Photobiomics refers to the systemic biological effects associated with PBM, particularly those involving cellular metabolism, mitochondrial function, and microbiome-related processes. In chronic neck pain, PBM combined with TENS has demonstrated superior analgesic effects compared with either modality alone[43]. A multi-arm randomized controlled trial involving 144 participants showed that PBM + TENS significantly increased pressure pain thresholds, reduced movement-evoked pain, and improved the global perceived effect. Similarly, studies on labor analgesia report that combined TENS and acupoint stimulation outperform single interventions in reducing visual analog scale pain scores and prolonging the time to pharmacological analgesia initiation, while simultaneously improving subjective childbirth experience (CEQ scores)[44]. These cross-condition findings provide valuable insights for IBS research, indicating that TENS may serve as a versatile platform for synergistic neuromodulation. Future studies should evaluate TENS in combination with PBM, acupoint stimulation, and other peripheral neuromodulation strategies across different IBS subtypes, with the aim of achieving comprehensive benefits in analgesia, anxiety reduction, gastrointestinal motility regulation, and overall quality-of-life enhancement.

TMS

TMS is a non-invasive brain neuromodulation technique that uses magnetic pulses to induce electrical currents in cortical neurons, thereby modulating neural excitability and the functional dynamics of distributed brain networks[45]. Common stimulation paradigms include single-pulse, paired-pulse, and repetitive TMS (rTMS), with rTMS being most widely utilized for pain and mood regulation[46-48]. Neuroimaging evidence demonstrates that TMS influences not only local cortical regions but also remote areas through network-level connectivity, particularly within functional circuits implicated in pain modulation.

The analgesic effects of rTMS primarily derive from targeted modulation of central pain regulatory systems[49]. For example, Algladi et al[50] reported that rTMS significantly reduced anorectal pain in IBS patients[51], highlighting its relevance for treating visceral hypersensitivity. IBS neuropathology involves dysregulation across multiple brain networks[52,53]. Among these, the dorsolateral prefrontal cortex (DLPFC) is a key target for the analgesic and anxiolytic effects of rTMS[54]. In IBS, right DLPFC activation increases during rectal distension and positively correlates with anxiety severity[55]. Given its established role in depression treatment, the DLPFC is central to modulating pain-emotion interactions, making it particularly suitable for IBS patients with comorbid affective symptoms[56].

Beyond the DLPFC, IBS patients exhibit functional abnormalities in the ACC, insula (a major pain-emotion integration hub), amygdala, and hippocampus (stress- and memory-related structures). Together, these regions compose a “visceral sensation-emotion processing circuit”[57-60]. However, the extent to which rTMS can modulate these nodes remains insufficiently characterized, leaving key questions regarding optimal stimulation targets and mechanistic pathways unanswered.

Despite their therapeutic promise, conventional TMS systems are bulky, energy-intensive, and poorly suited for everyday clinical or community-based use. Recent advances in battery-powered, wearable rTMS devices offer a potential solution, enabling high-frequency stimulation during free movement[14] and providing a low-burden option for chronic IBS patients, particularly those requiring long-term, home-based care. These developments may overcome longstanding limitations in accessibility and open new avenues for community-level neuromodulation. Overall, TMS represents a safe and precise method for modulating pain-emotion networks, with compelling potential to alleviate visceral hypersensitivity and comorbid affective disturbances in IBS. As device technologies evolve and mechanistic understanding deepens, TMS is poised to become an important component of multimodal IBS management, complementing peripheral neuromodulation techniques to enhance therapeutic efficacy and patient adherence.

Transcranial direct current stimulation

Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique that modulates cortical excitability and plasticity by delivering low-intensity electrical currents to the scalp[61]. Its efficacy depends on multiple parameters - including current waveform (direct, alternating, pulsed, or random noise), polarity (anodal or cathodal), intensity, and stimulation site[62]. The primary therapeutic mechanism involves promoting long-term synaptic plasticity, thereby modulating nociceptive networks within the brain-gut axis[63].

