The autonomic nervous system plays a crucial role in regulating physiological processes including heart rate variability (HRV) and glucose metabolism. Higher glucose levels have been associated with reduced vagally mediated HRV. Resonance frequency breathing (RFB) with HRV biofeedback (HRV-BF) has been shown to enhance vagally mediated cardiac autonomic modulation in healthy adults. However, it remains unclear whether such training alters cardiac autonomic responses during acute metabolic stress. We investigated whether four weeks of the RFB-HRV-BF intervention modifies autonomic response dynamics during a metabolic challenge in 28 healthy adults (n = 16 females, mean age: 25.68 ± 3.66 years; mean body mass index 22.77 ± 3.01 kg/m2). Cardiac autonomic responses were assessed using the HRV parameters root mean square successive differences between normal heartbeats (RMSSD) and standard deviation of all normal-to-normal intervals (SDNN) during the first 30 min of a 75 g oral glucose tolerance test (OGTT), corresponding to peak postprandial glucose levels, before and after the intervention. Piecewise linear mixed-effects models revealed a less pronounced decline in logarithmic naturals transformed RMSSD (lnRMSSD) and SDNN (lnSDNN), during the early postprandial phase of the OGTT following the RFB-HRV-BF intervention, indicating an intervention-related modification of cardiac autonomic response dynamics. Taken together, these findings indicate that RFB-HRV-BF attenuates early vagal withdrawal during acute metabolic stress. By demonstrating effects on cardiac autonomic dynamics during a standardised metabolic challenge, the present study extends previous work on RFB beyond resting conditions and underscores the relevance of context-dependent autonomic assessment for understanding interactions between autonomic regulation and metabolic health.
The increasing complexity of vocal training, particularly in the control of internal physiological processes, necessitates the integration of technologies capable of enhancing sensorimotor learning and self-regulation. Traditional vocal pedagogy remains limited in accessing and monitoring underlying physiological mechanisms, resulting in a gap between subjective perception and objective performance control. The present study aimed to evaluate whether an immersive training environment integrating virtual reality and multimodal biofeedback could improve short-term physiological, acoustic, and cognitive outcomes during vocal training compared with conventional instruction. A randomized controlled pre–post design was implemented across three universities in China (Beijing). The sample comprised 107 students (aged 18–30 years), randomly assigned to a control group (n = 53) and an experimental VR group (n = 54). The findings indicate significant improvements in the VR group: a reduction in muscle activity (− 6.29 vs. −2.93 in the control group; p < 0.001; d = 0.71) and respiratory variability (− 0.048 vs. −0.022; p < 0.001; d = 1.05). Additionally, increased pitch stability (4.91 vs. 2.37; p < 0.001; d = 0.78) and reduced shimmer were observed. A negative correlation was identified between vocal awareness and EMG (r = − 0.273; p = 0.004). Participants receiving VR-based multimodal biofeedback demonstrated greater short-term improvements in physiological, acoustic, and subjective outcomes than those receiving conventional instruction. These findings are consistent with enhanced sensorimotor adaptation during training within an information-rich learning environment. Although further studies are required to evaluate long-term retention, transfer of learning, and the independent contributions of VR and biofeedback, the proposed approach may complement existing vocal pedagogy by providing learners with additional physiological information during practice.