The ACC, a key hub integrating visceral sensory processing and emotional regulation, plays a central role in the development of visceral hypersensitivity in IBS. Current evidence indicates that the ACC is critically involved in the analgesic effects of tDCS[64]. Animal studies have demonstrated aberrant expression of synaptic plasticity-related molecules, such as GluN2B and GluR2, in the ACC under chronic visceral pain conditions, underscoring its involvement in central sensitization[65]. Targeting the ACC with tDCS may therefore modulate IBS-related pain pathways by reshaping synaptic plasticity within this region.

Patients with IBS frequently exhibit dysfunction within the prefrontal-limbic system, characterized by hypofunction of the DLPFC and hyperactivation of the amygdala. This dysregulated connectivity compromises top-down emotional control and heightens affective and nociceptive responses. Anodal tDCS over the left DLPFC can enhance cognitive regulation and suppress hyperexcitability in limbic regions such as the amygdala[66,67], thereby alleviating common IBS comorbidities, including anxiety and depression[68,69]. These effects parallel the established neuromodulatory pathways of tDCS in emotional disorders, offering a theoretical basis for integrating tDCS into multimodal IBS management.

Despite its therapeutic promise, translating tDCS into routine IBS care remains challenging. IBS is characterized by multifactorial pathophysiology involving brain-gut, immune, and microbiota interactions, and no consensus exists regarding a definitive central target. Additionally, considerable symptom heterogeneity limits the feasibility of standardized stimulation protocols. Mechanistic research also remains insufficient, with incomplete evidence linking stimulation targets to clinical outcomes. Future work should therefore prioritize: (1) Advancing foundational research on brain-gut axis mechanisms; (2) Developing individualized target identification and tailored intervention strategies for IBS subtypes; and (3) Establishing personalized stimulation-parameter optimization frameworks guided by neuroimaging, physiological metrics, and clinical phenotypes to support precision neuromodulation.

EA

Acupuncture, a core component of traditional Chinese medicine, exerts therapeutic effects by stimulating specific acupoints to harmonize qi and blood, regulate visceral function, and restore systemic balance[70]. EA, which applies electrical currents to enhance the intensity and duration of needle stimulation, represents a major step toward the modernization and quantification of acupuncture. Evidence indicates that EA activates multilevel neural pathways - including peripheral sensory nerves, the spinal dorsal horn, the brainstem, and higher-order centers such as the hypothalamus and prefrontal cortex - highlighting its substantial neuromodulatory potential[71]. Globally, acceptance of acupuncture continues to expand; more than half of World Health Organization member states (103/194) have incorporated acupuncture into national healthcare systems, and 29 countries, including the United States, Japan, and Canada, have established legal frameworks regulating its practice[72].

In the treatment of functional gastrointestinal disorders - particularly IBS - EA has demonstrated increasing promise in clinical and mechanistic research. Basic studies show that peripheral visceral sensory neurons and primary afferent nerves significantly attenuate peripheral sensitization under visceral hypersensitivity conditions[73]. EA also influences spinal and supraspinal structures, including the locus coeruleus-ACC and amygdala-insula circuits, suggesting broad efficacy in modulating central sensitization[74]. However, the analgesic mechanisms of EA remain heterogeneous, influenced by acupoint selection, electrical parameters, and treatment duration. At the molecular level, an integrated model of the relevant cellular pathways and biochemical mediators is still lacking. Clinically, several functional MRI studies have shown that EA at acupoints such as Tianshu (ST25) and Shangjuxu (ST37) modulates brain activity patterns in IBS patients, with subtype-specific neural responses. In IBS-C, voxel activation within the ACC, insular cortex, and prefrontal cortex decreases significantly, indicating modulation of nociceptive and emotion-regulating centers. In IBS-D, changes appear predominantly within the prefrontal cortex[75,76]. These subtype-dependent patterns provide neuroimaging evidence supporting precision EA interventions. Furthermore, randomized controlled trials suggest that EA and moxibustion can reduce colonic mucosal levels of pro-inflammatory and neuroactive substances, including substance P and vasoactive intestinal peptide[77], highlighting potential roles in modulating neuro-immune interactions and local inflammation. Future research should integrate multimodal neuroimaging (e.g., functional magnetic resonance imaging, diffusion tensor imaging), neuroelectrophysiology, and molecular approaches to elucidate the multilevel central-peripheral mechanisms of EA in IBS. Simultaneously, harmonizing traditional acupoint theory with contemporary neuroscience, standardizing EA parameters, clarifying mechanistic models, and advancing individualized treatment strategies will be essential for establishing a robust framework for precision EA therapy in IBS.

PBM

PBM is a non-invasive modality that uses low-level lasers or light-emitting diodes to activate intracellular photosensitive chromophores, such as cytochrome c oxidase, thereby modulating cellular function[78].

PBM reduces nociceptive signal transmission by suppressing Aδ and C-type nerve fiber activity, both of which are key contributors to visceral hypersensitivity[79-82].

Preclinical studies provide early support for the therapeutic potential of PBM in gastrointestinal disorders. In a rat model of IBS, PBM significantly attenuated visceral hypersensitivity[26]. Similarly, research in a canine model of diarrhea showed that PBM normalized bowel movement frequency and relieved diarrheal symptoms[83], expanding its applicability beyond functional pain to broader gastrointestinal dysregulation. Despite these promising findings, clinical evidence for PBM in IBS remains lacking.

Investigations of PBM in inflammatory bowel disease (IBD) offer important mechanistic insights relevant to IBS. PBM modulates pro-inflammatory cytokines [e.g., tumor necrosis factor-α, interleukin (IL)-1β, IL-6] and anti-inflammatory cytokines (e.g., IL-10), ameliorates histopathological alterations in colitis models, and reduces myeloperoxidase activity[84,85]. It further attenuates intestinal inflammation by regulating mast cell degranulation and shifting macrophage polarization from a pro-inflammatory M1 to an anti-inflammatory M2 phenotype[86]. Mechanistically, PBM interacts with the gut microbiome, inflammasome pathways, and the gut-brain axis, engaging multiple downstream signaling cascades to suppress local and systemic inflammation, thereby alleviating IBD-related fatigue, pain, and affective symptoms[87].

Notably, IBS is also characterized by low-grade mucosal inflammation, neuroimmune dysregulation, and comorbid anxiety and depression[53] - pathophysiological features closely aligned with PBM’s therapeutic targets in IBD. PBM has been proposed as a potential therapeutic approach for IBS, but its mechanisms and clinical efficacy remain to be rigorously evaluated.

Spa therapy

Spa therapy - encompassing balneotherapy, hydrotherapy, and mud therapy - is a core intervention in medical hydrology and physical medicine, with widespread clinical use supported by longstanding empirical observations[88]. Balneotherapy specifically comprises evidence-based treatments delivered in accredited spa centers using medically or legally recognized mineral waters, therapeutic muds, and natural gases, and forms an integral component of public health systems in several European countries[89]. Its primary physiological benefits derive from thermotherapeutic effects: Maintaining tissue temperatures between 38 °C and 42 °C activates systemic responses[90] that promote analgesia, reduce low-grade chronic inflammation, and modulate stress-related physiological states[91-95]. However, direct evidence for these anti-inflammatory and analgesic effects predominantly originates from research in chronic pain and inflammatory diseases. In the field of IBS, relevant clinical data remain limited, although emerging evidence supports its relevance for IBS-C. In a large Italian observational cohort (n = 3609), a 3-week course of mineral water supplementation (2000 mL/day) improved gastric acid secretion and significantly shortened intestinal transit time in IBS-C patients[96], suggesting that balneotherapy may exert clinically meaningful effects on gastrointestinal motility through targeted thermal mechanisms.