Chronic pain patients often exhibit altered processing of internal bodily sensations, especially in the musculoskeletal domain, and impaired body awareness. This case-control study investigated the association between resting electromyographic (EMG) activity, musculoskeletal tension discrimination and body awareness in chronic headache (CH) patients compared to healthy controls (HC). Twenty-one patients diagnosed with chronic headache and 22 matched healthy controls performed a muscle tension discrimination task while EMG was recorded from the frontalis (pain-related) and biceps brachii (pain-unrelated) muscles. Questionnaires assessed body awareness and pain-related cognitive and affective factors. Compared to HC, CH patients showed higher resting muscle activity (β = 1.32; p < 0.001) and lower discrimination (β = -0.12; p = 0.007) only in the pain site. CH patients exhibited reduced body awareness (η²p = 0.19; p = 0.003), higher anxiety (β = 3.10; p = 0.032), catastrophizing (η²p = 0.30; p < 0.001), and helplessness (η²p = 0.19; p = 0.004). Notably, lower muscle tension discrimination was associated with both higher resting frontalis EMG (ρs = -0.31; p = 0.043) and catastrophizing (ρs = -0.39; p = 0.009). Patients with CH exhibit a site-specific deficit in muscle tension discrimination, accompanied by elevated resting pericranial muscle tension, reduced body awareness, and maladaptive cognitive coping strategies. The association between catastrophizing and impaired discrimination highlights the interplay between cognitive-affective factors and psychophysiological dysregulation in CH. These findings underscore the importance of multidimensional assessment in patients with CH in order to identify targeted psychophysiological treatment.
To evaluate the effectiveness of biofeedback interventions for pain management and rehabilitation outcomes in athletes and individuals with sports-related injuries. Systematic review of randomized controlled trials. A systematic literature search was conducted in eight electronic databases: PubMed, Google Scholar, Web of Science, Scopus, ProQuest, PEDro, SPORTDiscus, and the Cochrane Central Register of Controlled Trials. Searches were completed in September 2024 and updated in November 2025. Randomized controlled trials investigating the use of biofeedback interventions for pain management and rehabilitation in athletes or individuals with sports-related injuries were eligible for inclusion. Due to heterogeneity in participant characteristics, injury types, biofeedback modalities, and outcome measures, a narrative synthesis was performed. Methodological quality was assessed using the Cochrane Risk of Bias tool. Nine randomized controlled trials from Saudi Arabia, Taiwan, Canada, Romania, Brazil, and Iran were included. Biofeedback interventions addressed patellofemoral pain, shoulder impingement, chronic ankle instability, plantar fasciitis, post-traumatic osteoarthritis, chronic low back pain, meniscal injuries, and other musculoskeletal sports injuries. Modalities included electromyography, heart rate variability, neurofeedback, virtual reality feedback, and real-time visual gait retraining. Biofeedback was associated with reduced pain, improved muscle activation and strength, enhanced functional recovery, and better rehabilitation outcomes. Biofeedback may be a valuable adjunct to conventional rehabilitation for athletes or individuals with sports-related injuries. For clinicians, it can enhance neuromuscular control, patient engagement, and functional outcomes in multimodal programs. However, the certainty of the evidence is low, and further high-quality trials across diverse populations are needed.
Auricular neuromodulation specificity remains debated, particularly for electrical approaches in which current spread may obscure site-specific effects. We tested whether focal mechanical auricular acupressure produces site-by-pathway differences across Hot affective interference control and Cold inhibitory braking. In a single-blind, randomized, active-controlled study, 55 young adults with elevated affective symptoms received 48-h auricular acupressure at Shenmen, Subcortex, Combined (Shenmen + Subcortex), or an active Shoulder control site. Participants completed an Emotional Flanker task indexing Hot control and an Emotional Go/No-Go task indexing Cold control. Standardized change scores were analyzed using linear mixed-effects models, with hierarchical drift diffusion modeling and signal detection theory analyses used to constrain mechanistic interpretation. A significant Group × Pathway interaction was observed (p = 0.002). In the Cold pathway, Subcortex and Combined stimulation showed greater improvement than Shenmen stimulation. In the Hot pathway, Shenmen stimulation showed greater improvement than Subcortex stimulation, whereas Hot-pathway contrasts against the active control were non-significant. Focal auricular acupressure produced pathway-selective, site-dependent profiles across Hot and Cold executive-control tasks. These findings suggest relative site-by-pathway specificity, although further studies with larger samples and optimized control conditions are needed to confirm the robustness and mechanisms of this effect.