Moxibustion

Moxibustion is a traditional thermal therapy that stimulates specific acupoints through the combustion of herbal preparations containing dried mugwort leaves[97]. This process raises local skin temperature to approximately 43 ± 1 °C, activating transient receptor potential vanilloid 1 (TRPV1) channels implicated in visceral pain signaling. Afferent nerve transmission of these thermal stimuli to the spinal cord modulates dorsal horn neuronal excitability, thereby producing analgesic effects[98]. Basic research indicates that moxibustion alleviates IBS-related visceral hypersensitivity through coordinated actions across the central nervous system, spinal cord, and peripheral pathways[99-101]. However, most existing work originates from Asian countries, and standardized treatment guidelines or multicenter collaborations in Europe and North America remain limited. While several randomized controlled trials report significant improvements in IBS symptoms[16,98,102,103], the overall evidence base is constrained by small samples, methodological limitations, and inadequate biochemical outcome assessments. Robust, large-scale multicenter trials are needed to clarify its therapeutic efficacy and support the development of standardized clinical protocols.

Tuina

Tuina, a long-standing manual therapy widely used in traditional Chinese medicine, involves mechanical stimulation - often of the abdominal region - to enhance gastrointestinal motility, reduce muscle tension, and regulate autonomic function[104]. Recent interest has grown regarding its potential in IBS management; however, the literature is dominated by studies published in Chinese journals not indexed in MEDLINE, raising the possibility of language and publication bias. Non-English research excluded from mainstream databases has been shown to overestimate treatment effects[105]. Furthermore, tuina is characterized by substantial heterogeneity in technique, influenced by TCM diagnostic principles, regional schools, and practitioner experience, leading to wide variation in manipulation methods, frequency, intensity, and acupoint selection. This lack of standardization limits cross-study comparability and impedes mechanistic investigation, particularly regarding its effects on the brain-gut axis and autonomic regulation, which remain poorly understood.

In summary, although preliminary findings suggest potential benefits of tuina in IBS, the evidence base remains insufficient. Future research should prioritize rigorously designed, adequately powered randomized controlled trials with stringent bias control and standardized treatment parameters to improve reproducibility and support its integration into evidence-based IBS care.

Vibrating capsules

The vibrating capsule is a non-pharmacological, orally administered, and programmable device developed on the principle of physical therapy. It delivers mechanical vibrations within the intestine to stimulate the colonic wall, thereby enhancing motility rhythms and improving bowel function. This concept was first proposed by Ron et al[106]. The primary mechanism involves modulation of circadian rhythmic contractions of the colon, ultimately increasing the frequency of complete spontaneous bowel movements[107].

Currently, vibrating capsules such as VIBRANT (Vibrant Gastro, Inc., Newton, MA, United States) have received regulatory approval for the treatment of chronic idiopathic constipation[108]. Clinical studies have shown that, compared with placebo, these capsules significantly increase bowel movement frequency, relieve defecation difficulty, improve stool consistency, and enhance quality of life[109]. Although their efficacy in chronic idiopathic constipation has been preliminarily established, their application in IBS-C remains exploratory. To date, only a single early randomized controlled trial has evaluated their effects in IBS-C[106], and it found no significant improvement in overall colonic transit time compared with controls. This suggests that vibrating-capsule therapy may benefit only specific patient subgroups. Accordingly, future research should clarify the characteristics of potentially responsive populations and optimize stimulation parameters and dosing frequency to enable individualized treatment.

Biofeedback

Biofeedback is a behavioral therapy that uses instrument-assisted training to help patients perceive and voluntarily modulate physiological processes - such as muscle tension, skin temperature, heart rate variability, and visceral motility - that are typically beyond conscious control. Using real-time feedback from signals such as electromyography, anorectal pressure, or skin conductance, patients can identify and correct abnormal physiological patterns (e.g., excessive pelvic floor muscle tension or dysfunction), thereby improving related functional symptoms[110].

Early clinical studies (2011, 2014) investigating constipated patients with dyssynergic defecation comorbid with IBS reported that the presence of IBS did not significantly reduce treatment response, suggesting potential applicability in this population[111,112]. However, a 2019 meta-analysis concluded that high-quality evidence remains insufficient to confirm the efficacy of biofeedback for IBS, despite several small-scale trials reporting benefits[113]. This inconsistency reflects substantial limitations in available research, including small sample sizes, heterogeneous study designs, and nonstandardized outcome measures.

To strengthen scientific rigor and improve reliability, future studies should adopt more robust randomized controlled designs, use standardized outcome metrics (e.g., the IBS Symptom Severity Score, Composite Primary Symptom Relief), and collect safety data. Additionally, active control conditions matched in terms of practitioner-patient interaction intensity should be incorporated to minimize nonspecific effects and enhance the specificity and reproducibility of findings. These methodological improvements will support broader clinical translation and standardization of biofeedback therapy for IBS.

Spinal cord stimulation

Since its introduction for chronic pain management in 1967, spinal cord stimulation (SCS) has evolved into a neuromodulation technique with adjustable stimulation parameters[114]. Its therapeutic mechanism centers on modulating the electrical activity of dorsal column neurons to alter the transmission of visceral pain signals to the central nervous system[115]. SCS operates by placing electrodes in the epidural space, where the resulting electric field modifies neuronal transmembrane potentials and elicits action potentials in dorsal column axons. These propagate both anterogradely to supraspinal centers and retrogradely within the same or adjacent spinal segments, producing segmental and supraspinal modulation that collectively mediates analgesia[116].

Preliminary clinical studies demonstrate that SCS significantly reduces visceral pain and gastrointestinal discomfort in IBS patients, with particularly notable effects in those unresponsive to pharmacological treatments[117-119]. Animal models further corroborate these findings, consistently showing reductions in visceral hypersensitivity following SCS[120-122].

Despite its promise, SCS remains an invasive intervention with substantial challenges. Technical complications - including electrode malposition, suboptimal stimulation settings, and device-related issues such as infection or lead migration - can precipitate gastrointestinal adverse events[123,124]. Additionally, widespread adoption is constrained by high procedural costs and limited insurance reimbursement[125]. Therapeutic responses vary considerably across individuals, and evidence for sustained long-term benefit is still limited. The lack of standardized patient-selection criteria and validated predictors reduces clinical success rates while increasing risks and costs. Consequently, SCS is currently best reserved for treatment-refractory IBS. Future work should prioritize developing predictive models of treatment response, conducting comprehensive cost-effectiveness analyses, and improving access for underserved populations to support broader clinical implementation.

Sacral nerve stimulation

Sacral nerve stimulation (SNS) is a clinically established neuromodulation technique that improves defecation-related symptoms by electrically stimulating the sacral nerve pathways to regulate pelvic floor function[126]. Targeting sacral neural circuitry, SNS indirectly modulates anal sphincter activity and alters afferent signal transmission to the sacral cord and higher spinal centers, potentially influencing pain perception and autonomic regulation[127].

The first clinical application of SNS for IBS was reported in an early exploratory study. In that study, implanted electrodes coupled with an external stimulator delivered temporary neuromodulation to six patients with IBS-D, and short-term symptom improvement was observed[127]. Building on this foundation, the Fassov research group made substantial progress: A 2014 prospective study involving patients with IBS-D and IBS-M demonstrated clear therapeutic benefits of SNS across core IBS symptoms[128]. A subsequent 2019 clinical trial using optimized stimulation parameters further confirmed that SNS can significantly relieve abdominal pain in IBS. Basic research has also provided preliminary mechanistic insights[129]. Animal model studies indicate that SNS reduces visceral hypersensitivity in IBS models by suppressing hyperactivation of spinal dorsal horn neurons[130]. Additional evidence suggests that SNS may exert anti-inflammatory effects by modulating the intestinal immune microenvironment[130], although this remains to be verified clinically.

Despite its promise, SNS-based IBS therapy is still in an early clinical phase. Current evidence supports its potential value for IBS-D and IBS-M subtypes. As an invasive intervention, SNS entails substantial implementation costs; however, a 7-year economic evaluation suggests that it may ultimately be cost-effective compared with long-term standard follow-up.

DISCUSSION

Principal findings

This review provides a systematic overview of the physical therapy-based interventions currently applied in IBS, as summarized in Figure 1. The available literature indicates substantial heterogeneity among interventions with respect to evidence quality, methodological rigor, and consistency of outcomes, as detailed in Table 1. VNS shows biological plausibility, with mechanisms involving autonomic regulation and anti-inflammatory pathways; preliminary studies suggest symptom improvement, but evidence in adult IBS remains insufficient. Under controlled conditions, TENS may improve rectal hypersensitivity and related symptoms in IBS-D, although existing studies are small in scale. Brain-neuromodulation techniques such as TMS and tDCS have potential effects on visceral pain processing and emotional regulation networks; however, clinical data are limited and highly heterogeneous. Mechanistic evidence for EA is relatively robust, involving alterations in brain activity and inflammatory markers; however, clinical efficacy remains influenced by variability in stimulation parameters and acupoint selection. Studies on phototherapy, spa therapy, moxibustion, and tuina are largely exploratory or based on small sample sizes, and the overall level of evidence remains preliminary. The efficacy of vibrating capsules has been established in chronic constipation, but data specific to IBS-C remain limited. SCS and SNS as invasive neuromodulation techniques have shown potential benefits in early trials but are constrained by cost, procedural risks, and a lack of long-term data. Overall, physical therapies may offer potential benefits for selected patients with IBS, but the current evidence base remains fragmented and requires further systematic validation.

Figure 1 The illustration shows the major categories of physical therapies applied in irritable bowel syndrome and their representative clinical effects. EA: Electroacupuncture; HRV: Heart rate variability; MOX: Moxibustion; PBM: Photobiomodulation; SCS: Spinal cord stimulation; SNS: Sacral nerve stimulation; SPA: Spa therapy; tDCS: Transcranial direct current stimulation; TENS: Transcutaneous electrical nerve stimulation; TMS: Transcranial magnetic stimulation; VNS: Vagus nerve stimulation; QoL: Quality of life. Created in BioRender (Supplementary material).

Table 1 Clinical effects of physical therapies in irritable bowel syndrome.

Therapy	VAS pain	IBS-SSS	Rectal sensory threshold	fMRI activation	IBS-QOL	B-IBS	GSRS-IBS	IBS.S	Adverse events	Ref.
VNS	Baseline: 4-6; post-treatment: 1-3	Improved	-	-	Significantly improved	-	-	-	Mild adverse events only	[15,33,142,143]
TENS	Baseline: 3-9; post-treatment: 2-4	-	Significantly improved	-	-	-	-	-	NR	[39]
TMS	Baseline: 2-6; post-treatment: 1-5	-	Significantly improved	M1	-	-	-	-	Mild adverse events only	[50,157]
EA	Baseline: 2-8; post-treatment: 0-4	-	-	ACC, IC, PFC, INS, THA	-	-	-	-	NR	[75-77,158]
Spa therapy	-	-	-	-	-	-	-	-	Mild adverse events only	[96]
MOX	Baseline: 2-7; post-treatment: 0-4	Improved	-	ACC, IC, PFC	-	Significantly improved	-	-	Mild adverse events only	[16,98,101,102]
Vibrating capsule	-	-	-	-	-	-	-	-	Mild adverse events only	[145]
Biofeedback	-	Significantly improved	Improved	-	-	-	-	Significantly improved	NR	[111,112,159,160]
SCS	Baseline: 4-10; post-treatment: 1-6	Improved	-	-	-	-	-	-	Mild adverse events only	[117-119]
SNS	-	-	-	-	Significantly improved	-	Significantly improved	-	Serious adverse events reported	[127-129,146,161,162]

Adverse events were classified as “mild”, “serious”, or “not reported” according to the qualitative descriptions provided in the original studies. Quantitative incidence rates were not consistently reported and were therefore not available for summary in this table. ACC: Anterior cingulate cortex; B-IBS: Birmingham irritable bowel syndrome symptom questionnaire; CSBM: Complete spontaneous bowel movements; EA: Electroacupuncture; GSRS-IBS: Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome; IBS.S: Self-reported irritable bowel syndrome symptom score; IBS-SSS: Irritable Bowel Syndrome Symptom Severity Score; IC: Insular cortex; INS: Insula; M1: Primary motor cortex; MOX: Moxibustion; NR: Not reported; PFC: Prefrontal cortex; SCS: Spinal cord stimulation; SNS: Sacral nerve stimulation; TENS: Transcutaneous electrical nerve stimulation; THA: Thalamus; TMS: Transcranial magnetic stimulation; VAS: Visual analogue scale; VNS: Vagus nerve stimulation.

Brain-gut-immune-microbiota mechanisms underpinning physical therapies in IBS

IBS is a disorder of multidirectional dysregulation involving the central nervous system, enteric nervous system, immune signaling, and gut microbiota rather than a single-organ abnormality[21,57,131]. Neuroimaging studies demonstrate altered activity in visceral-emotional integration regions such as the ACC, insula, and prefrontal cortex, which correlates with visceral hypersensitivity and pain amplification in IBS[57,132]. Central dysregulation may exert top-down effects on gut function through vagal pathways[13,133,134]. At the peripheral level, IBS is characterized by low-grade, persistent immune activation, manifested by altered numbers or activation states of mast cells, T-cells, and macrophages in the intestinal mucosa; elevated pro-inflammatory cytokines including tumor necrosis factor-α, IL-6, and IL-1β; impaired epithelial barrier function; and increased intestinal permeability[12,135-137]. Aberrant immune signaling activates TRPV1 channels, leading to visceral pain and constituting a major mechanism underlying abdominal pain in IBS patients[138]. Dysregulated immune signaling can disrupt intestinal 5-hydroxytryptamine (5-HT) expression. In IBS-D, increased 5-HT levels are associated with diarrhea and urgency, while, in IBS-C, reduced 5-HT expression is associated with constipation and difficult defecation. The gut microbiota can modulate the intestinal immune environment through microbial metabolites, among which lipopolysaccharides induce low-grade immune activation and represent an important source of sustained immune stimulation in IBS[139]. Such as short-chain fatty acid-producing bacteria modulate epithelial barrier integrity and mucosal immunity and can transmit gut-derived signals to the central nervous system[140]. The vagus nerve and spinal nerves constitute critical communication pathways linking peripheral and central mechanisms in IBS[133,141]. The sacral nerve, as a key hub for pelvic sensory input and autonomic regulation, participates in defecation reflexes, rectal sensation, and immune modulation and influences global brain-gut axis function in IBS via bottom-up signaling. Although direct evidence remains limited, studies indicate that TMS can modulate prefrontal-limbic circuits involved in visceral perception, emotional processing, and brain-gut interactions, supporting its potential research value for elucidating central mechanisms underlying IBS[52,54,55]. Findings from clinical visceral pain populations indicate that tDCS may modulate central pain processing relevant to IBS[63]. VNS may modulate gut microbiota dysbiosis, and exert anti-inflammatory effects in IBS patients[15,33,142,143]. EA may alleviate visceral hypersensitivity by modulating TRPV1 channel activity[144]. The role of PBM in IBS remains to be elucidated despite anti-inflammatory effects observed in IBD[87]. Vibrating capsules, biofeedback, tuina, and SNS primarily target enteric mechanosensation and pelvic floor coordination and may be more suitable for IBS-C or mixed subtypes with prominent motility disturbances[111,129,145,146]. Physical therapies do not act through a single pathway but instead target distinct nodes along the brain-gut-immune-microbiota axis, generating systemic regulatory effects. This framework accounts for subtype-specific responses while underscoring current evidence limitations. Current evidence is largely limited to single-node, short-term studies without integrated cross-system validation.

Emerging biotechnological approaches

Against the backdrop of complex mechanistic challenges, rapid advances in biotechnology offer unprecedented opportunities for deciphering and translating physical therapy mechanisms. Single-cell multi-omics has revealed substantial heterogeneity among intestinal epithelial and neuronal cell populations[147], providing a molecular basis for IBS subtype classification and target identification. High-resolution neuroelectrophysiology tools enable fine-grained mapping of neuronal population dynamics within brain regions relevant to brain-gut signaling[148]. Gut organoids and organ-on-chip platforms create controllable in vitro models that span the gut-nerve-immune-microbe axis, facilitating mechanistic validation and therapeutic screening[149,150]. Clinically, advances in non-invasive monitoring - combining wearable biosensors with sensitive molecular imaging - are beginning to allow real-time assessment of brain-gut axis function, inflammatory states, and physiological rhythms, paving the way for personalized closed-loop intervention systems[151]. Precision microbiome tools, including engineered bacteriophages, enable targeted elimination of pathogenic bacteria[152,153]. Artificial intelligence-driven digital therapeutics integrate symptom tracking, psychological therapy, and stimulation control modules to enhance adherence and optimize treatment effects[154]. Additionally, smart materials paired with targeted drug delivery platforms provide new opportunities to synergize physical therapies with pharmacological interventions[155,156].

Strengths and limitations

This review synthesizes clinical evidence and mechanistic insights across diverse physical therapy modalities for IBS. Compared with prior reviews focusing on a single therapy or intervention category, this review summarizes mechanisms and clinical evidence for different physical interventions within an integrated brain-gut-immune-microbiota framework, aiming to inform clinicians and researchers. However, this review also has several limitations. Existing clinical studies vary in their levels of evidence, which partially limits direct comparison of effect sizes across different physical interventions. In addition, substantial heterogeneity in outcome measures and study designs further restricts comparability between therapies. Given the methodological heterogeneity and generally small sample sizes of the included studies, a formal risk-of-bias assessment or structured evidence grading was not undertaken in this narrative review. Future systematic evaluations incorporating standardized appraisal tools may further strengthen the clinical and guideline relevance of this field. Finally, although this review provides an integrative discussion of potential mechanisms underlying multiple physical therapies, evidence for some molecular pathways and signaling mechanisms is still largely derived from preclinical studies or indirect physiological markers and requires further validation in human mechanistic studies.

Future directions

Owing to the heterogeneity of IBS and the current limitations of pharmacotherapy, the role of physical therapies in multimodal management warrants further clarification. Combination strategies integrating physical and pharmacological therapies should be systematically evaluated in prospective trials. Given tolerability issues and limited recommendations for IBS-M, physical interventions may serve as adjuncts to improve symptom control and reduce drug burden, pending confirmation of synergistic effects in randomized trials. Mechanism-informed combinations of physical therapies represent a promising research direction. Advances such as single-cell multi-omics may enable biomarker-driven, pathophysiology-based personalization of physical therapies in IBS.

CONCLUSION

Physical therapies show exploratory potential as adjunctive, non-pharmacological approaches targeting the brain-gut axis in IBS. Available evidence from small trials suggests substantial variability in evidence strength among physical therapies. Mechanistic evidence primarily addresses neural and autonomic pathways, with other mechanisms inferred indirectly. Current evidence does not support physical therapies as first-line or broadly recommended treatments in guidelines. Treatment outcomes are strongly influenced by patient selection, symptom profiles, and individual responsiveness. Physical therapies should be considered adjuncts within individualized care alongside guideline-recommended pharmacotherapy, rather than as replacements for standard treatment strategies.

ACKNOWLEDGEMENTS

The authors would like to thank all colleagues and collaborators who contributed to discussions related to this work.